Patent Publication Number: US-2023132413-A1

Title: Oral Care System and Method

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     The present application is a continuation-in-part of: (1) U.S. Pat. Application Serial No. 17/536,273, filed Nov. 29, 2021, which is a divisional of U.S. Pat. Application Serial No. 15/350,266, filed Nov. 14, 2016, now U.S. Pat. No. 11,213,120; (2) U.S. Pat. Application Serial No. 16/949,630, filed Nov. 9, 2020, which is a divisional of U.S. Pat. Application Serial No. 15/350,223, filed Nov. 14, 2016, now U.S. Pat. No 10,835,028; (3) U.S. Pat. Application Serial No. 17/302,326, filed Apr. 30, 2021, which is a continuation of U.S. Pat. Application Serial No. 15/350,285, filed Nov. 14, 2016, now U.S. Pat. No. 11,043,141; and (4) U.S. Pat. Application Serial No. 15/350,298, filed Nov. 14, 2016. The aforementioned priority applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     In attempting to improve oral care routines, it is typical to focus on the oral care routine employed by an individual and how that oral care routine differs from an accepted standard. The individual is then guided on how to change their oral care routine to better conform with the accepted standard. By conforming to the standard, it is expected that the overall effectiveness of the individual’s oral care routine will improve, thereby improving the oral health of the individual. Having everyone conform to an accepted standard is an ideal, and perhaps not one that everyone is capable of achieving. For those who cannot or do not conform to the accepted standard for an oral care routine, for whatever the reason, it is desirable to provide a system and method that can still aid them in maintaining an effective oral care routine. 
     Furthermore, an oral care system can utilize one or more sensors to evaluate the effectiveness of a brushing session. These approaches, however, do not consider that a user may have different goals for different brushing sessions or that different users may have different oral characteristics. For example, while an evening brushing session may be intended for a deep cleaning, an afternoon brushing session may be intended as a quick cleaning to remove noticeable food particles and freshen the breath. In addition, a user may have oral sensitivity in a certain area of the mouth that affects the user’s ability to brush teeth in this area. Thus, there is need for a method of determining a brushing routine and/or evaluating a brushing session that considers the user’s brushing goals and unique oral characteristics. 
     BRIEF SUMMARY 
     One aspect of the present disclosure may be directed to an oral care systems and methods which adapt a user’s brushing routine and/or brushing evaluation to account for one or more physical properties of a selected toothbrush. The oral care system may include an oral care device and a data processing unit. In one embodiment, the data processing unit collects data concerning one or more physical properties of the toothbrush being used, and based on the collected data, the data processing unit determines a suggested brushing routine for the user and/or an evaluation of a brushing session of a user. 
     In one embodiment, the oral care system includes: a toothbrush having a physical property; and a programmable processor configured to: receive physical property data indicative of the physical property of the toothbrush; and determine a suggested brushing routine based at least in part upon the received physical property data. 
     In another embodiment, the invention can be an oral care system including: a toothbrush comprising a physical property; and a programmable processor configured to: receive physical property data indicative of the physical property of the toothbrush; and determine an evaluation of a brushing session based at least in part upon the physical property data. 
     In yet another embodiment, the invention may be a method for oral care including: receiving, by a programmable processor, physical property data indicative of a physical property of a toothbrush; and determining, by the programmable processor, a suggested brushing routine based at least in part upon the received physical property data. 
     In still another embodiment, the invention may be a method for oral care including: receiving, by a programmable processor, physical property data indicative of a physical property of a toothbrush; and determining, by the programmable processor, an evaluation of a brushing session based at least in part upon the physical property data. 
     Another aspect of the present disclosure may be directed to an oral care systems and methods which adapt to a user’s brushing routine, taking into account the user’s brushing habits, in order to improve the overall efficacy of the user’s brushing routine. The oral care system includes an oral care device and a programmable processor. In one embodiment, the oral care device generates data concerning a user’s brushing habits and the programmable processor analyzes the generated data. The programmable processor determines a target brushing time based upon the generated data and may communicate the target brushing time to the user during the brushing routine. The target brushing time may be determined section-by-section for the user’s dentiture, thereby accounting for the user’s different brushing habits for different sections of their dentiture. In addition, the target brushing time may be adjusted in real time to account for changes in the user’s brushing habits. The oral care method includes steps of generating data concerning a user’s brushing habits and determining appropriate target brushing time based upon the generated data. The target brushing time may also be communicated to the user during the brushing routine. 
     In another embodiment, the invention can be an oral care system including: an oral care device including: at least one teeth cleaning element; and at least one sensor configured to detect motion of the oral care device during a brushing routine of a user and to generate sensor data corresponding to the detected motion; and a programmable processor configured to: receive the sensor data generated by the at least one sensor; and determine a target brushing time based on the sensor data. 
     In yet another embodiment, the invention may be an oral care system including: an oral care device including: at least one teeth cleaning element; at least one sensor configured to detect a brushing intensity during a brushing routine of a user and to generate sensor data corresponding to the detected brushing intensity; and a programmable processor configured to: receive the sensor data generated by the at least one sensor; and determine a target brushing time based on the sensor data. 
     In another embodiment, the invention may be a method for oral care including: a) receiving sensor data from at least one sensor configured to detect motion of an oral care device during a brushing routine of a user, the sensor data corresponding to the detected motion; and b) determining a target brushing time based on the sensor data. 
     In still another embodiment, the invention may be a method for oral care including: a) receiving sensor data from at least one sensor configured to detect brushing intensity during a brushing routine of a user, the sensor data corresponding to the detected brushing intensity; and b) determining a target brushing time based on the sensor data. 
     Another aspect of the present disclosure may be directed to an oral care system including a toothbrush; a user interface configured to receive a brushing goal from a user; and a programmable processor operably coupled to the user interface, the programmable processor configured to receive brushing goal data indicative of the brushing goal received by the user interface; and determine, based at least in part on the brushing goal data, at least one of a suggested brushing routine and a brushing evaluation for a brushing session. 
     In another embodiment, an oral care method includes receiving, at a user interface, a brushing goal from a user; generating brushing goal data indicative of the brushing goal received by the user interface; and determining, at a programmable processor, at least one of a suggested brushing routine that is based at least in part on the brushing goal data; and a brushing evaluation for a brushing session that is based at least in part on the brushing goal data. 
     In yet another embodiment, an oral care system includes a toothbrush; and a data processing unit comprising a user interface configured to receive a brushing goal from a user; and a programmable processor operably coupled to the user interface, the programmable processor configured to receive brushing goal data indicative of the brushing goal received by the user interface; determine a suggested brushing routine based at least in part on the brushing goal data; and determine a brushing evaluation for a brushing session based at least in part on the brushing goal data and brushing data from the brushing session. 
     Another aspect of the present disclosure may be directed to an oral care system including a toothbrush; a programmable processor configured to receive oral characteristic data indicative of an oral characteristic of a user; and determine for the user, based at least in part on the oral characteristic data, at least one of a suggested brushing routine and a brushing evaluation for a brushing session. 
     In another embodiment, an oral care method includes receiving, by a programmable processor, oral characteristic data indicative of an oral characteristic of a user; and determining for the user, by the programmable processor, based at least in part on the oral characteristic data, at least one of a suggested brushing routine and a brushing evaluation for a brushing session. 
     In yet another embodiment, an oral care system includes a toothbrush; and a data processing unit comprising a user interface configured to receive an oral characteristic from a user; and a programmable processor configured to receive oral characteristic data indicative of the oral characteristic received by the user interface; determine for the user, based at least in part on the oral characteristic data, a suggested brushing routine; and determine for the user, based at least in part on the oral characteristic data, a brushing evaluation for a brushing session. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the exemplary embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown in the following figures: 
         FIG.  1 A  illustrates an oral care system in accordance with an embodiment of the present invention, the oral care system being in communication with a server. 
         FIG.  1 B  schematically illustrates electronic components of the data processing unit shown in  FIG.  1 A ; 
         FIG.  2    is a flowchart showing a process for determining a brushing routine and a brushing evaluation from one or more physical properties of a toothbrush in accordance with an embodiment of the invention; 
         FIG.  3 A  is a flowchart showing a process for determining a brushing routine from one or more physical properties of a toothbrush in accordance with an embodiment of the invention; 
         FIG.  3 B  is illustrates a data processing unit having a user interface whereby a user may input physical property data; 
         FIG.  3 C  is illustrates a data processing unit having a user interface providing brushing instructions for a brushing routine; 
         FIG.  3 D  is a data processing unit having a user interface providing an evaluation of a brushing session of a user; 
         FIG.  4    illustrates a toothbrush in a packaging for use as part of an oral care system in accordance with another embodiment of the present invention; 
         FIG.  5    illustrates a toothbrush having a radio frequency identification (RFID) tag; 
         FIG.  6    illustrates a toothbrush having an appearance which may be identified by the data processing unit of  FIG.  1 B ; 
         FIG.  7    illustrates a toothbrush having a chamber containing an oral care additive; 
         FIG.  8    illustrates an electronic toothbrush having a detachable head; 
         FIG.  9    illustrates a detachable head for an electronic toothbrush including an RFID tag; 
         FIG.  10    illustrates an interface between the head and the handle of an electronic toothbrush; 
         FIG.  11    illustrates a partial sectional view of a toothbrush having electronic circuitry for collecting brushing session data; 
         FIG.  12    schematically illustrates electronic components of the toothbrush of  FIG.  11   ; 
         FIG.  13    illustrates a toothbrush and a dongle, the dongle having electronic circuitry for collecting brushing session data; 
         FIG.  14 A  illustrates an oral care system in accordance with another embodiment of the present invention, the oral care system being in communication with a server; 
         FIG.  14 B  illustrates a partial sectional view of a toothbrush of the oral care system of  FIG.  14 A ; 
         FIG.  14 C  schematically illustrates electronic components of the toothbrush of  FIG.  14 B ; 
         FIG.  14 D  schematically illustrates electronic components of a data processing unit shown in  FIG.  14 A ; 
         FIG.  15    illustrates a toothbrush and a dongle useable with an oral care system in accordance with another embodiment of the present invention; 
         FIGS.  16 A-D  graphically illustrate four different types of motion for an oral care device; 
         FIG.  17    is a graph illustrating a comparison between y-axis acceleration and z-axis acceleration versus time for an oral care device; 
         FIG.  18    is a graph illustrating z-axis acceleration versus y-axis acceleration for an oral care device; 
         FIG.  19    is a graph illustrating rotational accelerations about three axes for an oral care device; 
         FIG.  20    is a chart showing a brushing profile with the proportion of each of the four brush stroke motions of  FIGS.  16 A-D  over time; 
         FIG.  21    is a flowchart showing a process for determining the target brushing time of a brushing routine, based on brush style motion, to achieve more efficient oral care using the oral care system of  FIG.  14 A ; 
         FIG.  22    illustrates different portions of the dentiture of a user for which the brushing routine may be independently analyzed and brushing times varied by the oral care system of  FIG.  14 A ; 
         FIG.  23 A  is a first chart showing a comparison between two different stroke rates for an oral care device; 
         FIG.  23 B  is a second chart showing a comparison of power spectral density between two different stroke rates for an oral care device; 
         FIG.  24    is a flowchart showing a process for determining the target brushing time of a brushing routine, based on brushing aggressiveness, to achieve better oral care using the oral care system of  FIG.  14 A ; 
         FIG.  25 A  illustrates an oral care system according to another embodiment of the present invention; 
         FIG.  25 B  is a schematic of the electronic circuitry of the data processing unit of  FIG.  25 A ; 
         FIG.  26    is a flowchart showing a process for determining a brushing routine and a brushing evaluation from a brushing goal according to an embodiment of the invention; 
         FIG.  27    illustrates a data processing unit having a user interface whereby a user inputs a brushing goal according to an embodiment of the invention; 
         FIG.  28    illustrates a toothbrush comprising a user interface according to an embodiment of the invention; 
         FIG.  29    illustrates a data processing unit having a user interface that provides brushing instructions for a brushing routine according to an embodiment of the invention; 
         FIG.  30   illustrates a data processing unit having a user interface that provides an evaluation of a brushing session of a user according to an embodiment of the invention; 
         FIG.  31    illustrates an electronic toothbrush according to an embodiment of the invention; 
         FIG.  32    illustrates a partial sectional view of a toothbrush having electronic circuitry for collecting brushing session data according to an embodiment of the invention; 
         FIG.  33    is a schematic of the electronic circuity of the toothbrush of  FIG.  32   ; 
         FIG.  34    illustrates a toothbrush dongle having electronic circuitry for collecting brushing session data. 
         FIG.  35 A  illustrates an oral care system according to another embodiment of the present invention; 
         FIG.  35 B  is a schematic of the electronic circuitry of the data processing unit of  FIG.  35 A ; 
         FIG.  36    is a flowchart showing a process for determining a brushing routine and a brushing evaluation based on oral characteristic data according to an embodiment of the invention; 
         FIG.  37 A  illustrates a data processing unit having a user interface providing a question and answer options regarding an oral characteristic according to an embodiment of the invention; 
         FIG.  37 B  illustrates a data processing unit having a user interface providing a statement and response options regarding an oral characteristic according to an embodiment of the invention; 
         FIG.  38    illustrates a toothbrush comprising a user interface according to an embodiment of the invention; 
         FIG.  39    illustrates a data processing unit having a user interface that provides brushing instructions for a brushing routine according to an embodiment of the invention; 
         FIG.  40    illustrates a data processing unit having a user interface that provides an evaluation of a brushing session of a user according to an embodiment of the invention; 
         FIG.  41    illustrates an electronic toothbrush according to an embodiment of the invention; 
         FIG.  42    illustrates a partial sectional view of a toothbrush having electronic circuitry for collecting brushing session data according to an embodiment of the invention; 
         FIG.  43    is a schematic of the electronic circuity of the toothbrush of  FIG.  42   ; and 
         FIG.  44    illustrates a toothbrush dongle having electronic circuitry for collecting brushing session data according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “left,” “right,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Further, as used herein, the phrase “based on” is to be interpreted as meaning “based at least in part on,” and therefore is not limited to an interpretation of “based entirely on.” Moreover, the features and benefits of the invention are illustrated by reference to the preferred embodiments. Accordingly, the invention expressly should not be limited to such preferred embodiments illustrating some possible non-limiting combinations of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto. 
     Features of the present invention may be implemented in software, hardware, firmware, or combinations thereof. The programmable processes described herein are not limited to any particular embodiment, and may be implemented in an operating system, application program, foreground or background processes, driver, or any combination thereof. The computer programmable processes may be executed on a single processor or on or across multiple processors. 
     Processors described herein may be any central processing unit (CPU), microprocessor, micro-controller, computational, or programmable device or circuit configured for executing computer program instructions (e.g. code). As used herein, the terms “processor” and “programmable processor” are used interchangeably. Various processors may be embodied in computer and/or server hardware of any suitable type (e.g. desktop, laptop, notebook, tablets, cellular phones, etc.) and may include all the usual ancillary components necessary to form a functional data processing device including without limitation a bus, software and data storage such as volatile and non-volatile memory, input/output devices, graphical user interfaces (GUIs), removable data storage, and wired and/or wireless communication interface devices including Wi- Fi, Bluetooth, LAN, etc. 
     Computer-executable instructions or programs (e.g. software or code) and data described herein may be programmed into and tangibly embodied in a non-transitory computer-readable medium that is accessible to and retrievable by a respective processor as described herein which configures and directs the processor to perform the desired functions and processes by executing the instructions encoded in the medium. A device embodying a programmable processor configured to such non-transitory computer-executable instructions or programs is referred to hereinafter as a “programmable device”, or just a “device” for short, and multiple programmable devices in mutual communication is referred to as a “programmable system”. It should be noted that non-transitory “computer-readable medium” as described herein may include, without limitation, any suitable volatile or non-volatile memory including random access memory (RAM) and various types thereof, read-only memory (ROM) and various types thereof, USB flash memory, and magnetic or optical data storage devices (e.g. internal/external hard disks, floppy discs, magnetic tape CD-ROM, DVD-ROM, optical disk, ZIP™ drive, Blu-ray disk, and others), which may be written to and/or read by a processor operably connected to the medium. 
     In certain embodiments, the present invention may be embodied in the form of computer-implemented processes and apparatuses such as processor-based data processing and communication systems or computer systems for practicing those processes. The present invention may also be embodied in the form of software or computer program code embodied in a non-transitory computer-readable storage medium, which when loaded into and executed by the data processing and communications systems or computer systems, the computer program code segments configure the processor to create specific logic circuits configured for implementing the processes. 
     Turning in detail to the drawings,  FIG.  1 A  illustrates an oral care system  101  in accordance with an embodiment of the present invention. The oral care system  101  includes a toothbrush  103  and a data processing unit  105 . The data processing unit  105  may communicate with a server  107  for purposes of storing larger amounts of data or to provide server-side processing functionality. The presence of the server  107  and communication between the data processing unit  105  and the server  107 , however, are not limiting of the present invention, unless specifically set forth in a claim. 
     The toothbrush  103  may be of any type which includes teeth cleaning elements suitable for cleaning teeth. The toothbrush  103  includes at least one physical property, which may be any feature of the toothbrush related to cleaning teeth or to oral care in general. The at least one physical property may be the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the angle of the head with respect to the handle, the flexibility of the material from which all or a part of the toothbrush is constructed, the head size of the toothbrush, the size of the handle, the presence of an oral care additive, whether the toothbrush is manual or electric, the presence of an electrically-powered vibratory element, the presence of an elastomeric element in the bristle field, the presence of a tongue cleaner, the mobility of a first portion of the toothbrush with respect to a second portion of the toothbrush, and the like, amongst many other types of physical properties. Certain physical properties of toothbrushes are discussed further below, and the invention is not limited to any particular physical property of a toothbrush unless specifically set forth in a claim. It is also to be understood, therefore, that the invention is not limited to the toothbrush  103  illustrated as part of the exemplary embodiment. 
     The toothbrush  103  shown in  FIG.  1 A  generally includes a handle  111 , a neck  113 , and a head  115 . The neck  113  extends between the handle  111  and the head  115  and connects the head  115  to the handle  111 . The handle  111  provides the user with a mechanism by which the toothbrush  103  can be readily gripped and manipulated during a brushing session. The handle  111  may be formed of many different shapes, sizes and materials and may be formed by a variety of manufacturing methods that are well-known to those skilled in the art. The handle  111  extends from a proximal end  117  to a distal end  119  to form an elongated gripping portion  123  therebetween. The handle  111  transitions into the neck  113  at the distal end  119 . While the neck  113  generally has a smaller transverse cross-sectional area than the handle  111 , the invention is not so limited. Broadly speaking, the neck  113  forms a transition region between the handle  111  and the head  115 , with the head  115  extending from a proximal end  125  at the end of the neck  113  opposite the handle  111  to a distal end  127 . While the head  115  is normally widened relative to the neck  113 , in some embodiments the head  115  can simply be a continuous extension or narrowing of the neck  113  and/or handle  111 . 
     The handle  111 , the neck  113 , and the head  115  may be formed as separate components which are operably connected at a later stage of the manufacturing process by any suitable technique known in the art, including without limitation thermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve, threaded engagement, adhesion, or fasteners. However, in other embodiments, the handle  111 , the neck  113 , and the head  115  of the toothbrush  103  may be formed as a single unitary structure using a molding, milling, machining, or other suitable process. In certain embodiments, the neck  113  may be made from a material which is more flexible than the handle  111  or the head  115 , and in such embodiments, the flexibility of the neck  113  provides the head  115  with mobility with respect to the handle  111 . Whether the handle  111 , the neck  113 , and the head  115  are of a unitary or multi-piece construction (including connection techniques) is not limiting of the present invention, unless specifically set forth in a claim. In some embodiments of the invention, the head  115  can have a first portion that is flexibly attached to a second portion of the head  115 . During brushing, the first portion can move with respect to the second portion to enhance the brush head’s ability to reach certain portions of the dentiture. In some embodiments of the invention, the head  115  may be detachable (and replaceable) from the handle  111  and/or from the neck  113  using techniques known in the art. 
     The head  115  generally includes a front surface  143 , a rear surface  145  and peripheral side surfaces  147  that extend between the front and rear surfaces  143 ,  145 . The front surface  143  and the rear surface  145  of the head  115  can take on a wide variety of shapes and contours, none of which are limiting of the present invention. For example, the front and rear surfaces  143 ,  145  can be planar, contoured or combinations thereof. 
     The front surface  143  of the head  115  includes at least one teeth cleaning element, shown in the exemplary embodiment as a plurality of bristles  149 , extending therefrom for cleaning teeth surfaces. As used herein, the term “teeth cleaning element” is used in a generic sense to refer to any structure that can be used to clean or polish the teeth through relative surface contact. In certain embodiments, the head  115  may include a single teeth cleaning element, and in other embodiments, the head  115  may include two or more teeth cleaning elements. Common examples of the at least one teeth cleaning element include, without limitation, bristle tufts, filament bristles, fiber bristles, nylon bristles, spiral bristles, rubber bristles, elastomeric protrusions, flexible polymer protrusions, combinations thereof and/or structures containing such materials or combinations. Suitable elastomeric materials include any biocompatible resilient material suitable for uses in an oral hygiene apparatus. To provide optimum comfort as well as cleaning benefits, the at least one teeth cleaning element may be an elastomeric material having a hardness property in the range of A8 to A25 Shore hardness. Other materials within and outside the noted hardness range may also be used. 
     The bristles  149  of the toothbrush  111  can be connected to the head  115  in any manner known in the art. For example, staples/anchors, in-mold tufting (IMT) or anchor free tufting (AFT) could be used to mount the bristles  149  of the exemplary embodiment. In AFT, a plate or membrane is secured to the brush head such as by ultrasonic welding. The bristles extend through the plate or membrane. The free ends of the bristles on one side of the plate or membrane perform the cleaning function. The ends of the bristles on the other side of the plate or membrane are melted together by heat to be anchored in place. Alternatively, the bristles may be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles are mounted within or below the tuft blocks. 
     Referring to both  FIGS.  1 A and  1 B , the data processing unit  105  includes a housing  163  and electronic circuitry  165 , with the housing  163  enclosing and/or supporting the various components of the electronic circuitry  165 . The electronic circuitry  165  includes a power source, shown as a battery  167  in the exemplary embodiment. Of course, the invention is not so limited, and other types of power sources may be used. The electronic circuitry  165  also includes a processor  169  communicably coupled to a memory  171 , a communication module  173 , a display  175 , an optical imaging subsystem which is shown as a camera  177 , and a radio frequency identifier (RFID) tag reader  179 . 
     In certain embodiments, one or both of the optical imaging subsystem  177  and the RFID tag reader  179  may be excluded as optional parts of the electronic circuitry  165 . In certain embodiments, the electronic circuitry  165  may include other components, such as a speaker to provide audible feedback to the user, one or more buttons to receive input from the user, and one or more ports for making a wired connection between the electronic circuitry  165  and other circuitry external to the data processing unit  105 . In certain other embodiments, the data processing unit  105  may be a smartphone, a tablet computer, a laptop computer, and the like, although the invention is not so limiting. In the exemplified embodiment, the electronic circuitry  165  is located within housing  163  of the data processing unit  105 , this housing  163  being separate and distinct from the housing  103 A of the toothbrush  103  In other embodiments, the electronic circuitry  165  or certain components thereof may be located within the housing  103 A of the toothbrush  103 . 
     The memory  171  may be any appropriate type of memory or storage which enables the processor  169  to perform the desired programming, such as volatile and/or non-volatile random access memory. The particular type of storage used for the memory  171  is not to be limiting of the invention. 
     The display  175  may be any type of light emitting display, and as shown in the exemplary embodiment, the display  175  may be an LED panel. In certain other embodiments, the display  175  may be an LCD panel, an OLED panel, or any other type of display which is electronically controllable by the programmable processor  169  to provide visual feedback to the user. In certain embodiments, the display  175  may be a touch sensitive display which accepts input from the user directly on the display surface. Such a touch sensitive display may therefore serve as a user interface for the data processing unit  105 . The type and configuration of the display  175  is not limiting of the invention unless specifically set forth in a claim. Similarly, the type and configuration of the user interface is not limiting of the invention unless specifically set forth in a claim. 
     The communication module  173  may include an antenna  181  to enable wireless transmission of communication signals. The communication module  173  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, Bluetooth@, and the like, or it may communicate using any type of proprietary wireless transmission protocol. The mode of communication for which the communication module  173  is configured is not limiting of the invention unless specifically set forth in a claim. In certain embodiments, the communication module  173  may include a port to enable communications using wires and wired protocols, such as USB and the like. 
     The communication module  173  of the data processing unit  105  may be configured and/or programmed to communicate with the server  107 . The communication module  173  may communicate with the server  107  over any combination of public and/or private network, and the communications may be wired, wireless, or a combination of the two. In certain embodiments, the communication module  173  may communicate with the server  107  over the Internet using one or more types of communication protocols. In certain embodiments, the server  107  may be programmed with one or more application programming interfaces (APIs) which provides server-side functionality to the data processing unit  105 . 
     A flowchart  201  showing an exemplary process for determining a suggested brushing routine is shown in  FIG.  2   . The process of this flowchart  201  may be implemented as programming for the programmable processor  169  of the data processing unit  105 . For convenience, as part of the description below, reference will also be made to the hardware components of the data processing unit  105  discussed above in  FIG.  1 B . While in the exemplified embodiment the processor  169  and other electronic circuitry  165  form part of the data processing unit, the disclosure is not so limited. For example, in other embodiments, a processor forming part of the toothbrush can carry out the steps carried out by processor  169  in the embodiments discussed herein. 
     The process starts out with a receiving step  203  in which the processor  169  receives physical property data associated with the toothbrush. The physical property data that is received is representative of one or more physical properties of the toothbrush. For purposes of the present disclosure, the term “physical property data” is any type of information indicative of a physical property of a toothbrush, including information extracted or derived from other information or data indicative of a physical property of a toothbrush, regardless of the form of the extracted information. The physical property data may be in the form of mathematical data, analog data, and/or digital data. 
     As is discussed below, receiving step  203  may be achieved in any number of ways. In certain embodiments, the user may input the physical property data through a user interface of the data processing unit  105 . In such embodiments, the data processing unit  105  may use the display  175  to present to the user one or more questions concerning at least one physical property of the toothbrush and then receive the physical property data as answers to the one or more questions. In certain embodiments, the physical property data may be received by the data processing unit by imaging the toothbrush or indicia associated with the toothbrush using the camera  177 . In certain embodiments, the physical property data may be received using the RFID tag reader  179 . In certain embodiments, the physical property data may be received from the server  107  in response to a toothbrush identifier being transmitted to the server  107  by the data processing unit  105 . The toothbrush identifier may be input using any one or more of the user interface, the camera  177 , the RFID tag reader  179 , and/or any other subsystem that may be included as part of the data processing unit  105 . In still other embodiments, one or more of the aforementioned processes for receiving the physical property data may be used in combination. 
     Following the receiving step  203  is a determining step  205 , and in this determining step  205  a suggested brushing routine is determined based upon the received physical property data. This determining step  205  may also be achieved in any number of ways. In certain embodiments, the suggested brushing routine may be determined by presenting the user with a list of potential brushing routines and having the user select the suggested brushing routine from among the list of potential brushing routines. In certain embodiments, the suggested brushing routine may be determined by making adjustments to a standardized brushing time based on the physical property data, as described below. In certain embodiments, the suggested brushing routine may be determined by selecting a predetermined brushing routine based on the physical property data and then adjusting the predetermined brushing routine based on a user brushing history. In such embodiments, the user brushing history may be based upon brushing session data collected from previous brushing sessions of the user. Such brushing session data may be based upon brush stroke, brushing aggressiveness, or upon any other measure of brushing effectiveness. In addition, such brushing session data may be saved in the memory  171  of the data processing unit  105  or in a memory of the server  107 . In still other embodiments, one or more of the aforementioned processes for determining the suggested brushing routine may be used in combination. 
     In the exemplified embodiment, after determining the suggested brushing routine, there is a determination of a brushing evaluation based on the physical property data (step  207 ). As will be discussed in further detail below, the oral care system  101  can be configured to perform a brushing evaluation of a brushing session of a user. For example, the toothbrush  103  can include sensors, and data derived from the sensors can be used to determine the motion and/or location of the toothbrush. From this determination, the system  101  can determine how well the user brushed his or her teeth. In the exemplified embodiment, this determination is based in part on the physical property data received in step  203 . For example, if a user is using a soft-bristled toothbrush, an adequate cleaning of a region may require 20 seconds of brushing. But if a user is using a hard-bristled toothbrush, an adequate cleaning of a region may require only 10 seconds of brushing. In other embodiments, other physical properties and other bases of evaluation can be utilized. For example, a shape of a brush head can inform the system  101  whether a certain brushing motion is effective, and the evaluation can be generated accordingly. 
     In the foregoing method  201 , the physical property data is used to both determine a suggested brushing routine and determine a brushing evaluation. In other embodiments, however, the physical property can be used to determine a suggested brushing routine but not to determine a brushing evaluation, or to determine a brushing evaluation but not to determine a suggested brushing routine. 
       FIG.  3 A  is a flowchart  221  showing a more detailed version of an embodiment for the process of determining a suggested brushing routine. In the process of this flowchart  221 , the suggested brushing routine is determined by adjusting an optimum brushing time based on the received physical property data to determine the brushing time for the suggested brushing routine. The optimum brushing time is predetermined from a standardized brushing routine. In certain embodiments, the standardized brushing routine may be an industry standard brushing routine in which the optimum brushing time is 2 minutes. This process begins with an input step  223  in which the physical property data is received by the data processing unit  105 . The physical property data may be received in any one or combination of several different ways as discussed herein. Following the input step  223  is an offset time determining step  225 . In this step  225 , the data processing unit  105  determines an offset time based on the input physical property data. For example, if the physical property data indicates that the bristles are extra soft, then the offset time may be a positive number. By way of another example, if the physical property data indicates that the bristles are firm, then the offset time may be a negative number. In certain embodiments, the data processing unit may communicate with a server to transmit an identifier for the toothbrush and receive in response the physical property data. 
     Following the offset time determining step  225  is a brushing time calculation step  227 . In this step  227 , the brushing time for the brushing routine is calculated. As part of this step  227 , the programmable processor  169  of the data processing unit  105  calculates the brushing time by retrieving an optimum time which is stored in the memory  171  and adding the determined offset time to the optimum time. For purposes of the process shown in this flowchart  221 , the optimum time represents an established industry standard for brushing effectiveness. As should be apparent, the offset time may increase the brushing time in excess of the optimum time, or the offset time may decrease the brushing time to be less than the optimum time. 
     After the brushing time calculation step  227  is a displaying step  229 . During this step  229 , the programmable processor  169  of the data processing unit  105  controls the display  175  to indicate to the user the determined brushing time for the suggested brushing routine. Next, the programmable processor  169  of the data processing unit  105  proceeds to an instruction step  231  in which the user is instructed to begin the suggested brushing routine. In certain embodiments, the processor  169  of the data processing unit  105  may provide other specific instructions for the brushing routine, such as the order for brushing different sections of the user’s dentiture, the length of time to brush each section, which section to start with, and the like. When the brushing time has expired, the programmable processor  169  of the data processing unit  105  proceeds to an indication step  233 , in which the user is instructed that the brushing routine is at an end. 
       FIG.  3 B  illustrates a data processing unit  105  having a user interface  175  according to one embodiment. Here, the user may input the physical property data through the user interface  175 . In such embodiments, the data processing unit  105  may present to the user using the user interface one or more questions  502 ,  506  concerning at least one physical property of the toothbrush, and then receive the physical property data as answers  504 ,  508  to the one or more questions, the answers being received by the user selecting the answers using the user interface. The questions and answers shown are merely exemplary in nature, and any of the physical properties discussed herein (as well as others) can be the subject of a question or answer on a user interface for the purposes of receiving physical property data. 
       FIG.  3 C  illustrates a data processing unit  105  whose user interface  175  can provide brushing instructions  510  for a suggested brushing routine based at least in part on the physical property data received. In this embodiment, the brushing instructions  510  comprise real-time directions for a user to follow during a brushing session. The instructions comprise an indication  514  of a region of the dentiture to brush, an indication  512  of a brushing motion, and an indication  516  of a time remaining for brushing the specified region. In this embodiment, the user interface  175  also provides an indication  518  of the total brushing time remaining in the suggested brushing routine. In this embodiment, different screens may show different instructions as the user progresses through the different stages of the brushing routine, thus coaching the user on which regions to brush, which brushing motions to use, and for how long. In other embodiments, certain indications or instructions can be omitted. Also, other indications or instructions can be added, such as an indication of whether to apply greater or lesser pressure or brushing intensity. 
     The suggested brushing routine can be determined by adjusting a preexisting brushing routine, the adjustment based at least in part on the physical property data. In other embodiments, the suggested brushing routine need not rely on a preexisting brushing routine. 
       FIG.  3 D  illustrates a data processing unit  105  whose user interface  175  can provide an evaluation of a brushing session of a user. In this embodiment, the user interface  175  provides a visualization  520  of the user’s dentiture. The dentiture can be divided into different sections, each of which the user is expected to brush during the brushing session. Brushing session data may be collected and processed according to the different portions of the dentiture. The collection of such brushing session data is described in more detail below with respect to  FIGS.  11 - 13   . 
     In the exemplified embodiment, the visualization  520  includes an indication  522  of a region of the dentiture not properly brushed. Further a recommendation  526  provides the user advice on how to improve his or her brushing. The visualization  520  also includes a performance metric  524  that indicates how well the user performed in brushing his or her teeth during the brushing session. In other embodiments, other metrics or visualizations can be used to indicate brushing performance, such as a percentage, or a number of stars (for example, three stars out of five). 
       FIG.  4    illustrates a commercial product  241  which includes a toothbrush  243  enclosed within a packaging  245 . The toothbrush  243  may be any type or style of toothbrush, whether manual or electric, and the toothbrush  243  has at least one physical property which makes it suitable for cleaning teeth. Although the toothbrush  243  is shown in the packaging  245 , the packaging  245  is not a required component for the invention. 
     The toothbrush  243  depicted includes at least one teeth cleaning element, shown in this embodiment as a plurality of bristles  247 , and both the toothbrush  243  and the packaging  245  bear an indicia  249   a - b  indicating a physical property associated with the bristles  247 . Specifically, the indicia  249   a - b  is a word descriptor indicating that the bristles  247  are ‘SOFT’. As is typical in the oral care industry, toothbrush bristles are often categorized as ‘extra soft’, ‘soft’, ‘medium’, or ‘firm’, and these categorizations represent physical properties of the bristles. The categorization of the toothbrush may be input by the user into the data processing unit  105  as the physical property data for the toothbrush. The packaging  245  also bears other indicia  249   c - d  which can be used to determine the physical property data associated with the toothbrush  247  or parts thereof. One of these indicia  249   c  is a coded image, which in this embodiment is shown as a barcode. Such a coded image may be imaged by the camera  177  of the data processing unit  105 . The coded image may provide the physical property data directly, or it may provide information about a manufacturer and/or model number to enable determination of the physical property data. In certain embodiments, the coded image may be a quick response (QR) code. The other of these indicia  249   d  is an alphanumeric product identifier, which may also provide information about a manufacturer and/or model number. 
     The indicia  249   a - d  may be any type of identifying mark which directly or indirectly represent the at least one physical property of the toothbrush  243  and from which the physical property data may be determined. For indirect representation, the indicia  249   a - d  may enable the physical property data to be obtained by reference to information stored in the memory  171 , from the server  107 , or from any public source or database. In certain embodiments, the indicia  249   a - d  may represent a plurality of physical properties of the toothbrush  243 , and the physical properties may be any associated with the toothbrush  243 . 
     A toothbrush  251  having at least one physical property is illustrated in  FIG.  5   . The at least one physical property may be, for example, the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the angle of the head with respect to the handle, the flexibility of the material from which the toothbrush is constructed, the head size, the size of the handle, the presence of an elastomeric element in the bristle field, the mobility of the head of the toothbrush with respect to the handle of the toothbrush, the mobility of a first portion of the head with respect to a second, different portion of the head, and the like. This toothbrush  251  includes a handle  253  coupled to a head  255  and a radio frequency identifier (RFID) tag  257  positioned on the back side  259  of the head  255 . The RFID tag  257  may be detected and by an RFID tag reader  179  included as part of the data processing device  105 . In certain embodiments, the RFID tag  257  may store the physical property data and transfer the physical property data to the data processing device  105  when communicating with the RFID tag reader  179 . In other embodiments, the RFID tag  257  may communicate an identifier for the toothbrush  251  from which the data processing unit  105  may obtain the physical property data. In such embodiments, the physical processing data may be retrieved from the memory  171 , the server  107 , or any public source or database using the identifier for the toothbrush  251 . Through such processes, the physical property data will be indicative of the at least one physical property of the toothbrush  251 . 
     A toothbrush  261  having at least one physical property is illustrated in  FIG.  6   . The at least one physical property may be, for example, the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the angle of the head with respect to the handle, the flexibility of the material from which the toothbrush is constructed, the head size, the size of the handle, the presence of an elastomeric element in the bristle field, the mobility of the head of the toothbrush with respect to the handle of the toothbrush, and the like. This toothbrush  261  includes a head  263  coupled to a handle  265 , and the handle  265  includes at least one identifying feature  267 . In certain embodiments, the at least one identifying feature  267  may be a decorative feature formed as a pattern, one or more different colors, a profile shape of the toothbrush, and the like. In certain embodiments, the at least one identifying feature  267  may be a distinct look resulting from implementation of a functional feature, such as the bristle pattern, the bristle profile, the presence of a textured grip on the handle  265 , and the like. In still other embodiments, the at least one identifying feature  267  may be a combination of a decorative feature and distinct look resulting from implementation of a functional feature. In addition, the at least one identifying feature  267  may be formed on any separate part of the toothbrush  261 , or it may extend across multiple parts of the toothbrush  261 . In certain embodiments, the identifying feature may be identified by imaging part or all of the toothbrush  261  with the camera  177  of the data processing unit  105  and processing the image with image recognition software on the programmable processor  169  to identify the identifying feature  267 . Once the identifying feature  267  is identified, then the programmable processor  169  may use the identification to retrieve the physical property data from the memory  171  or to obtain the physical property data from the server  107 . The physical property data will therefore be indicative of the at least one physical property of the toothbrush  261 . 
     A toothbrush  271  having at least one physical property is illustrated in  FIG.  7   . This toothbrush  271  includes a head  273  coupled to a handle  275 , and the handle  275  includes cavity  277  from which an oral care additive  279  may be dispensed for use during a brushing session. The manner in which the oral care additive  279  is dispensed is not limiting of the invention. The toothbrush  271  may include indicia, an RFID tag, an identifying feature, or the like, which is indicative of the presence of the oral care additive  279 . When the user prepares to perform a brushing routine, the data processing unit  105  may receive the physical property data as input from the user, using the camera  177 , using the RFID tag reader  179 , or any other input method, such that the physical property data reflects the presence of the oral care additive  279 . 
     An electric toothbrush  281  is illustrated in  FIG.  8   . The electric toothbrush  281  includes a handle  283  and a refill head  285 . In certain embodiments, the handle  283  and the refill head  285  are removably coupled to each other. In certain embodiments, the at least one physical property is associated with the refill head  285 . The at least one physical property associated with the refill head  285  may be, for example, the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the head size, the presence of an elastomeric element in the bristle field, the presence of a tongue cleaner, and the like. In certain embodiments, the at least one physical property is associated with the handle  283 , such as the presence of an electrically-powered vibratory element. In certain embodiments of electric toothbrushes, the control circuit  165  of the data processing unit  105  may reside at least partially within the handle  283 . Alternatively, the handle  283  may include a separate toothbrush control circuit which controls the electric toothbrush and communicates with the data processing unit  105 . 
     In this embodiment of electric toothbrush, the refill head  285  includes a bristle field  287  which includes at least one elastomeric element  289  and a tongue cleaner  291  on the back side  292  of the refill head  285 . In addition, the bristle field  287  has a bristle profile  293  formed by having bristles of differing lengths. Any one or more of the presence of the at least one elastomeric element  289  in the bristle field  287 , the presence of the tongue cleaner  291 , and the bristle profile  293  may be reflected in the physical property data. Also in this embodiment, shown schematically, the handle includes a motor  294  operably coupled to a shaft  295 , with an eccentric mass  297  positioned at the distal end of the shaft  295 . In combination, the motor  294 , the shaft  295 , and the eccentric mass  297  form an electrically-powered vibratory element, the presence of which may be reflected in the physical property data. In addition, the physical property data associated with the electric toothbrush  281  may reflect any one or more physical properties of one or both of the handle  283  and the head  285 . 
     A refill head  301  having at least one physical property is illustrated in  FIG.  9   . The refill head  301  may be removably coupled to a handle as shown in  FIG.  8   . The at least one physical property may be, for example, the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the head size of the toothbrush, and the like. As shown, the refill head  301  includes an RFID tag  305  positioned on the back side  303  of the head  301 . In the same manner discussed above, the RFID tag  305  may be detected and by an RFID tag reader  179  included as part of the data processing device  105  so that the physical property data will be indicative of the at least one physical property of the refill head  301 . 
     Portions of a handle  311  coupled to a refill head  313  for an electric toothbrush are illustrated in  FIG.  10   . The handle  311  and the refill head  313  include a physical interface which is used to help generate the physical property data. The refill head  313  includes at least one physical property which may have an impact on the effectiveness of a brushing routine. In this embodiment of electric toothbrush, the control circuit  165  of the data processing unit  105  may reside at least partially within the handle  311 . Alternatively, the handle  311  may include a separate toothbrush control circuit which controls the electric toothbrush and communicates with the data processing unit  105 . The combination of the refill head  313  coupled to the handle  311  provides a selection mechanism which may be used to identify the refill head  313 , and from this identification the data processing unit  105  may obtain the physical property data. In certain embodiments, the selection mechanism may directly identify the at least one physical property of the refill head  313 . In other embodiments, the selection mechanism may identify the refill head  313 , and from identification of the refill head  313 , the data processing unit  105  may obtain the physical property data. In both types of embodiments, the physical property data will be indicative of the at least one physical property of the refill head  313 . 
     As part of the selection mechanism, the refill head  313  includes a plurality of selection indicator features  315 , which are shown as a plurality of teeth, and the handle  311  includes a plurality of selection identifiers  317 , which are shown as a plurality of switches. Each selection identifier  317  is located within one of a plurality of receptacles  319 , each of which is formed to receive one of the selection indicator features  315 . Each selection identifier  317  helps the data processing unit  105  determine which, if any, of the selection identifiers  317  of the handle  311  are interacting with one of the selection indicator features  315  of the refill head  313  when the refill head  313  is coupled to the handle  311 . By identifying which of the selection identifiers  317  are interacting with the selection indicator features  315 , the data processing unit  105  can either identify the refill head  313 , and with identification of the refill head obtain the physical property data, or directly receive the physical property data of the refill head  313 . 
       FIG.  11    illustrates a toothbrush  341  which includes at least one physical property which may have an impact on the effectiveness of a brushing routine. The at least one physical property may be the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the angle of the head with respect to the handle, the flexibility of the material from which all or a part of the toothbrush is constructed, the head size of the toothbrush, the size of the handle, the presence of an elastomeric element in the bristle field, the presence of a tongue cleaner, the mobility of the head of the toothbrush with respect to a handle of the toothbrush, the mobility of a first portion of the head with respect to a second, different portion of the head, and the like. The handle  343  of the toothbrush  341  forms a housing for containing electronic circuitry  351  for collecting brushing session data. The handle  343  is a hollow structure in which a cavity  345  is formed. The electronic circuitry  351 , which includes a power source  352 , is located within the cavity. The electronic circuitry  351  may be used to collect and analyze brushing session data from which an evaluation of the brushing session may be made. In certain embodiments, the evaluation of the brushing session may be based at least in part upon the physical property data. 
     A schematic version of the electronic circuitry  351  is shown in  FIG.  12   . The electronic circuitry  351  includes a processor  353  communicably coupled to sensors  355 , a memory  357 , and a communication module  359 . The number of sensors  355  included as part of the electronic circuitry  351  depends upon the type of brushing session data to be detected and the functionality of each type of sensor employed. The brushing session data that is detected and collected may include position, motion, acceleration, frequency, and pressure against the surface of the teeth. Other types of brushing session data associated with a brushing session may also be detected and collected, and those listed herein are not to be limiting of the invention unless otherwise indicated in the claims. In certain embodiments, only one sensor  355  may be included as part of the electronic circuitry  351 , and in other embodiments, two or more sensors  355  may be included. By way of example, the at least one sensor  355  may be any one or more of the following: a 3-axis accelerometer, a 6-axis accelerometer, a gyroscope, a magnetometer, a pressure sensor, among other types of sensors. In general, each sensor  355  included as part of the electronic circuitry  351  generates at least part of the brushing session data. For purposes of the present disclosure, the term “brushing session data” is any type of information which may be extracted or derived from a sensor or sensor signal, regardless of the form of the extracted information. By way of example, brushing session data may be in the form of mathematical data (such as a formula which mathematically represents at least part of the sensor signal), analog data (such as the waveform of the sensor signal), and/or digital data (such as a representation of at least part of the sensor signal in a digital format). In certain embodiments, the processor  353  and the memory  357  may be omitted from the electronic circuitry  351  of the toothbrush  341 . In such embodiments, the sensors  355  may communicate brushing session data directly to the communication module for transmission. 
     The memory  357  may be any appropriate type of memory or storage which enables the processor  353  to perform the desired programming, such as volatile and/or non-volatile random access memory, or any other type of storage. The particular type of storage used for the memory  357  is not to be limiting of the invention. The communication module  359  in the exemplary embodiment includes an antenna  361  to enable wireless communication. The communication module  359  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, BluetoothⓇ, and the like, or it may communicate using any type of proprietary wireless transmission protocol. In certain embodiments, the communication module  359  may include a port to enable communications using wires and wired protocols, such as USB and the like. The particular mode of communication used by the communication module is not limiting of the invention unless specifically set forth in a claim. 
       FIG.  13    illustrates another toothbrush  381  which may be used with a dongle  391  to detect and collect brushing session data. The toothbrush  381  also includes at least one physical property which may have an impact on the effectiveness of a brushing routine. The at least one physical property may be the bristle hardness, the bristle pattern, the bristle profile, the type of teeth cleaning element or elements, the angle of the head with respect to the handle, the flexibility of the material from which all or a part of the toothbrush is constructed, the head size of the toothbrush, the size of the handle, the presence of an elastomeric element in the bristle field, the presence of a tongue cleaner, the mobility of the head of the toothbrush with respect to a handle of the toothbrush, and the like. Generally, the toothbrush  381  includes a handle  383  and a head  385  to which a plurality of teeth cleaning elements  387  are affixed. The dongle  391  may be removably affixed to the proximal end  389  of the handle  383 . The dongle  391  comprises a housing for containing electronic circuitry  393  and an associated a power source  395 , which may be similar to that described above in connection with  FIG.  12   . 
     The brushing session data which is detected and collected by the toothbrush embodiments shown in  FIGS.  11  and  13    may include a side-to-side linear brush stroke motion, an up and down linear brush stroke motion, a circular brush stroke motion, a flicking brush stroke motion, a brush stroke rate, and a pressure of the head of the toothbrush on the teeth, amongst others. During use, the brushing session data is generated during at least a portion of the brushing session. The brushing session data may be used to evaluate the brushing session by calculating one or more performance metrics, and the performance metric may represent brushing efficacy during one or more portions of the brushing session. The performance metric may express the efficacy of a brushing session, or even for portions of a brushing session, as a single number, and stored in the memory  171  of the data processing unit  105  for later use. In certain embodiments, the data processing device  105  may transmit the calculated performance metrics to the server  107  for storage and or additional analysis. In certain embodiments, a base performance metric may be weighted, using one or more of the physical properties of the toothbrush used during the brushing session from which the data underlying the performance metric was obtained, to calculate a weighted performance metric. For example, when a user brushes their teeth using a toothbrush with a large head, the performance metric may be given a greater weight as compared to when a toothbrush with a smaller head is used. Similarly, when a user brushes their teeth using a toothbrush which dispenses an oral care additive, the performance metric may be given a greater weight as compared to when a toothbrush is used that does not dispense an oral care additive. The weights given to the different physical properties may vary by the type of physical property and the amount it is determined that physical property improves or decreases the efficacy of a user’s brushing routine. 
     In certain embodiments, the performance metrics which are stored in the memory  171  of the data processing unit  105  or on the server  107  may be used during future brushing sessions to aid in determining what brushing routine to suggest to the user. For example, in the context of the process shown in the flowchart  221  of  FIG.  3 A , performance metrics may be used in combination with the physical property data to help determine the target brushing time for a brushing routine. Also, in embodiments in which performance metrics are stored, the performance metrics may be analyzed by machine learning processes, and the machine learning may be used to enhance future brushing routines. 
       FIG.  14 A  illustrates an oral care system  1101  in accordance with an embodiment of the present invention. The oral care system  1101  includes a toothbrush  1103  and a data processing unit  1105 . The data processing unit  1105  may communicate with a server  1107  for purposes of storing larger amounts of data or to provide server-side processing functionality. The presence of the server  1107  and communication between the data processing unit  1105  and the server  1107 , however, are not limiting of the present invention, unless specifically set forth in a claim. 
     The toothbrush  1103  generally includes a handle  1111 , a neck  1113 , and a head  1115 . The neck  1113  extends between the handle  1111  and the head  1115  and connects the head  1115  to the handle  1111 . The handle  1111  provides the user with a mechanism by which the toothbrush  1103  can be readily gripped and manipulated during a brushing routine. The handle  1111  may be formed of many different shapes, sizes and materials and may be formed by a variety of manufacturing methods that are well-known to those skilled in the art. The handle  1111  extends from a proximal end  1117  to a distal end  1119  along a longitudinal axis A to form an elongated gripping portion  1123  therebetween. The handle  1111  transitions into the neck  1113  at the distal end  1119 . While the neck  1113  generally has a smaller transverse cross-sectional area than the handle  1111 , the invention is not so limited. Broadly speaking, the neck  1113  forms a transition region between the handle  1111  and the head  1115 , with the head  1115  extending from an end of the neck  1113   opposite the handle  1111 . While the head  1115  is normally widened relative to the neck 11113, in some embodiments the head  1115  can simply be a continuous extension or narrowing of the neck  1113  and/or handle  1111 . The head  1115  extends from a proximal end  1125  to a distal end  1127  along a z-axis. In the exemplary embodiment, the z-axis is parallel to the longitudinal axis A. In certain embodiments, the z-axis may be placed at an angle to the longitudinal axis A. 
     In the exemplary embodiment, the handle  1111  includes a suitable textured grip  1129  made of a soft elastomeric material. The textured grip  1129  may cover or form at least a portion of a front surface  1131  and a rear surface  1133  of the handle  1111 . The textured grip  1129  may also extend to a rear surface  1135  of the neck  1113  and to a rear surface  1137  of the head  1115 . The handle also includes a removable end cap  1139  which enables access into a cavity  1141  formed within the handle  1111 . 
     In embodiments in which a portion of the front surface  1131  of the handle  1111  is also covered by or formed from the material of the textured grip  1129 , the textured grip  1129  may form part of or cover an electrical switch  1143 , which is operable between an open state and a closed state. The open and closed states of the electrical switch  1143  serve to disconnect and connect, respectively, electric power to electronic circuitry (described below) within the cavity  1141  of the handle  1111 . In certain embodiments, the electrical switch  1143  may be a single button which alternates between the open and closed states. In alternative embodiments, the electrical switch  1143  may include multiple buttons which serve to control the switch between the open and closed states. Of course, other types of switches may be used in conjunction with the toothbrush  1103  for activating and deactivating the electronic circuitry within the cavity  1141  of the handle  1111 , including without limitation slide switches, toggle switches, motion activated switches, photosensitive switches, sound-activated switches, electronic switches, and/or combinations thereof. 
     The electrical switch  1143  may form one or more minor protrusions in the front surface  1131  of the handle  1111  for easy manipulation by a user. Specifically, when a user holds the toothbrush  1103  in a normal fashion, the user’s thumb will be positioned adjacent the electrical switch  1143  to easily enable the user to actuate the electrical switch  1143  between the open and closed states as desired. Of course, the invention is not so limited and the electrical switch  1143  may be otherwise located on the handle  1111 , the neck  1113  or elsewhere on the toothbrush  1103 . 
     The handle  1111 , the neck  1113 , and the head  1115  may be formed as separate components which are operably connected at a later stage of the manufacturing process by any suitable technique known in the art, including without limitation thermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve, threaded engagement, adhesion, or fasteners. However, in other embodiments, the handle  1111 , the neck  1113 , and the head  1115  of the toothbrush  1103  may be formed as a single unitary structure using a molding, milling, machining or other suitable process. Whether the handle  1111 , the neck  1113 , and the head  1115  are of a unitary or multi-piece construction (including connection techniques) is not limiting of the present invention, unless specifically set forth in a claim. In some embodiments of the invention, the head  115  may be detachable (and replaceable) from the handle  1111  and/or from the neck  1113  using techniques known in the art. 
     The head  1115  generally includes a front surface  1145 , the rear surface  1137  and peripheral side surfaces  1147  that extend between the front and rear surfaces  1145 ,  1137 . The front surface  1145  and the rear surface  1137  of the head  1115  can take on a wide variety of shapes and contours, none of which are limiting of the present invention. For example, the front and rear surfaces  1145 ,  1137  can be planar, contoured or combinations thereof. 
     The front surface  1145  of the head  1115  includes a collection of at least one teeth cleaning element, shown in the exemplary embodiment as a plurality of bristles  1149 , extending therefrom for cleaning teeth surfaces. As used herein, the term “teeth cleaning element” is used in a generic sense to refer to any structure that can be used to clean or polish the teeth through relative surface contact. In certain embodiments, the head  1115  may include a single teeth cleaning element, and in other embodiments, the head  1115  may include two or more teeth cleaning elements. Common examples of the at least one teeth cleaning element include, without limitation, bristle tufts, filament bristles, fiber bristles, nylon bristles, spiral bristles, rubber bristles, elastomeric protrusions, flexible polymer protrusions, combinations thereof and/or structures containing such materials or combinations. Suitable elastomeric materials include any biocompatible resilient material suitable for uses in an oral hygiene apparatus. To provide optimum comfort as well as cleaning benefits, the at least one teeth cleaning element may be an elastomeric material having a hardness property in the range of A8 to A25 Shore hardness. Other materials within and outside the noted hardness range may also be used. 
     The bristles  1149  of the present invention can be connected to the head  1115  in any manner known in the art. For example, staples/anchors, in-mold tufting (IMT) or anchor free tufting (AFT) could be used to mount the bristles  1149  of the exemplary embodiment. In AFT, a plate or membrane is secured to the brush head such as by ultrasonic welding. The bristles extend through the plate or membrane. The free ends of the bristles on one side of the plate or membrane perform the cleaning function. The ends of the bristles on the other side of the plate or membrane are melted together by heat to be anchored in place. Alternatively, the bristles may be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles are mounted within or below the tuft blocks. 
     Referring to  FIG.  14 B , the handle  1111  is a housing for containing electronic circuitry  1151  and a power source  1152 . The handle  1111  is a hollow structure in which the cavity  1141  is formed. More specifically, in the exemplified embodiment, the cavity  1141  is formed in the elongated gripping portion  1123  of the handle  1111 . In the exemplary embodiment, the power source  1152  is shown as two batteries located within the cavity  1141 . Of course, the invention is not so limited and more or fewer than two batteries may be used, or alternatively, other types of power sources may be used. A removable end cap  1139  forms the proximal end  1117  of the handle  1111  by engagement with the gripping portion  1123  of the handle  1111 . In the exemplary embodiment, the end cap  1139  may threadably engage the gripping portion  1123  of the handle  1111 . In other embodiments, the end cap  1139  may engage the gripping portion  1123  of the handle  1111  by snap engagement or by any other mechanical locking engagement. Removal of the end cap  1139  exposes an opening  1159  which forms a passageway into the cavity  1141  through which the power source  1152  can be inserted into and removed from the cavity  1141 . Access to the cavity may be formed in other ways in other embodiments. For example, the handle  1111  may include a sliding panel which is removable to form an elongated opening along the longitudinal axis A of the handle  1111  (e.g., the front surface, the rear surface and/or the side surfaces) to provide access to the cavity  1141 . Prior to use, a user may insert the power source  1152  through the opening  1159  and into the cavity  1141  in the elongated gripping portion  1123  of the handle  1111 , and the cavity  1141  is enclosed by replacing the end cap  1139 . 
     The electronic circuitry  1151  which may be included in an exemplary toothbrush  1103  is shown in  FIG.  14 C . The electronic circuitry  1151  includes a processor  1153  communicably coupled to sensors  1155 , a memory  1157 , and a communication module  1159 . The number of sensors  1155  included as part of the electronic circuitry  1151  depends upon the types of physical properties to be detected and the functionality of each type of sensor employed. Physical properties may include position, motion, acceleration, frequency, and pressure against the surface of the teeth. Other types of physical properties associated with a brushing routine may also be detected, and those listed herein are not to be limiting of the invention unless otherwise indicated in the claims. In certain embodiments, only one sensor  1155  may be included as part of the electronic circuitry  1151 , and in other embodiments, two or more sensors  1155  may be included. By way of example, the at least one sensor  1155  may be any one or more of the following: an accelerometer, a gyroscope, a magnetometer, a pressure sensor, among other types of sensors. While the functionality of certain types of sensors will be discussed in greater detail below, in general each sensor  1155  included as part of the electronic circuitry  1151  generates a sensor signal which includes sensor data that corresponds to the physical property detected by the sensor. For purposes of the present disclosure, the term “sensor data” is any type of information which may be extracted or derived from the sensor or sensor signal, regardless of the form of the extracted information. By way of example, sensor data may be in the form of mathematical data (such as a formula which mathematically represents at least part of the sensor signal), analog data (such as the waveform of the sensor signal), and/or digital data (such as a representation of at least part of the sensor signal in a digital format). In certain embodiments, the processor  1153  and the memory  1157  may be omitted from the electronic circuitry  1151  of the toothbrush  1103 . In such embodiments, the sensors  1155  may communicate sensor data directly to the communication module for transmission. 
     The memory  1157  may be any appropriate type of memory or storage which enables the processor  1153  to perform the desired programming, such as volatile and/or non-volatile random access memory, or any other type of storage. The particular type of storage used for the memory  1157  is not to be limiting of the invention. The communication module  1159  in the exemplary embodiment includes an antenna  1161  to enable wireless communication. The communication module  1159  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, BluetoothⓇ, and the like, or it may communicate using any type of proprietary wireless transmission protocol. In certain embodiments, the communication module  1159  may include a port to enable communications using wires and wired protocols, such as USB and the like. The particular mode of communication used by the communication module is not limiting of the invention unless specifically set forth in a claim. 
     Referring to both  FIGS.  14 A and  1 D , the data processing unit  1105  includes a housing  1163  and electronic circuitry  1165 , with the housing enclosing and/or supporting the various components of the electronic circuitry  1165 . The electronic circuitry  1165  is coupled to a power source  1167 , shown as a battery in the exemplary embodiment. Of course, the invention is not so limited, and other types of power sources may be used. The electronic circuitry  1165  includes a processor  1169  communicably coupled to a memory  1171 , a communication module  1173 , and a display  1175 . In certain embodiments, the electronic circuitry  1165  may include other components, such as a speaker to provide audible feedback to the user, one or more buttons to receive input from the user, and one or more ports for making a wired connection between the electronic circuitry  1165  and other circuitry external to the data processing unit  1105 . In certain other embodiments, the data processing unit  1105  may be a smartphone, a tablet computer, a laptop computer, and the like, although the invention is not so limiting. 
     The memory  1171  may be any appropriate type of memory or storage which enables the processor  1169  to perform the desired programming, such as volatile and/or non-volatile random access memory. The particular type of storage used for the memory  1171  is not to be limiting of the invention. 
     The display  1175  may be any type of light emitting display, and as shown in the exemplary embodiment, the display  1175  may be an LED panel. In certain other embodiments, the display  1175  may be an LCD panel, an OLED panel, or any other type of display which is electronically controllable by the processor  1169  to provide visual feedback to the user. In certain embodiments, the display  1175  may be a touch sensitive display which accepts input from the user directly on the display surface. The type and configuration of the display  1175  is not limiting of the invention unless specifically set forth in a claim. 
     The communication module  1173  includes an antenna  1179  to enable wireless transmission. The communication module  1173  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, BluetoothⓇ, and the like, or it may communicate using any type of proprietary wireless transmission protocol. The mode of communication for which the communication module  1173  is configured is not limiting of the invention unless specifically set forth in a claim. In certain embodiments, the communication module  1173  may include a port to enable communications using wires and wired protocols, such as USB and the like. For proper functioning of the exemplary embodiment, the communication module  1159  of the toothbrush  1103  and the communication module  1173  of the data processing unit  1105  communicate with each other, whether such communications are wireless or wired, using the same communication protocol. 
     The communication module  1173  of the data processing unit  1105  may also be configured and/or programmed to communicate with the server  1107 . The communication module  1173  may communicate with the server  1107  over any combination of public and/or private network, and the communications may be wired, wireless, or a combination of the two. In certain embodiments, the communication module  1173  may communicate with the server  1107  over the Internet using one or more types of communication protocols. In certain embodiments, the server  1107  may be programmed with an application programming interface (API) which provides server-side functionality to the data processing unit  1105 . 
     In the exemplary embodiment, the processor  1153  of the toothbrush  1103  may be programmed with functionality to analyze the sensor data generated by the sensors  1155 . Similarly, the processor  1169  of the data processing unit  1105  may be programmed with functionality to analyze the sensor data generated by the sensors  1155 . In the ensuing description, the disclosed processes may be partially or wholly performed by one or both of the processor  1153  of the toothbrush  1103  and the processor  1169  of the data processing unit 11105 through programming provided to each respective processor  1154 ,  1169 . In certain instances, where expressly indicated, the disclosed processes may be limited to programming on one of the processor  1153  of the toothbrush  1103  or the processor  1169  of the data processing unit  1105 . 
     An alternative embodiment for an oral care device  1181  which may be incorporated into the oral care system  1101  is shown in  FIG.  15   . In this alternative embodiment, the oral care device  1181  includes a toothbrush  1183  which is generally formed by a handle  1185 , a neck  1187 , and a head  1189 . The front surface  1191  of the head  1189  includes at least one teeth cleaning element, shown as a plurality of bristles  1193 , extending therefrom for cleaning teeth surfaces. The oral care device  1181  also includes a dongle  1195  which may be removably coupled to the proximal end  1197  of the handle  1185 . The dongle  195  is a housing for containing electronic circuitry  1199  and an associated a power source  1201 , which may be the same as described above in connection with  FIG.  14 C . In the exemplary embodiment, the dongle  1195  includes indicia  1203  on one side thereof to indicate to the user the orientation of the dongle with respect to the bristles  1193 . Since the dongle  1195  is removable from the handle  1185 , the analysis of sensor data and feedback to the user during a brushing routine, which are described in greater detail below, are facilitated by having the dongle  1195  coupled to the handle  1185  in a predetermined orientation. 
       FIGS.  16 A-D  illustrate four different types of brush stroke motions for the head  1115  of the toothbrush  1103  which may be detected during a brushing routine. In certain embodiments, each of these brush stroke motions may be detected through use of an accelerometer. In certain embodiments, brush stroke motions may be detected through use of a 3-axis accelerometer used in combination with a 3-axis gyroscope. The first brush stroke motion, illustrated by the arrow  1211  in  FIG.  16 A , is a side-to-side linear brush stroke motion that is aligned parallel to the z-axis of the head  1115  of the toothbrush  1103 . Using an accelerometer, this brush stroke motion may be detected as a linear acceleration along the z-axis. As indicated above, the z-axis in the exemplary embodiment is parallel to the longitudinal axis A of the handle (see  FIG.  14 A ). The y-axis, for purposes of this disclosure, is defined as being perpendicular to the z-axis and parallel with at least a portion of the front surface  1145  of the head  1115 . The x-axis, for purposes of this disclosure, is defined as being orthogonal to the plane formed by the y- and z-axes. Generally speaking, the at least one teeth cleaning element may extend from the front surface  1145  of the head  1115  substantially in the direction the x-axis, although the at least one teeth cleaning element need not be parallel to the x-axis. Of course, any coordinate system may be used to define the brush stroke motions of the head  1115  of the toothbrush  1103  while still staying within the spirit and scope of the invention. 
     The second brush stroke motion, illustrated by the arrow  1213  in  FIG.  16 B , is an up and down linear brush stroke motion that is aligned parallel to the y-axis of the head  1115  of the toothbrush  1103 . Using an accelerometer, this brush stroke motion may be detected as a linear acceleration along the y-axis. The third brush stroke motion, which is illustrated by the arrow  1215  in  FIG.  16 C , is a quasi-circular brush stroke motion that moves within a plane parallel to both y-axis and the z-axis. Using an accelerometer, this brush stroke motion is detected as a linear acceleration along the z-axis simultaneous with a linear acceleration along the y-axis with a phase shift between the y and z motions. In certain embodiments, quasi-circular brush stroke motion may be defined as having linear accelerations along both the y- and z-axes which exceeds a predetermined acceleration threshold or which differ by less than a predetermined amount. By way of example, a quasi-circular brush stroke motion may be defined as any simultaneous linear acceleration over 1 m/s2 along each of the y- and z-axes. By way of another example, a quasi-circular brush stroke motion may be defined as any simultaneous linear acceleration along both the y- and z-axes which differs by less than 0.5 m/s2. By way of a third example, a quasi-circular brush stroke motion may be defined in terms of the eccentricity of the ellipse described by the brushing motion, where an eccentricity of 0 corresponds to a perfect circle. In all cases, a linear brush stroke motion along either axis which falls outside of the predefined bounds of quasi-circular brush stroke motion may be identified as linear acceleration along the respective y- or z-axis. The fourth brush stroke motion, which is illustrated by the arrow  1217  in  FIG.  16 D , is a flicking brush stroke motion which is rotation about the z-axis. This brush stroke motion may be detected using a gyroscope as a rotational acceleration about the z-axis. 
       FIGS.  17 - 19    illustrate examples of sensor signals from which sensor data may be extracted and used to identify certain different types of brush stroke motion.  FIG.  17    illustrates a graph  1219  showing a sensor signal from an accelerometer as a combination of a y-axis acceleration signal  1221  and a z-axis acceleration signal  1223  over time. As can be seen from the overlaid y- and z-axis acceleration signals, the two acceleration signals exhibit a relative phase shift as compared to one another, and this relative phase shift may form sensor data used to identify brush stroke motion. Each acceleration signal indicates a linear brush stroke motion along the respective y- and z-axes. The amount of the phase shift between two respective acceleration signals may be used to determine whether a particular brush stroke motion is interpreted to be a quasi-circular brush stroke motion. Although whether a particular phase shift present in a brush stroke motion is interpreted as quasi-circular motion may also depend upon any established thresholds for the amount of phase shift. For example, a perfectly circular brushing motion exhibits a 90° phase shift between the two acceleration signals. In certain embodiments, it may be desirable or convenient to define a quasi-circular brushing motion as 90°±φ, where φ represents the predetermined threshold. In such embodiments, φ may be 1°-45°, and in still other embodiments, φ may be greater than 45°. In addition to phase, in certain embodiments, the amplitudes of the two acceleration signals may be used as a factor when determining whether a particular brush stroke is interpreted to have a quasi-circular brush stroke motion. For example, if the differences between amplitudes of the two acceleration signals is greater than a predetermined threshold value, then it may be desirable to determine that the underlying brush stroke motion does not qualify as a quasi-circular brush stroke motion, whereas acceleration signals which have differences between amplitudes less than the predetermined threshold are determined to represent a quasi-circular brush stroke motion. Alternatively, or in addition, in certain other embodiments, if one or both of the acceleration signals falls below a predetermined threshold, then it may be desirable to determine that the underlying brush stroke motion does not qualify as a quasi-circular brush stroke motion, whereas acceleration signals which extend above the predetermined threshold are determined to represent a quasi-circular brush stroke motion. 
       FIG.  18    illustrates a graph  1225  which shows a plot of a y-axis acceleration signal against a z-axis acceleration signal. This graph  1225  is an example of how the acceleration signals along the y- and z-axes may be interpreted as sensor data showing a quasi-circular brush stroke motion even though the actual motion is in fact not perfectly circular. The roughly elliptical brush stroke motion  1227  in the graph  1225  may be interpreted as a quasi-circular brush stroke motion because the overall phase shift between the two acceleration signals is greater than a predetermined threshold. As indicated above, other factors could be applied to the data shown in the graph  1225  to determine which data should be included or excluded from the determination of whether a particular brush stroke motion qualifies as a quasi-circular brush stroke motion. 
       FIG.  19    illustrates a graph  1229  showing a sensor signal from a gyroscope as a combination of acceleration signals generated from rotation about x-, y- and z-axes. This graph  1229  shows an acceleration signal  1231  resulting from rotation about the z-axis that is greater than the acceleration signals  1233 ,  1235  resulting from rotation about the x- and y- axes. The z-axis acceleration signal  1231  may form sensor data used to identify a flicking brush stroke motion. While all of the x-, y-, and z-axis acceleration signals  1231 ,  1233 ,  1235  are indicative of rotation about the respective axis, the acceleration signal  1231  resulting from rotation about the z-axis is indicative of a flicking motion. 
     A brushing profile graph  1241  illustrating the proportion of different types of brush stroke motion over time during a brushing routine is shown in  FIG.  20   . An entire brushing routine is shown in the brushing profile graph  1241 , and in this instance the brushing routine lasted for 1120 sec. In practice, a brushing routine may be longer or shorter than 1120 sec, as each brushing routine has a time length, as explained in greater detail below, which is adjusted to account for the user’s brushing habits. This brushing profile graph  1241  shows how the brushing profile of a brushing routine may be viewed as a composite of different types of brush stroke motions. The different types of brush stroke motions shown are a quasi-circular brush stroke motion  1243  (in the plane of the y- and z-axes), an up and down brush stroke motion  1245  (in the direction of the y-axis), a forward and backward brush stroke motion  1247  (in the direction of the z-axis), and a flicking brush stroke motion  1249  (rotation about the z-axis). In the brushing profile graph  1241 , the up and down brush stroke motion  1245  and the forward and backward brush stroke motion  1247  are those parts of the acceleration signal during a brushing routine in which one and/or the other falls below the threshold for the brush stroke motion to be identified as a quasi-circular brush stroke motion. One technique that may be used to generate the brushing profile graph  1241  is, after the brush stroke motions have been identified, integrate the portion of the sensor signal from which each particular brush stroke motion was identified to generate sensor data, apply a normalization factor to the sensor data, and then use the resulting normalized sensor data to determine the proportion of each brush stroke motion over time during the brushing routine. The normalization factors may vary based on the implementation and brushing philosophy. For example, according to the traditional brushing philosophy that circular brush strokes are best, quasi-circular brush strokes may be normalized to have a greater weight as a percentage of the brushing profile. 
     A flowchart  1261  showing an exemplary process for at least a portion of brushing routine is shown in  FIG.  21   . The process of this flowchart  1261  serves to determine and adjust a target brushing time of a brushing routine based upon a determined brush stroke motion during the brushing routine, and the process may be implemented as programming for one or more processors. As should be appreciated, the target brushing time may be determined by processes different or varying from this exemplary process, such that the invention is not to be limited by the exemplary process. For convenience, as part of the description below, reference will also be made to the hardware components discussed above in  FIGS.  14 A-D . An initiation step  1263  starts off the brushing routine, and this initiation step  1263  may be achieved by the user pressing a button on one of the toothbrush  1103  or on the data processing unit  1105 . Using the toothbrush  1103 , in certain embodiments, the initiation step  1263  may be achieved by the user actuating the electrical switch  1143 . On the data processing unit  1105 , in certain embodiments, the initiation step may be achieved by first pressing the electrical switch  1143  on the toothbrush  1103  to power the electrical circuitry  1151  of the toothbrush  1103  and then pressing a button on the data processing unit  1105 , or if the data processing unit  1105  includes a touch sensitive display, pressing a virtual button shown on touching the display  1175 . 
     As part of the initiation step  1263 , the user begins the brushing routine. In certain embodiments, the data processing unit  1105  may direct the user to follow a predetermined sequence for the brushing routine, starting the brushing routine by brushing a predetermined section of the dentiture of the user and then continuing to other sections of the dentiture according to the predetermined sequence. In other embodiments, in which the toothbrush  1103  has appropriate tracking sensors and the data processing unit  1105  is able to determine which sections of the dentiture are being brushed, regardless of sequence, the data processing unit may direct the user to start the brushing routine by first brushing a predetermined section of the dentiture and then tracking which sections are being brushed and for how long each is brushed during the brushing routine. In still other embodiments, the user may provide input to the data processing unit to indicate the section of the dentiture that will be brushed during the first portion of the brushing routine and during each subsequent portion of the brushing routine. 
     Following the initiation step  1263  is a sensor data generating step  1265  which is performed by the electronic circuitry  1151  of the toothbrush  1103 . During this step  1265 , the sensors  1155  included in the toothbrush  1103  sense the physical properties each is configured to detect and generate sensor data accordingly as the brushing routine begins and continues. Next is the brush stroke motion determination step  1267 . In this step  1267 , the sensor data is analyzed to determine the type or types of brush stroke motion for the first and/or current portion of the brushing routine. In other words, the sensor data may be analyzed in real time. In the exemplary embodiment, the sensor data is analyzed at least for a quasi-circular brush stroke motion. In certain embodiments, the sensor data may be a composite of different motions and is analyzed for two or more of a y-axis brush stroke motion, a z-axis brush stroke motion, a quasi-circular brush stroke motion, and a flicking brush stroke motion. The sensor data may be analyzed by the processor  1153  of the toothbrush  1103 , or the sensor data may be transmitted by the communication module  1159  of the toothbrush  1103  to the communication module  1173  of the data processing unit  1105  to be analyzed by the processor  1169  of the data processing unit  1105 . In certain embodiments, the sensor data may be analyzed in part by both the processor  1153  of the toothbrush  1103  and the processor  1169  of the data processing unit  1105 . 
     Once the sensor data has been analyzed to determine one or more brush stroke motions present in the motion of the toothbrush, an offset time determining step  1269  is performed. In the exemplary embodiment, this step  1269  is performed by the processor  1169  of the data processing unit  105 , although in other embodiments the offset time may be determined by the processor  1153  of the toothbrush  1103 . In this step  1269 , the offset time is determined using the determined brush stroke motions based on at least the start of the first or current portion of the brushing routine. The offset time is a reflection of the effectiveness of the user’s brushing routine during a particular portion of the brushing routine. In certain embodiments, the offset time may be a reflection of the effectiveness of the user’s brushing routine during two or more portions of the brushing routine, or even during the entire brushing routine. Specifically, if a portion of the brushing routine is determined to be less effective than an established standard, then the offset time is a positive number that may be used to increase the overall time length of the brushing routine. Generally, since the established standard calls for entirely circular brush strokes during a brushing routine, the offset time determined exclusively in terms of brush stroke motion will only be a positive number. However, as is discussed below, the offset time may be a negative number when brushing aggressiveness is taken into consideration. 
     The offset time may be determined by calculation, based on the percentages of different types of brush stroke motions that make up the determined brush stroke motion. Alternatively, the offset time may be determined using a lookup table, which may be a multi-dimensional matrix, each dimension representing one of the types of brush stroke motions, and each dimension divided into a plurality of values or value ranges. For example, in an embodiment in which the sensor data is analyzed for four different types of brush stroke motion, the lookup table is a four dimensional matrix. In such an embodiment, the matrix is based on calculations performed in advance, and comparison of the types of determined brush stroke motion with the matrix may yield the offset time faster than real-time calculations. 
     Following the offset time determining step  1269  is a target brushing time calculation step  1271 . In this step  1271 , the target brushing time or remaining brushing time for the brushing routine is calculated. In the exemplary embodiment, this step  1271  is also performed by the processor  1169  of the data processing unit  1105 , although in other embodiments the offset time may be determined by the processor  1153  of the toothbrush  103 . During the initial part of the brushing routine, the processor  1169  calculates the target brushing time by retrieving an optimum time which is stored in the memory  1171  and adding the determined offset time to the optimum time. For purposes of the process shown in this flowchart  1261 , the optimum time represents the established standard for brushing effectiveness. As should be apparent, the offset time may increase the target brushing time in excess of the optimum time when the offset time is determined exclusively in terms of brush stroke motion. Also, when the brush stroke motion is determined to be primarily a quasi-circular brush stroke motion, then the determined offset time is zero and the target brushing time may then be the same as the optimum time. 
     Following the initial part of the brushing routine, the processor  1169  (or alternatively, the processor  1153 ) calculates the target brushing time again in the same manner, by re-determining the offset time, and then adjusting the target brushing time accordingly. This adjustment may be accounted for by determining the ratio of the brushing time remaining to the most recently calculated target brushing time, and then applying that same ratio to a newly calculated target brushing time, based on adding the re-determined offset time to the optimum time, to determine a new value for the brushing time remaining. 
     After the target brushing time calculation step  1271  is a displaying step  1273 . During this step  1273 , the processor  1169  controls the display  1175  to indicate to the user the target brushing time and/or the brushing time remaining. While displaying the target brushing time and/or brushing time remaining, a step  1275  is performed in which the processor  1169  determines if the target brushing time has expired. When the target brushing time has expired, the processor  1169  proceeds to an indication step  1277 , in which the processor  1169  controls the display  1175  to inform the user that the brushing routine is at an end. When the target brushing time has not expired, the process returns to the sensor data generating step  1265  to continue determining the effectiveness of the user’s brushing routine. 
     In certain embodiments, the displaying step  1273  may be replaced with a more generalized feedback step, in which one of the processor  1153  of the toothbrush  1103  or the processor  1169  of the data processing unit  1105  provides feedback to the user when the target brushing time and/or the brushing time remaining has expired. Such feedback may be provided to the user, for example, as audio feedback through a speaker or visual feedback by one or more LED indicators. 
     As should be apparent from the above description of  FIG.  21   , in certain embodiments, the sensor data analysis and feedback of the target brushing time to the user may be entirely performed by the processor  1153  of the toothbrush  1103 . In certain other embodiments, the processes for the sensor data analysis and feedback may be performed partially by the processor  1153  of the toothbrush  1103  and partially by the processor  1169  of the data processing unit  1105 . In still other embodiments, the processes for the sensor data analysis and feedback may be entirely performed by the processor  1169  of the data processing unit  1105 . 
     In certain embodiments, the user may use the toothbrush  1103  without being within communication range of the data processing unit  1105  so that there is no active communication link between the toothbrush  1103  and the data processing unit  1105 . In such embodiments, the toothbrush  1103  may perform the brush stroke determining step  1267  and store a brushing profile, of the type shown in  FIG.  20   , in the memory  1157 . The next time the toothbrush  1103  is within communication range of the data processing unit  1105  and a communication link is established, the processor  1153  of the toothbrush  1103  may transmit any brushing profiles stored in memory to the data processing unit  1105 . 
     In certain embodiments, the processor  1153  of the toothbrush  1103  and/or the processor  1169  of the data processing unit  1105  may be programmed to calculate a performance metric using the determined brush stroke motion. Such a performance metric may express the brushing profile for each portion of the brushing routine, or even for the entire brushing routine, as a number. In embodiments in which the processor  1153  of the toothbrush  1103  performs the brush stroke determining step  1267 , the amount of resulting data stored in the memory may be significantly reduced for purposes of storage and later transmission to the data processing unit  105 . In still other embodiments, the processor  1169  of the data processing unit  1105  may be configured to transmit to the server  1107  any performance metrics calculated for a brushing routine. This includes performance metrics calculated by the processor  1153  of the toothbrush  103  and those calculated by the processor  1169  of the data processing unit  1105 . Calculation of performance metrics may reduce the amount of data stored in the memory  1171  of the data processing unit  1105  and/or transmitted to the server  1107  for storage. 
     In certain embodiments, brushing profiles and/or performance metrics which are stored in the memory  1171  of the data processing unit  1105  or on the server  1107  may be used during future brushing routines to aid in determining the offset time for a brushing routine. In particular, brushing profiles and/or performance metrics may be used to determine the target brushing time for a brushing routine prior to any sensor data being generated in step  1265 . In such embodiments, the calculating brushing time step  1271  is performed to adjust the target brushing time determined from the brushing profiles and/or performance metrics. Also, in embodiments in which brushing profiles and/or performance metrics are stored, the brushing profiles and/or performance metrics may be analyzed by machine learning processes, and the machine learning may be used to enhance future brushing routines. Such machine learning may be performed by any one or more processors of the oral care system  101 , and/or it may also be performed by an associated server  1107 . 
       FIG.  22    illustrates the dentiture  1301  of a user and the sixteen different sections thereof which may be brushed by different portions of the brushing routine. In certain embodiments, a one-to-one correspondence exists between each dentiture section and each portion of the brushing routine. By having such a one-to-one correspondence, in embodiments in which performance metrics are calculated, the efficiency of a user’s brushing routine for the entire dentiture may be more efficiently stored in memory for later use or reference. In certain other embodiments, any one portion of the brushing routine may correspond to multiple dentiture sections. In still other embodiments, the entire brushing routine has a single portion corresponding to all sections of the dentiture. The sections of the dentiture shown in  FIG.  22    are: upper mesial buccal section  1303 ; upper mesial lingual section  1305 ; lower mesial buccal section  1307 ; lower mesial lingual section  1309 ; upper right buccal section  1311 ; upper right lingual section  1313 ; upper right occlusal section  1315 ; upper left buccal section  1317 ; upper left lingual section  1319 ; upper left occlusal section  1321 ; lower right buccal section  1323 ; lower right lingual section  1325 ; lower right occlusal section  1327 ; lower left buccal section  1329 ; lower left lingual section  1331 ; and lower left occlusal section  1333 . 
     Another physical property which may be monitored during a brushing routine is brushing intensity, which is a measure of brushing aggressiveness during a brushing routine. Brushing aggressiveness during a brushing routine is characterized by over-brushing and/or under-brushing. Similar to how the target brushing time based on brush stroke motion is determined during a brushing routine, the target brushing time of a brushing routine based on brushing aggressiveness may also be determined. In certain embodiments, brushing aggressiveness may be used on its own to determine the target brushing time. In certain other embodiments, brushing aggressiveness may be combined with brush stroke motion to determine the target brushing time.  FIG.  23 A  illustrates a graph  1351  which shows a plot of two z-axis acceleration signals  1353 ,  1355  taken from two different brushing routines. These two acceleration signals  1353 ,  1255 , show the difference in the stroke rates used for the respective brushing routines. The stroke rate is the frequency of linear motion along the z-axis of the oral care device. The first acceleration signal  1353  is illustrative of over-brushing, while the second acceleration signal  1355  is illustrative of under-brushing. In the process described below, compensation for any over- or under-brushing may be achieved by adding a negative or positive offset time, respectively, to an optimum brushing time. As can be seen in the graph  1351 , the first acceleration signal  1353  exhibits a larger amplitude as compared to the second acceleration signal  1355 . The larger amplitude of the first acceleration signal  1353  indicate that the user is moving the head  1115  of the toothbrush  1103  in quick motions along the z-axis. In comparison, the smaller amplitude of the second acceleration signal  1355  indicate that the user is moving the head  1115  of the toothbrush  1103  in slower motions along the z-axis. 
       FIG.  23 B  illustrates the stroke intensity in a graph  1361  which shows power spectral density versus stroke rate derived from two z-axis acceleration signals  1363 ,  1365 . This graph  1361  shows the number of discrete frequencies that are present in the each of the acceleration signals  1363 ,  1365 . The first acceleration signal  1363  is illustrative of over-brushing, while the second acceleration signal  1365  is illustrative of under-brushing. As can be seen, the first acceleration signal  1363  includes a dominant peak at a higher frequency as compared to the second acceleration signal  1365 . The higher frequency of the dominant peak in the first acceleration signal  1363  is another indication that the user is moving the head  1115  of the toothbrush  1103  at a faster rate along the z-axis. In comparison, the lower frequency of the dominant peak of the second acceleration signal  1355  indicate that the user is moving the head  1115  of the toothbrush  1103  at a slower rate along the z-axis. 
     Another indication of over- or under-brushing may be obtained by a force sensor placed in the toothbrush  1103 . The force sensor may be positioned within the handle  1111  of the toothbrush  1103  so that as teeth are brushed, the force sensor generates sensor data which is indicative of the amount of pressure placed on the teeth by the bristles  1149 . 
     A flowchart  1371  showing an exemplary process for at least a portion of brushing routine is shown in  FIG.  24   . The process of this flowchart  1371  serves to determine and/or adjust a target brushing time of a brushing routine based upon a determined brushing aggressiveness during the brushing routine. As should be appreciated, the target brushing time may be determined by processes different or varying from this exemplary process, such that the invention is not to be limited to the exemplary process. An initiation step  1373  starts off the brushing routine. This initiation step  1373  may be achieved by the user pressing a button on one of the toothbrush  1103  or on the data processing unit  1105 . Using the toothbrush  1103 , in certain embodiments, the initiation step  1373  may be achieved by the user actuating the electrical switch  1143 . On the data processing unit  1105 , in certain embodiments, the initiation step  1373  may be achieved by first pressing the electrical switch  1143  on the toothbrush  1103  to power the electrical circuitry  1151  of the toothbrush  1103  and then pressing a button on the data processing unit  1105 , or if the data processing unit  1105  includes a touch sensitive display, touching a virtual button shown on the display  1175 . 
     As part of the initiation step  1373 , the user begins the brushing routine. In certain embodiments, the data processing unit  1105  may direct the user to follow a predetermined sequence for the brushing routine, starting the brushing routine by brushing a predetermined section of the dentiture of the user and then continuing to other sections of the dentiture according to the predetermined sequence. In other embodiments, in which the toothbrush  1103  has appropriate tracking sensors and the data processing unit  1105  is able to determine which sections of the dentiture are being brushed, regardless of sequence, the data processing unit  1105  may direct the user to start the brushing routine by first brushing a predetermined section of the dentiture and then tracking which sections are brushed and for how long each is brushed during the brushing routine. In still other embodiments, the user may provide input to the data processing unit to indicate the section of the dentiture that will be brushed during the first portion of the brushing routine and during each subsequent portion of the brushing routine. 
     Following the initiation step  1373  is a sensor data generating step  1375  which is performed by the electronic circuitry  1151  of the toothbrush  1103 . During this step  1375 , the sensors  1155  included in the toothbrush sense the physical properties each is configured to monitor and generate signals accordingly as the brushing routine begins and continues. For determining brushing aggressiveness, the sensors may include at least one of an accelerometer and a force sensor. Next is the brushing aggressiveness determination step  1377 . In this step  1377 , the sensor data is analyzed to determine the brushing aggressiveness for the first and/or current portion of the brushing routine. In other words, the sensor data may be analyzed in real time. As indicated above, brushing aggressiveness may be determined by analyzing one or more of an acceleration signal, a power spectral density of an acceleration signal, and a force signal. The sensor data may be analyzed by the processor  1153  of the toothbrush  1103 , or the sensor data may be transmitted by the communication module  1159  of the toothbrush  1103  to the communication module  1173  of the data processing unit  1105  to be analyzed by the processor  1169  of the data processing unit  1105 . In certain embodiments, the sensor data may be analyzed in part by both the processor  1153  of the toothbrush  1103  and the processor  1169  of the data processing unit  1105 . 
     Once the sensor data has been analyzed to determine the brushing aggressiveness, an offset time determining step  1379  is performed. In the exemplary embodiment, this step  1379  is performed by the processor  1169  of the data processing unit  1105 . In this step  1379 , the offset time is determined using the determined brushing aggressiveness based on at least the start of the first portion of the brushing routine. The offset time is a reflection of the over- or under-brushing of the user’s brushing routine during a particular portion of the brushing routine. In certain embodiments, the offset time may be a reflection of the over- or under-brushing of the user’s brushing routine during two or more portions of the brushing routine, or even during the entire brushing routine. Specifically, if a portion of the brushing routine is determined to include under-brushing as compared to an established standard, then the offset time may be a positive number that may be used to increase the time of the brushing routine. Alternatively, if a portion of the brushing routine is determined to include over-brushing as compared to the established standard, then the offset time is a negative number that may be used to decrease the time of the brushing routine. 
     The offset time may be determined by calculation, based on the amount of over- or under-brushing, or alternatively, the offset time may be determined through use of a lookup table. In embodiments which use a lookup table, all potential offset times included in the lookup table are calculated in advance. 
     Following the offset time determining step  1379  is a target brushing time calculation step  1381 . In this step  1381 , the target brushing time or remaining brushing time for the brushing routine is calculated. In the exemplary embodiment, this step  1381  is also performed by the processor  1169  of the data processing unit  105 . During the initial part of the brushing routine, the processor  1169  calculates the target brushing time by retrieving an optimum time which is stored in the memory  1171  and adding the determined offset time to the optimum time. For purposes of the process shown in this flowchart  1371 , the optimum time represents the established standard based on a generally neutral brushing aggressiveness. 
     Following the initial part of the brushing routine, the processor  1169  calculates the target brushing time in the same manner, by re-determining the offset time, and then adjusting the target brushing time accordingly. This adjustment may be accounted for by determining the ratio of the brushing time remaining to the most recently calculated target brushing time, and then applying that same ratio to a newly calculated target brushing time, based on adding the re-determined offset time to the optimum time, to determine a new value for the brushing time remaining. 
     After the target brushing time calculation step  1381  is a displaying step  1383 . During this step  1383 , the processor  1169  controls the display  1175  to indicate to the user the target brushing time and/or the brushing time remaining. During the displaying step  1383  is a step  1385  in which the processor  1169  determines if the target brushing time has expired. When the target brushing time has expired, the processor  1169  proceeds to an indication step  1387 , in which the processor  1169  controls the display  1175  to inform the user that the brushing routine is at an end. When the target brushing time has not expired, the process returns to the sensor data generating step  1375  to continue determining the brushing aggressiveness of the user’s brushing routine. 
     In certain embodiments, the displaying step  1383  may be replaced with a more generalized feedback step, in which one of the processor  1153  of the toothbrush  1103  or the processor  1169  of the data processing unit  1105  provides feedback to the user when the target brushing time and/or the brushing time remaining has expired. Such feedback may be provided to the user, for example, as audio feedback through a speaker or visual feedback by one or more LED indicators. 
     As should be apparent from the above description of  FIG.  24   , in certain embodiments, the entirety of the sensor data analysis and feedback of the target brushing time to the user may be entirely performed by the processor  1153  of the toothbrush  1103 . In certain other embodiments, the processes for the sensor data analysis and feedback may be performed partially by the processor  1153  of the toothbrush  1103  and partially by the processor  1169  of the data processing unit  1105 . In still other embodiments, the processes for the sensor data analysis and feedback may be entirely performed by the processor  1169  of the data processing unit  1105 . 
     In certain embodiments, the processor  1153  of the toothbrush  1103  and/or the processor  1169  of the data processing unit  1105  may be programmed to calculate a performance metric using the determined brushing aggressiveness. Such a performance metric may express the brushing aggressiveness for each portion of the brushing routine, or even for the entire brushing routine, as a number. In embodiments in which the processor  1153  of the toothbrush  1103  performs the brushing aggressiveness determining step  1377 , the amount of resulting data stored in the memory may be significantly reduced for purposes of storage and later transmission to the data processing unit  1105 . In still other embodiments, the processor  1169  of the data processing unit  105  may be configured to transmit to the server  1107  any performance metrics calculated for a brushing routine. This includes performance metrics calculated by the processor  1153  of the toothbrush  1103  and those calculated by the processor  1169  of the data processing unit  1105 . Calculation of performance metrics may reduce the amount of data stored in the memory  1171  of the data processing unit  1105  and/or transmitted to the server  1107  for storage. 
     In certain embodiments, brushing profiles and/or performance metrics which are stored in the memory  1171  of the data processing unit  1105  or on the server  1107  may be used during future brushing routines to aid in determining the offset time for a brushing routine. In particular, brushing profiles and/or performance metrics may be used to determine the target brushing time for a brushing routine prior to any sensor data being generated in step  1375 . In such embodiments, the calculating the target brushing time step  1381  is performed to adjust the target brushing time determined from the brushing profiles and/or performance metrics. Also, in embodiments in which brushing profiles and/or performance metrics are stored, the brushing profiles and/or performance metrics may be analyzed by machine learning processes, and the machine learning may be used to enhance future brushing routines. Such machine learning may be performed by any one or more processors of the oral care system  1101 , and/or it may also be performed by an associated server  1107 . 
       FIG.  25 A  illustrates an oral care system  2101  in accordance with an embodiment of the present invention. The oral care system  2101  includes a toothbrush  2103  and a data processing unit  2105 . The data processing unit  2105  may communicate with a server  2107  for purposes of storing larger amounts of data or to provide server-side processing functionality. The presence of the server  2107  and communication between the data processing unit  2105  and the server  2107 , however, are not limiting of the present invention, unless specifically set forth in a claim. 
     The toothbrush  2103  may be of any type that includes teeth cleaning elements suitable for cleaning teeth, and therefore is not limited to the toothbrush  2103  illustrated as part of the exemplary embodiment. The toothbrush  2103  shown in  FIG.  25 A  generally includes a handle  2111 , a neck  2113 , and a head  2115 . The neck  2113  extends between the handle  2111  and the head  2115  and connects the head  2115  to the handle  2111 . The handle  2111  provides the user with a mechanism by which the toothbrush  2103  can be readily gripped and manipulated during a brushing session. The handle  2111  may be formed of many different shapes, sizes and materials and may be formed by a variety of manufacturing methods that are well-known to those skilled in the art. The handle  2111  extends from a proximal end  2117  to a distal end  2119  to form an elongated gripping portion  2123  therebetween. The handle  2111  transitions into the neck  2113  at the distal end  2119 . While the neck  2113  generally has a smaller transverse cross-sectional area than the handle  2111 , the invention is not so limited. Broadly speaking, the neck  2113  forms a transition region between the handle  2111  and the head  2115 , with the head  2115  extending from a proximal end  2125  at the end of the neck  2113  opposite the handle  2111  to a distal end  2127 . While the head  2115  is normally widened relative to the neck  2113 , in some embodiments the head  2115  can simply be a continuous extension or narrowing of the neck  2113  and/or handle  2111 . 
     The handle  2111 , the neck  2113 , and the head  2115  may be formed as separate components which are operably connected at a later stage of the manufacturing process by any suitable technique known in the art, including without limitation thermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve, threaded engagement, adhesion, or fasteners. However, in other embodiments, the handle  2111 , the neck  2113 , and the head  2115  of the toothbrush  2103  may be formed as a single unitary structure using a molding, milling, machining, or other suitable process. In certain embodiments, the neck  2113  may be made from a material which is more flexible than the handle  2111  or the head  2115 , and in such embodiments, the flexibility of the neck  2113  provides the head  2115  with mobility with respect to the handle  2111 . Whether the handle  2111 , the neck  2113 , and the head  2115  are of a unitary or multi-piece construction (including connection techniques) is not limiting of the present invention, unless specifically set forth in a claim. In some embodiments of the invention, the head  2115  can have a first portion that is flexibly attached to a second portion of the head  2115 . During brushing, the first portion can move with respect to the second portion to enhance the brush head’s ability to reach certain portions of the dentiture. In some embodiments of the invention, the head  2115  may be detachable (and replaceable) from the handle  2111  and/or from the neck  2113  using techniques known in the art. 
     The head  2115  generally includes a front surface  2143 , a rear surface  2145  and peripheral side surfaces  2147  that extend between the front and rear surfaces  2143 ,  2145 . The front surface  2143  and the rear surface  2145  of the head  2115  can take on a wide variety of shapes and contours, none of which are limiting of the present invention. For example, the front and rear surfaces  2143 ,  2145  can be planar, contoured or combinations thereof. 
     The front surface  2143  of the head  2115  includes at least one teeth cleaning element, shown in the exemplary embodiment as a plurality of bristles  2149 , extending therefrom for cleaning teeth surfaces. As used herein, the term “teeth cleaning element” is used in a generic sense to refer to any structure that can be used to clean or polish the teeth through relative surface contact. In certain embodiments, the head  2115  may include a single teeth cleaning element, and in other embodiments, the head  2115  may include two or more teeth cleaning elements. Common examples of the at least one teeth cleaning element include, without limitation, bristle tufts, filament bristles, fiber bristles, nylon bristles, spiral bristles, rubber bristles, elastomeric protrusions, flexible polymer protrusions, combinations thereof and/or structures containing such materials or combinations. Suitable elastomeric materials include any biocompatible resilient material suitable for uses in an oral hygiene apparatus. To provide optimum comfort as well as cleaning benefits, the at least one teeth cleaning element may be an elastomeric material having a hardness property in the range of A8 to A25 Shore hardness. Other materials within and outside the noted hardness range may also be used. 
     The bristles  2149  of the toothbrush  2111  can be connected to the head  2115  in any manner known in the art. For example, staples/anchors, in-mold tufting (IMT) or anchor free tufting (AFT) could be used to mount the bristles  2149  of the exemplary embodiment. In AFT, a plate or membrane is secured to the brush head such as by ultrasonic welding. The bristles extend through the plate or membrane. The free ends of the bristles on one side of the plate or membrane perform the cleaning function. The ends of the bristles on the other side of the plate or membrane are melted together by heat to be anchored in place. Alternatively, the bristles may be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles are mounted within or below the tuft blocks. 
     Referring to both  FIGS.  25 A and  25 B , the data processing unit  2105  includes a housing  2163  and electronic circuitry  2165 , with the housing  2163  enclosing and/or supporting the various components of the electronic circuitry  2165 . The electronic circuitry  2165  includes a power source, shown as a battery  2167  in the exemplary embodiment. Of course, the invention is not so limited, and other types of power sources may be used. The electronic circuitry  2165  of the data processing unit  2105  also includes a processor  2169  communicably coupled to a memory  2171 , a communication module  2173 , and a user interface  2175 . 
     In certain embodiments, the electronic circuitry  2165  may include other components, such as a speaker to provide audible feedback to the user, one or more buttons to receive input from the user, and one or more ports for making a wired connection between the electronic circuitry  2165  and other circuitry external to the data processing unit  2105 . In certain other embodiments, the data processing unit  2105  may be a smartphone, a tablet computer, a laptop computer, and the like, although the invention is not so limiting. In the exemplified embodiment, the electronic circuitry  2165  is located within housing  2163  of the data processing unit  2105 , this housing  2163  being separate and distinct from the housing  2103 A of the toothbrush  2103  In other embodiments, such as that discussed below with respect to  FIG.  28   , the electronic circuitry  2165  or certain components thereof may be located within the housing  2103 A of the toothbrush  2103 . 
     The memory  2171  may be any appropriate type of memory or storage which enables the processor  2169  to perform the desired programming, such as volatile and/or non-volatile random access memory. The particular type of storage used for the memory  2171  is not to be limiting of the invention. 
     In the exemplified embodiment, the user interface  2175  is a touch-sensitive display which accepts input from the user directly on the display surface. The display may be any type of light emitting display, and as shown in the exemplary embodiment, the display may be an LED panel. In certain other embodiments, the display may be an LCD panel, an OLED panel, or any other type of display which is electronically controllable by the programmable processor  2169  to provide visual feedback to the user. As will be discussed below, the user interface is not limited to the exemplary embodiment, but can comprise any device or method by which a user interacts with the data processing unit or a programmable processor. For example, in other embodiments the user interface can utilize a non-touch-sensitive graphical user interface, buttons, a dial, a keyboard, and/or a mouse. 
     The communication module  2173  may include an antenna  2181  to enable wireless transmission of communication signals. The communication module  2173  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, Bluetooth@, and the like, or it may communicate using any type of proprietary wireless transmission protocol. The mode of communication for which the communication module  2173  is configured is not limiting of the invention unless specifically set forth in a claim. In certain embodiments, the communication module  2173  may include a port to enable communications using wires and wired protocols, such as USB and the like. 
     The communication module  2173  of the data processing unit  2105  may be configured and/or programmed to communicate with the server  2107 . The communication module  2173  may communicate with the server  2107  over any combination of public and/or private network, and the communications may be wired, wireless, or a combination of the two. In certain embodiments, the communication module  2173  may communicate with the server  2107  over the Internet using one or more types of communication protocols. In certain embodiments, the server  2107  may be programmed with one or more application programming interfaces (APIs) which provides server-side functionality to the data processing unit  2105 . 
       FIG.  26    is a flowchart showing a process  2200  for determining a brushing routine and a brushing evaluation from a brushing goal according to an embodiment of the invention. The exemplified process  2200  may be implemented as programming for the programmable processor  2169  of the data processing unit  2105 . For convenience, as part of the description below, reference will also be made to the hardware components of the data processing unit  2105  discussed above in  FIG.  25 B . While in the exemplified embodiment the processor  2169  and other electronic circuitry  2165  form part of the data processing unit, the disclosure is not so limited. For example, in other embodiments, a processor forming part of the toothbrush can carry out the steps carried out by processor  2169  in the embodiments discussed herein. 
     In a first operation, the user interface  2175  receives a brushing goal (operation  2202 ). In the exemplified embodiment, the brushing goal is received by the user through a touch-sensitive display, though the brushing goal can be received through any user interface. The brushing goal can be any objective for a brushing session. In one embodiment, the brushing goal can be chosen from two options: a standard deep cleaning and a quick refreshing cleaning. In other embodiments, the brushing goal can be chosen from alternative options, such as a mild, moderate, or heavy cleaning. In yet other options, the brushing goal can be a cleaning that is focused on removing particles from the front teeth, a cleaning that is focused on removing food from the molars, or a cleaning for a set period of time. 
     In a further operation, brushing goal data can be generated, transmitted, and/or received, the brushing goal data being indicative of the brushing goal received by the user interface (operation  2204 ). For purposes of the present disclosure, the term “brushing goal data” is any type of information indicative of a brushing goal of a user, including information extracted or derived from other information or data indicative of a brushing goal, regardless of the form of the extracted information, and combinations thereof. The brushing goal data may be in the form of mathematical data, analog data, and/or digital data. In the exemplified embodiment, the user interface  2175  receives the brushing goal, generates brushing goal data based on the brushing goal, and transmits the brushing goal data to the programmable processor  2169 . But the invention is not so limited. For example, in other embodiments, the programmable processor can work with the user interface to receive and process brushing goal data. 
     In a further operation, a suggested brushing routine is determined based at least in part on the brushing goal data (operation  2206 ). The suggested brushing routine can be any one or more steps or instructions for brushing teeth. The determination of the suggested brushing routine may be achieved in any number of ways. In certain embodiments, the suggested brushing routine may be determined by presenting the user with a list of potential brushing routines that accord with the selected brushing goal, and having the user select the suggested brushing routine from among the list of potential brushing routines. In certain embodiments, the suggested brushing routine may be determined by adjusting a standardized brushing routine based on the brushing goal data, or by adjusting a time based on the brushing goal data, as described below. In certain embodiments, the suggested brushing routine may be determined by selecting a predetermined brushing routine based on the brushing goal data and then adjusting the predetermined brushing routine based on a user brushing history. In such embodiments, the user brushing history may be based upon brushing session data collected from previous brushing sessions of the user. Such brushing session data may be based upon brush stroke, brushing aggressiveness, or upon any other measure of brushing effectiveness. In addition, such brushing session data may be saved in the memory  2171  of the data processing unit  2105  or in a memory of the server  2107 . In still other embodiments, one or more of the aforementioned processes for determining the suggested brushing routine may be used in combination. 
     In one embodiment, the suggested brushing routine is determined by adjusting an optimum brushing time based on the brushing goal data to determine the brushing time for the suggested brushing routine. In this embodiment, the optimum brushing time is predetermined from a standardized brushing routine. The standardized brushing routine may be an industry standard brushing routine in which the optimum brushing time is 2 minutes. This process can begin with the brushing goal data being received by the data processing unit  2105 . Next, the data processing unit  2105  determines an offset time based on the brushing goal data. For example, if the goal is a quick refresh of the oral cavity, then the offset time may be a negative number. Following the offset time determination, the target brushing time for the brushing routine is calculated. As part of this step, the programmable processor  2169  of the data processing unit  2105  calculates the target brushing time by retrieving an optimum time which is stored in the memory  2171  and adding the determined offset time to the optimum time. The determined target brushing time can then be displayed, and the user can be instructed to begin the suggested brushing routine. In certain embodiments, the processor  2169  of the data processing unit  2105  may provide other specific instructions for the brushing routine, such as the order for brushing different sections of the user’s dentiture, the length of time to brush each section, which section to start with, and the like. When the brushing time has expired, the programmable processor  2169  of the data processing unit  2105  can instruct the user that the brushing routine is at an end. 
     In the exemplified embodiment, after determining the suggested brushing routine, there is a determination of a brushing evaluation based on the brushing goal data (step  2208 ). As will be discussed in further detail below, the oral care system  2101  can be configured to perform a brushing evaluation of a brushing session of a user. The brushing evaluation can be any assessment of the effectiveness of one or more brushing sessions. For example, the toothbrush  2103  can include sensors, and data derived from the sensors can be used to determine the motion and/or location of the toothbrush. From this determination, the system  2101  can determine how well the user brushed his or her teeth. In the exemplified embodiment, the evaluation is based in part on the brushing goal data. Thus, for example, while a brushing evaluation would typically provide a negative evaluation when the brushing session was only one minute, the brushing evaluation according to the invention need not be negative if the user indicated that the purpose of the given brushing session was only a quick refresh of the oral cavity. Accordingly, the user is not penalized in his brushing evaluation for carrying out a supplemental brushing session for refreshing his oral cavity. In one embodiment, the determination of the brushing evaluation is based on both brushing goal data and brushing data from a brushing session, the brushing data being derived from a sensor forming part of the toothbrush. Further, the brushing evaluation can be based on a comparison of the brushing data from the brushing session and the suggested brushing routine. 
     The brushing goal data can impact an evaluation of an individual brushing session, and can also impact an evaluation of a plurality of brushing sessions. Thus, while one-minute of brushing may be adequate for a modest brushing goal, carrying out only two one-minute brushing sessions per day will not be adequate, and a cumulative evaluation can reflect this. The cumulative evaluation will not penalize a user for meeting a modest brushing goal for a session, but will also ensure that general brushing goals are being met. Such general brushing goals can be based on established ideal brushing objectives, or can be individualized based on factors particular to the user. 
     In the foregoing method  2200 , the brushing goal data is used to both determine a suggested brushing routine and determine a brushing evaluation. It is noted, however, that in other embodiments the brushing goal data can be used to determine a suggested brushing routine but not to determine a brushing evaluation, or to determine a brushing evaluation but not to determine a suggested brushing routine. 
       FIG.  27    illustrates a data processing unit  2105  having a user interface  2175  according to one embodiment. Here, the user may input the brushing goal data through the user interface  2175 . In such embodiments, the data processing unit  2105  may present to the user using the user interface one or more questions  2302  concerning at least one brushing goal of the user, and then receive a selected answer  2304  to the one or more questions. The questions and answers shown are merely exemplary in nature, and any of the brushing goals discussed herein (as well as others) can be the subject of a question or answer on a user interface for the purposes of receiving brushing goal data. In other embodiments, a user can type a goal and be provided with options that corresponded with the typed goal. In other embodiments, a series of questions or topics can be provided to the user by the user interface. For example, in addition to the type of brushing session, the user can be prompted to indicate the intended brushing time or an area of the oral cavity upon which the user would like to focus. 
       FIG.  28    illustrates a toothbrush  2103 B comprising a user interface  2175 B according to another embodiment of the invention. In this embodiment, the toothbrush  2103 B comprises the user interface  2175 B and the programmable processor (not shown). The user interface  2175 B comprises buttons  2303 B for selecting a brushing goal option. Brushing goal data can be generated based on the button  2303 B pressed, and the brushing goal data can be utilized as discussed herein. The exemplified user interface  2175 B further comprises a display  2175 B. The display can provide information similar to the information displayed on the touch-sensitive display  2175 . For example, the display  2175  can provide information regarding a suggested brushing routine, or brushing evaluation information. In other embodiments, other buttons indicative of other goals can be used. For example, a button can indicate increased or decreased brushing time, which can then be shown on the display  2175 B. In other embodiments, the display  2175  can be omitted. In this case, the user can indicate his brushing goal using the buttons (or other user interface) on the toothbrush, but the determined routine or evaluation can appear elsewhere, such as on a data processing unit. Further, the toothbrush  2103 B can be any type of toothbrush, including a manual toothbrush or an electric toothbrush having an electrically-powered vibratory element. 
       FIG.  29    illustrates a data processing unit  2105  having a user interface  2175  that provides brushing instructions  2510  for a brushing routine according to one embodiment, the instructions  2510  being based in part on the brushing goal received. In this embodiment, the brushing instructions  2510  comprise real-time directions for a user to follow during a brushing session. The instructions  2510  comprise an indication  2514  of a region of the dentiture to brush, an indication  2512  of a brushing motion, and an indication  2516  of a time remaining for brushing the specified region. In this embodiment, the user interface  2175  also provides an indication  2518  of the total brushing time remaining in the suggested brushing routine. In this embodiment, different screens may show different instructions as the user progresses through the different stages of the brushing routine, thus coaching the user on which regions to brush, which brushing motions to use, and for how long. In other embodiments, certain indications or instructions can be omitted. Also, other indications or instructions can be added, such as an indication of whether to apply greater or lesser pressure or brushing intensity. The instructions (such as motion, region, and time) can be based at least in part on the brushing goal of the user. Thus, for example, if the user desired only a quick refresh of the oral cavity, the routine could reflect this goal by decreasing the time to be less than a typical brushing session, or by changing the brushing motions provided or the brushing regions indicated to those more likely to promote fresh breath. Further, if the user wished to dedicate more time to removing food from the molars, the instructions could reflect this goal by extending the time dedicated to the molars from the time typically dedicated to the molars. 
     The suggested brushing routine can be determined by adjusting a preexisting brushing routine, the adjustment based at least in part on the brushing goal data. In other embodiments, the suggested brushing routine need not rely on a preexisting brushing routine. 
       FIG.  30    illustrates a data processing unit  2105  having a user interface  2175  that provides an evaluation  2520  of a brushing session of a user according to an embodiment of the invention. In this embodiment, the evaluation  2520  comprises a visualization  2521  of the user’s dentiture. The dentiture can be divided into different regions, each of which the user is expected to brush during the brushing session. Brushing session data may be collected and processed according to the different regions of the dentiture. The collection of such brushing session data is described in more detail below with respect to  FIGS.  32 - 34   . 
     In the exemplified embodiment, the visualization  2521  includes an indication  2522  of a region of the dentiture not properly brushed. The evaluation  2520  further comprises a recommendation  2526  that provides the user advice on how to improve his or her brushing. The evaluation  2520  also includes a performance metric  2524  that indicates how well the user performed in brushing his or her teeth during the brushing session. In other embodiments, other metrics or visualizations can be used to indicate brushing performance, such as a percentage, or a number of stars (for example, three stars out of five). Further, as discussed above, in other embodiments, the evaluation can be a cumulative evaluation based on a plurality of brushing sessions and brushing goal data from those brushing sessions. 
       FIG.  31    illustrates an electronic toothbrush  2281  according to an embodiment of the invention. The electric toothbrush  2281  includes a handle  2283  and a refill head  2285 . In certain embodiments, the handle  2283  and the refill head  2285  are removably coupled to each other. In certain embodiments of electric toothbrushes, the control circuit  2165  of the data processing unit  2105  may reside at least partially within the handle  2283 . Alternatively, the handle  2283  may include a separate toothbrush control circuit which controls the electric toothbrush and communicates with the data processing unit  2105 . 
     In this embodiment, the refill head  2285  includes a bristle field  2287  which includes at least one elastomeric element  2289  and a tongue cleaner  2291  on the back side  2292  of the refill head  2285 . Also in this embodiment, shown schematically, the handle includes a motor  2294  operably coupled to a shaft  2295 , with an eccentric mass  2297  positioned at the distal end of the shaft  2295 . In combination, the motor  2294 , the shaft  2295 , and the eccentric mass  2297  form an electrically-powered vibratory element. 
       FIG.  32    illustrates a partial sectional view of a toothbrush  2351  having electronic circuitry for collecting brushing session data according to an embodiment of the invention. The handle  2343  of the toothbrush  2341  forms a housing for containing electronic circuitry  2351  for collecting brushing session data. The handle  2343  is a hollow structure in which a cavity  2345  is formed. The electronic circuitry  2351 , which includes a power source  2352 , is located within the cavity. The electronic circuitry  2351  may be used to collect and analyze brushing session data from which an evaluation of the brushing session may be made. In certain embodiments, the evaluation of the brushing session may be based at least in part upon the brushing goal data. 
       FIG.  33    is a schematic of the electronic circuity  2351  of the toothbrush  2341  of  FIG.  32   . The electronic circuitry  2351  includes a processor  2353  communicably coupled to sensors  2355 , a memory  2357 , and a communication module  2359 . The number of sensors  2355  included as part of the electronic circuitry  2351  depends upon the type of brushing session data to be detected and the functionality of each type of sensor employed. The brushing session data that is detected and collected may include position, motion, acceleration, frequency, and pressure against the surface of the teeth. Other types of brushing session data associated with a brushing session may also be detected and collected, and those listed herein are not to be limiting of the invention unless otherwise indicated in the claims. In certain embodiments, only one sensor  2355  may be included as part of the electronic circuitry  2351 , and in other embodiments, two or more sensors  2355  may be included. By way of example, the at least one sensor  2355  may be any one or more of the following: a 3-axis accelerometer, a 6-axis accelerometer, a gyroscope, a magnetometer, a pressure sensor, among other types of sensors. In general, each sensor  2355  included as part of the electronic circuitry  2351  generates at least part of the brushing session data. For purposes of the present disclosure, the term “brushing session data” is any type of information which may be extracted or derived from a sensor or sensor signal, regardless of the form of the extracted information. By way of example, brushing session data may be in the form of mathematical data (such as a formula which mathematically represents at least part of the sensor signal), analog data (such as the waveform of the sensor signal), and/or digital data (such as a representation of at least part of the sensor signal in a digital format). In certain embodiments, the processor  2353  and the memory  2357  may be omitted from the electronic circuitry  2351  of the toothbrush  2341 . In such embodiments, the sensors  2355  may communicate brushing session data directly to the communication module for transmission. 
     The memory  2357  may be any appropriate type of memory or storage which enables the processor  2353  to perform the desired programming, such as volatile and/or non-volatile random access memory, or any other type of storage. The particular type of storage used for the memory  2357  is not to be limiting of the invention. The communication module  2359  in the exemplary embodiment includes an antenna  2361  to enable wireless communication. The communication module  2359  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, BluetoothⓇ, and the like, or it may communicate using any type of proprietary wireless transmission protocol. In certain embodiments, the communication module  2359  may include a port to enable communications using wires and wired protocols, such as USB and the like. The particular mode of communication used by the communication module is not limiting of the invention unless specifically set forth in a claim. 
       FIG.  34    illustrates a toothbrush dongle  2391  for collecting brushing session data. Generally, the toothbrush  2381  includes a handle  2383  and a head  2385  to which a plurality of teeth cleaning elements  2387  are affixed. The dongle  2391  may be removably affixed to the proximal end  2389  of the handle  2383 . The dongle  2391  comprises a housing for containing electronic circuitry  2393  and an associated a power source  2395 , which may be similar to that described above in connection with  FIG.  33   . 
     The brushing session data which is detected and collected by the toothbrush embodiments shown in  FIGS.  32 - 34    may include a side-to-side linear brush stroke motion, an up and down linear brush stroke motion, a circular brush stroke motion, a flicking brush stroke motion, a brush stroke rate, and a pressure of the head of the toothbrush on the teeth, amongst others. During use, the brushing session data is generated during at least a portion of the brushing session. The brushing session data may be used to evaluate the brushing session by calculating one or more performance metrics, and the performance metric may represent brushing efficacy during one or more portions of the brushing session. The performance metric may express the efficacy of a brushing session, or even for portions of a brushing session, as a single number, and stored in the memory  2171  of the data processing unit  2105  for later use. In certain embodiments, the data processing device  2105  may transmit the calculated performance metrics to the server  2107  for storage and or additional analysis. 
     In certain embodiments, the performance metrics which are stored in the memory  2171  of the data processing unit  2105  or on the server  2107  may be used during future brushing sessions to aid in determining what brushing routine to suggest to the user. For example, performance metrics may be used in combination with the brushing goal data to help determine the target brushing time for a brushing routine. Also, in embodiments in which performance metrics are stored, the performance metrics may be analyzed by machine learning processes, and the machine learning may be used to enhance future brushing routines. 
     The disclosed embodiments provide several advantages. For example, the system can provide a brushing routine that takes into consideration the brushing goal of the user. Thus, the brushing routine provided can reflect the objective of a user for a given brushing session, rather than providing the same standard routine regardless of the situation. Further, the system can provide a brushing evaluation that takes into consideration the brushing goal of the user. Thus, an evaluation can be based on what the user intended to accomplish during the brushing session, rather than judging the brushing session based on an unadaptable, one-size-fits-all standard. 
     Turning in detail to the drawings,  FIG.  35 A  illustrates an oral care system  3101  in accordance with an embodiment of the present invention. The oral care system  3101  includes a toothbrush  3103  and a data processing unit  3105 . The data processing unit  3105  may communicate with a server  3107 , for example, for purposes of storing larger amounts of data or to provide server-side processing functionality. The presence of the server  3107  and communication between the data processing unit  3105  and the server  3107 , however, are not limiting of the present invention, unless specifically set forth in a claim. 
     The toothbrush  3103  may be of any type that includes teeth cleaning elements suitable for cleaning teeth, and therefore is not limited to the toothbrush  3103  illustrated as part of the exemplary embodiment. The toothbrush  3103  shown in  FIG.  35 A  generally includes a handle  3111 , a neck  3113 , and a head  3115 . The neck  3113  extends between the handle  3111  and the head  3115  and connects the head  3115  to the handle  3111 . The handle  3111  provides the user with a mechanism by which the toothbrush  3103  can be readily gripped and manipulated during a brushing session. The handle  3111  may be formed of many different shapes, sizes and materials and may be formed by a variety of manufacturing methods that are well-known to those skilled in the art. The handle  3111  extends from a proximal end  3117  to a distal end  3119  to form an elongated gripping portion  3123  therebetween. The handle  3111  transitions into the neck  3113  at the distal end  3119 . While the neck  3113  generally has a smaller transverse cross-sectional area than the handle  3111 , the invention is not so limited. Broadly speaking, the neck  3113  forms a transition region between the handle  3111  and the head  3115 , with the head  3115  extending from a proximal end  3125  at the end of the neck  3113  opposite the handle  3111  to a distal end  3127 . While the head  3115  is normally widened relative to the neck  3113 , in some embodiments the head  3115  can simply be a continuous extension or narrowing of the neck  3113  and/or handle  3111 . 
     The handle  3111 , the neck  3113 , and the head  3115  may be formed as separate components which are operably connected at a later stage of the manufacturing process by any suitable technique known in the art, including without limitation thermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve, threaded engagement, adhesion, or fasteners. However, in other embodiments, the handle  3111 , the neck  3113 , and the head  3115  of the toothbrush  3103  may be formed as a single unitary structure using a molding, milling, machining, or other suitable process. In certain embodiments, the neck  3113  may be made from a material which is more flexible than the handle  3111  or the head  3115 , and in such embodiments, the flexibility of the neck  3113  provides the head  3115  with mobility with respect to the handle  3111 . Whether the handle  3111 , the neck  3113 , and the head  3115  are of a unitary or multi-piece construction (including connection techniques) is not limiting of the present invention, unless specifically set forth in a claim. In some embodiments of the invention, the head  3115  can have a first portion that is flexibly attached to a second portion of the head  3115 . During brushing, the first portion can move with respect to the second portion to enhance the brush head’s ability to reach certain portions of the dentiture of the user (the dentiture being understood as the user’s set of teeth). In some embodiments of the invention, the head  3115  may be detachable (and replaceable) from the handle  3111  and/or from the neck  3113  using techniques known in the art. 
     The head  3115  generally includes a front surface  3143 , a rear surface  3145  and peripheral side surfaces  3147  that extend between the front and rear surfaces  3143 ,  3145 . The front surface  3143  and the rear surface  3145  of the head  3115  can take on a wide variety of shapes and contours, none of which are limiting of the present invention. For example, the front and rear surfaces  3143 ,  3145  can be planar, contoured or combinations thereof. 
     The front surface  3143  of the head  3115  includes at least one teeth cleaning element, shown in the exemplary embodiment as a plurality of bristles  3149 , extending therefrom for cleaning teeth surfaces. As used herein, the term “teeth cleaning element” is used in a generic sense to refer to any structure that can be used to clean or polish the teeth through relative surface contact. In certain embodiments, the head  3115  may include a single teeth cleaning element, and in other embodiments, the head  3115  may include two or more teeth cleaning elements. Common examples of the at least one teeth cleaning element include, without limitation, bristle tufts, filament bristles, fiber bristles, nylon bristles, spiral bristles, rubber bristles, elastomeric protrusions, flexible polymer protrusions, combinations thereof and/or structures containing such materials or combinations. Suitable elastomeric materials include any biocompatible resilient material suitable for uses in an oral hygiene apparatus. To provide optimum comfort as well as cleaning benefits, the at least one teeth cleaning element may be an elastomeric material having a hardness property in the range of A8 to A25 Shore hardness. Other materials within and outside the noted hardness range may also be used. 
     The bristles  3149  of the toothbrush  3111  can be connected to the head  3115  in any manner known in the art. For example, staples/anchors, in-mold tufting (IMT) or anchor free tufting (AFT) could be used to mount the bristles  3149  of the exemplary embodiment. In AFT, a plate or membrane is secured to the brush head such as by ultrasonic welding. The bristles extend through the plate or membrane. The free ends of the bristles on one side of the plate or membrane perform the cleaning function. The ends of the bristles on the other side of the plate or membrane are melted together by heat to be anchored in place. Alternatively, the bristles may be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles are mounted within or below the tuft blocks. 
     Referring to both  FIGS.  35 A and  35 B , the data processing unit  3105  includes a housing  3163  and electronic circuitry  3165 , with the housing  3163  enclosing and/or supporting the various components of the electronic circuitry  3165 . The electronic circuitry  3165  includes a power source, shown as a battery  3167  in the exemplary embodiment. The invention is not so limited, and other types of power sources may be used. The electronic circuitry  3165  of the data processing unit  3105  also includes a processor  3169  communicably coupled to a memory  3171 , a communication module  3173 , and a user interface  3175 . 
     In certain embodiments, the electronic circuitry  3165  may include other components, such as a speaker to provide audible feedback to the user, one or more buttons to receive input from the user, and one or more ports for making a wired connection between the electronic circuitry  3165  and other circuitry external to the data processing unit  3105 . In certain other embodiments, the data processing unit  3105  may be a smartphone, a tablet computer, a laptop computer, and the like, although the invention is not so limiting. In the exemplified embodiment, the electronic circuitry  3165  is located within housing  3163  of the data processing unit  3105 , this housing  3163  being separate and distinct from the housing  3103 A of the toothbrush  3103  In other embodiments, such as that discussed below with respect to  FIG.  38   , the electronic circuitry  3165  or certain components thereof may be located within the housing  3103 A of the toothbrush  3103 . 
     The memory  3171  may be any appropriate type of memory or storage which enables the processor  3169  to perform the desired programming, such as volatile and/or non-volatile random access memory. The particular type of storage used for the memory  3171  is not to be limiting of the invention. 
     In the exemplified embodiment, the user interface  3175  is a touch-sensitive display which accepts input from the user directly on the display surface. The display may be any type of light emitting display, and as shown in the exemplary embodiment, the display may be an LED panel. In certain other embodiments, the display may be an LCD panel, an OLED panel, or any other type of display which is electronically controllable by the programmable processor  3169  to provide visual feedback to the user. As will be discussed below, the user interface is not limited to the exemplary embodiment, but can comprise any device or method by which a user interacts with the data processing unit or a programmable processor. For example, in other embodiments the user interface can utilize a non-touch-sensitive graphical user interface, buttons, a dial, a keyboard, and/or a mouse. In other embodiments, a user interface can be omitted. For example, instead of receiving an oral characteristic by a user interface, oral characteristic data can be received from, or based on, data from a sensor that forms part of a brush. 
     The communication module  3173  may include an antenna  3181  to enable wireless transmission of communication signals. The communication module  3173  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, Bluetooth@, and the like, or it may communicate using any type of proprietary wireless transmission protocol. The mode of communication for which the communication module  3173  is configured is not limiting of the invention unless specifically set forth in a claim. In certain embodiments, the communication module  3173  may include a port to enable communications using wires and wired protocols, such as USB and the like. 
     The communication module  3173  of the data processing unit  3105  may be configured and/or programmed to communicate with the server  3107 . The communication module  3173  may communicate with the server  3107  over any combination of public and/or private network, and the communications may be wired, wireless, or a combination of the two. In certain embodiments, the communication module  3173  may communicate with the server  3107  over the Internet using one or more types of communication protocols. In certain embodiments, the server  3107  may be programmed with one or more application programming interfaces (APIs) which provides server-side functionality to the data processing unit  3105 . The communication module  3173  may also be configured to communicate with the toothbrush  3103 , for example, in the receipt from the toothbrush  3103  of data related to a brushing session. 
       FIG.  36    is a flowchart showing a process  3200  for determining a brushing routine and a brushing evaluation from an oral characteristic according to an embodiment of the invention. In one embodiment, the exemplified process  3200  may be implemented as programming for the programmable processor  3169  of the data processing unit  3105 . For convenience, as part of the description below, reference will also be made to the hardware components of the data processing unit  3105  discussed above in  FIG.  35 B , and means for obtaining brushing session data discussed with respect to  FIGS.  42 - 44   . While in the exemplified embodiment the processor  3169  and other electronic circuitry  3165  form part of the data processing unit, the disclosure is not so limited. For example, in other embodiments, a processor forming part of the toothbrush can carry out the steps carried out by processor  3169  in the embodiments discussed herein. 
     In a first operation, the programmable processor  3169  receives oral characteristic data indicative of an oral characteristic of a user (operation  3202 ). An “oral characteristic” can refer to any quality or trait of or affecting a user’s oral cavity. Such oral characteristics can include, but are not limited to, an oral sensitivity (e.g., of the teeth, gums, or another part of the mouth), an abnormality of the dentiture (e.g., a missing tooth, a crooked tooth, an extra tooth), the presence or absence of wisdom teeth, a receding gum line, a tooth structure that traps (or tends to trap) plaque, plaque present at a first portion of the dentiture, a cavity, an erosion of one or more teeth, an oral injury or procedure (e.g., a recent tooth removal), a type of bacteria present in the mouth (including excessive bacteria or a harmful bacteria), and any indicator (physical, chemical, or otherwise) of a disease or malady (e.g., oral cancer). 
     “Oral characteristic data” can refer to any type of information indicative of an oral characteristic of a user, including information extracted or derived from other information or data indicative of an oral characteristic, regardless of the form of the extracted information, and combinations thereof. The oral characteristic data may be in the form of mathematical data, analog data, and/or digital data. For example, the oral characteristic data can be data obtained from a user interface, data obtained from a sensor, or data derived from one or both of the foregoing. 
     In certain embodiments, the oral characteristic is input at a user interface of a data processing unit. The data processing unit then generates oral characteristic data indicative of the chosen oral characteristic, which is then transmitted to a programmable processor. The receipt of oral characteristic data from a user interface is discussed in more detail below with respect to  FIGS.  37 A and  37 B . 
     In certain other embodiments, the oral characteristic data can be generated using a sensor operably coupled to a programmable processor. The sensor can be any device or subsystem configured to detect an oral characteristic (or evidence of an oral characteristic) and generate oral characteristic data. For example, the sensor can be an accelerometer, a gyroscope, a magnetometer, a pressure sensor, an optical imaging subsystem, and an oral malady detection subsystem. In some embodiments, the sensor can form part of the toothbrush (e.g., an accelerometer located on a head of the toothbrush to detect motion of the brush head). In other embodiments, the sensor can form part of a separate device, such as a data processing unit (e.g., a camera on the phone that can carry out optical imaging to detect a receding gum line or a cavity). 
     For example,  FIGS.  42 - 44    discuss a toothbrush  3351  having electronic circuitry for collecting brushing session data. As is discussed in more detail below, the one or more sensors  3355  can be, for example, an accelerometer, gyroscope, magnetometer, or pressure sensor. The brushing session data that is detected by the sensor may include data regarding, for example, a toothbrush’s position, motion, acceleration, frequency, and/or pressure against the surface of the teeth. The brushing session data can be indicative of numerous issues, such as avoidance of a portion of the dentiture (indicating, for example, an oral sensitivity), excessive brushing (indicating for example, a tooth structure that traps plaque or food), a unique brushing motion (indicating for example, a hidden, crooked, or missing tooth), or the presence or absence of a chemical (indicating, for example, a high bacteria content in the user’s mouth). 
     In one embodiment, the sensors generate brushing session data indicative of brushing motion, location, and/or pressure. This data is then used to determine that the user is avoiding brushing a certain portion of the dentiture, or using only minimal pressure. This avoidance can indicate an oral sensitivity at or adjacent to that portion of the dentiture. To confirm, a user interface, upon receiving such brushing session data, can provide the user a question such as “Do you have oral sensitivity in the region indicated below,” with an image of the user’s dentiture and an indication of the avoided portion. 
     In another embodiment, excessive brushing of a certain portion of the dentiture can indicate a tooth structure that traps plaque or food, such as molars that tend to cause cavities, or a crooked or hidden tooth (i.e., a tooth behind another tooth and difficult to access). If the brushing session data indicates excessive brushing of a certain portion, the user interface can query the user to determine or confirm the reason. 
     In another embodiment, the sensor can determine that the user is using a unique brushing motion for a portion of the dentiture. The user interface can query the user as to whether this motion is being carried out to clean a unique oral characteristic, such as a hidden, crooked, or missing tooth, a gap in the teeth, or another unique property of the user’s dentiture. For example, a user may use a unique, vertical brushing motion to brush a hidden tooth, or may not move the brush as deeply into the oral cavity because of missing wisdom teeth or molars. 
     In another embodiment, the sensor can be an oral malady detection subsystem. For example, a subsystem could use chemistry to determine the presence of an abnormal property, such as high bacteria content in a user’s saliva. Other properties could be indicative of a cavity, plaque, bad breath, or cancer, or another oral disease or malady. 
     In another embodiment, the sensor can be an optical imaging subsystem that can identify a unique oral characteristic, such as receding gum line in a certain area, a missing or crooked tooth, an extra tooth, or a cavity. For example, an imaging system can distinguish the white of a tooth and the pink of gums to determine a length of a gum line and whether there is an abnormality. An imaging system could similarly be used to identify a developing cavity and thus an area that warranted more brushing attention, or tooth erosion from tooth grinding that can cause sensitivity. The subsystem can utilize the technology of a data processing unit providing a user interface (such as the camera and processor of a smartphone), or another, separate device. 
     It is noted that, in some of the embodiments discussed above, the user is queried to confirm that the suspected oral characteristic is present. In other embodiments, this step can be omitted. Further, the sensor(s) can determine a suspected oral characteristic based on data from one brushing session or from a plurality of brushing sessions. Further, the above characteristics can alternatively be determined by querying the user, rather than by using brushing session data provided by sensors. 
     In a further operation, a suggested brushing routine is determined based at least in part on the oral characteristic data (operation  3204 ). The suggested brushing routine can be any one or more steps or instructions for brushing teeth. The determination of the suggested brushing routine may be achieved in any number of ways. In certain embodiments, the suggested brushing routine may be determined by presenting the user with a list of potential brushing routines that accord with the determined oral characteristic, and having the user select the suggested brushing routine from among the list of potential brushing routines. In certain embodiments, the suggested brushing routine may be determined by adjusting a standardized brushing routine based on the oral characteristic data, or by adjusting a time based on the oral characteristic data, as described below. In certain embodiments, the suggested brushing routine may be determined by selecting a predetermined brushing routine based on the oral characteristic data and then adjusting the predetermined brushing routine based on a user brushing history. In such embodiments, the user brushing history may be based upon brushing session data collected from previous brushing sessions of the user. Such brushing session data may be based upon brush stroke, brushing aggressiveness, or upon any other measure of brushing effectiveness. In addition, such brushing session data may be saved in the memory  3171  of the data processing unit  3105  or in a memory of the server  3107 . In still other embodiments, one or more of the aforementioned processes for determining the suggested brushing routine may be used in combination. 
     In one embodiment, the suggested brushing routine is determined by adjusting an optimum brushing time based on the oral characteristic data to determine the brushing time for the suggested brushing routine. In this embodiment, the optimum brushing time is predetermined from a standardized brushing routine. The standardized brushing routine may be an industry standard brushing routine in which the optimum brushing time is 2 minutes. This process can begin with the oral characteristic data being received by the data processing unit  3105 . Next, the data processing unit  3105  determines an offset time based on the oral characteristic data. For example, if a certain portion of the dentiture is sensitive, then the offset time for this portion may be a negative number. Following the offset time determination, the target brushing time for the brushing routine is calculated. As part of this step, the programmable processor  3169  of the data processing unit  3105  calculates the target brushing time by retrieving an optimum time which is stored in the memory  3171  and adding the determined offset time to the optimum time. The determined target brushing time can then be displayed, and the user can be instructed to begin the suggested brushing routine. In certain embodiments, the processor  3169  of the data processing unit  3105  may provide other specific instructions for the brushing routine, such as the order for brushing different sections of the user’s dentiture, the length of time to brush each section, which section to start with, the brushing motions to use for each section, and the like. When the brushing time has expired, the programmable processor  3169  of the data processing unit  3105  can instruct the user that the brushing routine is at an end. 
     In the exemplified embodiment, after determining the suggested brushing routine, there can be a determination of a brushing evaluation based on the oral characteristic data (operation  3206 ). As will be discussed in further detail below, the oral care system  3101  can be configured to perform a brushing evaluation of a brushing session of a user. The brushing evaluation can be any assessment of the effectiveness of one or more brushing sessions. For example, as discussed in  FIGS.  42 - 44   , the toothbrush  3103  can include sensors, and data derived from the sensors can be used to determine the motion, location, and/or pressure of the toothbrush. From this determination, the system  3101  can determine how well the user brushed his or her teeth. In the exemplified embodiment, the evaluation is based in part on the oral characteristic data. Thus, for example, while a brushing evaluation would typically provide a negative evaluation when a certain portion of the dentiture was only brushed for ten seconds or with light pressure, the brushing evaluation according to the invention need not be negative if the user indicated that this was a sensitive portion of the dentiture. Accordingly, the user is not penalized in his brushing evaluation for dedicating less brushing time (or applying softer pressure) to a sensitive area of his dentiture. Thus, in certain embodiments, the determination of the brushing evaluation is based on both oral characteristic data and brushing data from a brushing session, the brushing data being derived from a sensor forming part of the toothbrush. Further, the brushing evaluation can be based on a comparison of the brushing data from the brushing session and the suggested brushing routine. For example, the brushing evaluation can be based on how well the user followed the suggested brushing routine. 
     The oral characteristic data can impact an evaluation of an individual brushing session, and can also impact an evaluation of a plurality of brushing sessions. Thus, while a recent wisdom tooth removal surgery will justify less and more gentle brushing of the molars for a few weeks, there is an expectation that eventually the brushing time and intensity will increase. A cumulative evaluation can reflect this. The cumulative evaluation will not penalize the user for gentle brushing immediately after the surgery, but will also expect more normal brushing to return eventually. 
     In the exemplified method  3200 , the oral characteristic data is used to both determine a suggested brushing routine and determine a brushing evaluation. It is noted, however, that in other embodiments the oral characteristic data can be used to determine a suggested brushing routine but not to determine a brushing evaluation, or to determine a brushing evaluation but not to determine a suggested brushing routine. 
     The following are some examples of determined oral characteristics, and resulting brushing routines and/or evaluations. In one example, if there is a determination that a portion of the dentiture is sensitive, a suggested routine can recommend less time brushing the sensitive portion. Further, an evaluation can expect less time brushing this portion of the dentiture. 
     In another example, if there is a determination of an oral characteristic that warrants excessive brushing of a portion of the dentiture (e.g., a tooth structure that traps plaque or food, such as molars that tend to cause cavities, or a crooked or hidden tooth), a suggested brushing routine can dedicate additional time to this portion of the dentiture. Further, an evaluation can expect additional time brushing this portion of the dentiture. 
     In another example, if there is a determination that a unique oral characteristic warrants a unique brushing motion (e.g., a hidden, crooked, or missing tooth), a suggested routine can adjust its instructions to allow adequate brushing of these unique oral characteristics, including recommending the unique brushing motion. Further, an evaluation can allow for or expect these unique brushing motions. 
       FIGS.  37 A and  37 B  illustrates a data processing unit  3105  having a user interface  3175  for determining an oral characteristic according to one embodiment. In  FIG.  37 A , the user interface  3175  provides a question  3302  and answer options  3304  regarding an oral characteristic. Here, the user inputs the oral characteristic through a user interface  3175  that is a touch-sensitive screen, though alternative types of user interfaces can be utilized. In this embodiment, the user indicates that he has sensitive teeth. In  FIG.  37 B , a statement  330  is provided that is responsive to the answer  3304 . The statement  3306  asks the user which portion of the user’s teeth are sensitive. A visualization of the dentiture  3310  is provided. Here, the user provides a response  3308  indicating that the back molars are sensitive. The questions, answers, statements, and responses shown are merely exemplary in nature, and any oral characteristics can be the subject of a question, answer, statement, or response on a user interface for the purposes of receiving oral characteristic data. In other embodiments, a user can type an oral characteristic and be provided with options that corresponded with the typed oral characteristic. In other embodiments, a series of questions, statements, or topics can be provided to the user by the user interface. For example, the user interface can be used to determine several oral characteristics of the user and in varying degrees of detail. 
       FIG.  38    illustrates a toothbrush  3103 B comprising a user interface  3175 B according to another embodiment of the invention. In this embodiment, the toothbrush  3103 B comprises a user interface  3175 B and a programmable processor (not shown) similar to programmable processor  3169  that forms part of data processing unit  3105 . The user interface  3175 B comprises buttons  3303 B for use in providing or selecting an oral characteristic. The exemplified user interface  3175 B further comprises a display. The display can provide information similar to the information displayed on the touch-sensitive display  3175 . For example, the display can provide information regarding a suggested brushing routine, or brushing evaluation information. In other embodiments, the display can have more limited functionality. In other embodiments, the display can be omitted. In this case, the user can indicate his oral characteristic using the buttons (or another user interface), but the determined routine or evaluation can appear elsewhere, such as on a separate data processing unit. Further, the toothbrush  3103 B can be any type of toothbrush, including a manual toothbrush or an electric toothbrush having an electrically-powered vibratory element. 
       FIG.  39    illustrates a data processing unit  3105  having a user interface  3175  that provides brushing instructions  3510  for a brushing routine according to one embodiment, the instructions  3510  being based in part on the oral characteristic received. In this embodiment, the brushing instructions  3510  comprise real-time directions for a user to follow during a brushing session. The instructions  3510  comprise an indication  3514  of a region of the dentiture to brush, an indication  3512  of a brushing motion, and an indication  3516  of a time remaining for brushing the specified region. In this embodiment, the user interface  3175  also provides an indication  3518  of the total brushing time remaining in the suggested brushing routine. In this embodiment, different screens may show different instructions as the user progresses through the different stages of the brushing routine, thus coaching the user on which regions to brush, which brushing motions to use, and for how long. In other embodiments, certain indications or instructions can be omitted. Also, other indications or instructions can be added, such as an indication of whether to apply greater or lesser pressure or brushing intensity. The instructions (such as motion, region, and time) can be based at least in part on the oral characteristic of the user. Thus, for example, if a first portion of the user’s dentiture was sensitive (or was adjacent to a receding gum line, or included a sensitive eroded tooth), the routine could reflect this by decreasing the brushing time suggested for this first portion of the dentiture, and/or by changing the brushing motions suggested for this portion of the dentiture. Further, if an oral characteristic is a tooth structure that traps plaque, the routine can reflect this by increasing the brushing time for the portion of the dentiture having this tooth structure, and/or by changing the brushing motions suggested for this portion of the dentiture. An evaluation of the brushing session can also reflect such adjusted expectations. 
     The suggested brushing routine can be determined by adjusting a preexisting brushing routine, the adjustment based at least in part on the oral characteristic data. In other embodiments, the suggested brushing routine need not rely on a preexisting brushing routine. The brushing routine of the exemplified embodiment is provided in real-time, so that the user can follow a succession of instructions provided on the user interface  3175 . In other embodiments, the entire routine can be provided at once, and can be provided by other means, such as an email or a text message. 
       FIG.  40    illustrates a data processing unit  3105  having a user interface  3175  that provides an evaluation  3520  of a brushing session of a user according to an embodiment of the invention. In this embodiment, the evaluation  3520  comprises a visualization  3521  of the user’s dentiture. The dentiture can be divided into different regions, each of which the user is expected to brush during the brushing session. Brushing session data may be collected and processed according to the different regions of the dentiture. The collection of such brushing session data is described in more detail below with respect to  FIGS.  42 - 44   . 
     In the exemplified embodiment, the visualization  3521  includes an indication  3522  of a region of the dentiture not properly brushed. The evaluation  3520  further comprises a recommendation  3526  that provides the user advice on how to improve his or her brushing. The evaluation  3520  also includes a performance metric  3524  that indicates how well the user performed in brushing his or her teeth during the brushing session. In other embodiments, other metrics or visualizations can be used to indicate brushing performance, such as a percentage, or a number of stars (for example, three stars out of five). Further, as discussed above, in other embodiments, the evaluation can be a cumulative evaluation based on a plurality of brushing sessions and oral characteristic data from those brushing sessions. 
       FIG.  41    illustrates an electronic toothbrush  3281  according to an embodiment of the invention. The electric toothbrush  3281  includes a handle  3283  and a refill head  3285 . In certain embodiments, the handle  3283  and the refill head  3285  are removably coupled to each other. In certain embodiments of electric toothbrushes, the control circuit  3165  of the data processing unit  3105  may reside at least partially within the handle  3283 . Alternatively, the handle  3283  may include a separate toothbrush control circuit which controls the electric toothbrush and communicates with the data processing unit  3105 . 
     In this embodiment, the refill head  3285  includes a bristle field  3287  which includes at least one elastomeric element  3289  and a tongue cleaner  3291  on the back side  3292  of the refill head  3285 . Also in this embodiment, shown schematically, the handle includes a motor  3294  operably coupled to a shaft  3295 , with an eccentric mass  3297  positioned at the distal end of the shaft  3295 . In combination, the motor  3294 , the shaft  3295 , and the eccentric mass  3297  form an electrically-powered vibratory element. 
       FIG.  42    illustrates a partial sectional view of a toothbrush  3351  having electronic circuitry for collecting brushing session data according to an embodiment of the invention. The handle  3343  of the toothbrush  3341  forms a housing for containing electronic circuitry  3351  for collecting brushing session data. The handle  3343  is a hollow structure in which a cavity  3345  is formed. The electronic circuitry  3351 , which includes a power source  3352 , is located within the cavity. The electronic circuitry  3351  may be used to collect and analyze brushing session data from which an evaluation of the brushing session may be made. In certain embodiments, the evaluation of the brushing session may be based at least in part upon the oral characteristic data. As discussed above, the brushing session data can also be used to determine an oral characteristic. 
       FIG.  43    is a schematic of the electronic circuity  3351  of the toothbrush  3341  of  FIG.  42   . The electronic circuitry  3351  includes a processor  3353  communicably coupled to sensors  3355 , a memory  3357 , and a communication module  3359 . The number of sensors  3355  included as part of the electronic circuitry  3351  depends upon the type of brushing session data to be detected and the functionality of each type of sensor employed. The brushing session data that is detected and collected may include data regarding position, motion, acceleration, frequency, and pressure against the surface of the teeth. Other types of brushing session data associated with a brushing session may also be detected and collected, and those listed herein are not to be limiting of the invention unless otherwise indicated in the claims. In certain embodiments, only one sensor  3355  may be included as part of the electronic circuitry  3351 , and in other embodiments, two or more sensors  3355  may be included. By way of example, the at least one sensor  3355  may be any one or more of the following: a 3-axis accelerometer, a gyroscope, a magnetometer, a pressure sensor, among other types of sensors. In general, each sensor  3355  included as part of the electronic circuitry  3351  generates at least part of the brushing session data. For purposes of the present disclosure, the term “brushing session data” is any type of information which may be extracted or derived from a sensor or sensor signal, regardless of the form of the extracted information, for determining information about a brushing session of a user. By way of example, brushing session data may be in the form of mathematical data (such as a formula which mathematically represents at least part of the sensor signal), analog data (such as the waveform of the sensor signal), and/or digital data (such as a representation of at least part of the sensor signal in a digital format). In certain embodiments, the processor  3353  and the memory  3357  may be omitted from the electronic circuitry  3351  of the toothbrush  3341 . In such embodiments, the sensors  3355  may communicate brushing session data directly to the communication module for transmission. 
     The memory  3357  may be any appropriate type of memory or storage which enables the processor  3353  to perform the desired programming, such as volatile and/or non-volatile random access memory, or any other type of storage. The particular type of storage used for the memory  3357  is not to be limiting of the invention. The communication module  3359  in the exemplary embodiment includes an antenna  3361  to enable wireless communication. The communication module  3359  may be configured and/or programmed to communicate using a wireless technology standard such as Wi-Fi, BluetoothⓇ, and the like, or it may communicate using any type of proprietary wireless transmission protocol. In certain embodiments, the communication module  3359  may include a port to enable communications using wires and wired protocols, such as USB and the like. The particular mode of communication used by the communication module is not limiting of the invention unless specifically set forth in a claim. 
       FIG.  44    illustrates a toothbrush dongle  3391  for collecting brushing session data. Generally, the toothbrush  3381  includes a handle  3383  and a head  3385  to which a plurality of teeth cleaning elements  3387  are affixed. The dongle  3391  may be removably affixed to the proximal end  3389  of the handle  3383 . The dongle  3391  comprises a housing for containing electronic circuitry  3393  and an associated a power source  3395 , which may be similar to that described above in connection with  FIG.  43   . 
     The brushing session data which is detected and collected by the toothbrush embodiments shown in  FIGS.  42 - 44    may include a side-to-side linear brush stroke motion, an up and down linear brush stroke motion, a circular brush stroke motion, a flicking brush stroke motion, a brush stroke rate, and a pressure of the head of the toothbrush on the teeth, amongst others. During use, the brushing session data is generated during at least a portion of the brushing session. The brushing session data may be used to evaluate the brushing session by calculating one or more performance metrics, and the performance metric may represent brushing efficacy during one or more portions of the brushing session. The performance metric may express the efficacy of a brushing session, or even for portions of a brushing session, as a single number, and stored in the memory  3171  of the data processing unit  3105  for later use. In certain embodiments, the data processing device  3105  may transmit the calculated performance metrics to the server  3107  for storage and or additional analysis. 
     In certain embodiments, the performance metrics which are stored in the memory  3171  of the data processing unit  3105  or on the server  3107  may be used during future brushing sessions to aid in determining what brushing routine to suggest to the user. For example, performance metrics may be used in combination with the oral characteristic data to help determine the target brushing time for a brushing routine. Also, in embodiments in which performance metrics are stored, the performance metrics may be analyzed by machine learning processes, and the machine learning may be used to enhance future brushing routines. 
     The embodiments above discuss using oral characteristic data to determine a brushing routine and/or evaluation. Note that the routine or evaluation can also be based on other factors, such as predetermined brushing standards (e.g., two minutes of total brushing time and recommended brushing motions for different portions of the dentiture), physical characteristics of the brush being used by the user (e.g., soft or hard bristles, or the shape and/or size of the toothbrush head), and the user’s brushing goals for a given brushing session (e.g., a quick fresh as opposed to a deep clean). 
     In certain embodiments, the user can use the data processing unit while brushing his teeth to receive real-time instructions for the brushing routine. In such instances, the brush and the data processing unit can be in communication. In other instances, the brush can be used without the data processing unit, and/or without a processor immediately determining a brushing routine or evaluation. For example, the brush can store brushing session data locally in the toothbrush, and this data can be retrieved at a later time. This stored brushing session data can subsequently be used for providing a brushing evaluation or suggested brushing routine, and/or for suggesting potential oral characteristics. 
     The disclosed embodiments provide several advantages. For example, the system can provide a brushing routine that takes into consideration the unique oral characteristics of the user. Thus, the brushing routine provided can reflect oral characteristics of the user, rather than providing the same standard routine regardless of the user. Further, the system can provide a brushing evaluation that takes into consideration the oral characteristics of the user. Thus, an evaluation can be based on the user’s unique oral characteristics, rather than judging the brushing session based on an unadaptable, one-size-fits-all standard. For example, if a user has a first portion of the dentiture that is sensitive and is adjacent to a receding gum line, the suggested routine can dedicate less brushing time to this first portion, and can avoid penalizing the user for spending less than a standard time brushing this portion. Alternatively, if a user still has his or her wisdom teeth, the suggested routine can dedicate more time to the back molars, and the evaluation can expect that the user’s brushing motion reaches further back in the oral cavity when brushing the back molars. 
     As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by referenced in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls. 
     While the invention or inventions have been described with respect to specific examples, those skilled in the art will appreciate that there are numerous variations and permutations of the above described invention(s). It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention(s). Thus, the spirit and scope should be construed broadly as set forth in the appended claims.