Patent Publication Number: US-2021161616-A1

Title: Dexterous Dental Handpiece With Hand and Foot Actuation

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/444,672 entitled “Dexterous Dental Handpiece With Finger And Toe Actuation” filed Jan. 10, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This disclosure relates to a dental handpiece for dexterous operability with hand and foot actuation. 
     2. Description of the Related Art 
     Currently, dental drills are actuated by the dental practitioner by means of a foot switch or pedal. This switch is relatively large, positioned in the foot space of the dental practitioner, and has a number of wiring and tubing connections for supply and delivery of compressed air, coolant water and electrical lighting. This design requires the dental practitioner to operate it from a sitting position for most sensitive foot control; whereas when standing the pressure points are not as sensitively felt. If the dental practitioner has to change his position with respect to the patient, the dental practitioner may also have to reposition the foot switch. 
     What is needed therefore is a dental handpiece with hand as well as foot control that provides for unfettered control through the elimination of the traditional foot switch needed for dental drills. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a dental handpiece for dexterous operability with hand and foot operation. Non-limiting examples of which are finger and toe actuation, toe and heel operation, finger and heel operation, among others. In one embodiment, the dental handpiece includes a pneumatic dental drill system in which the traditional foot switch is eliminated. One actuating sensor can be located at the handpiece and a second actuating sensor with wireless transmitter can be placed at the tip or heel of the dental practitioner&#39;s shoe to produce independent signals that are processed in an electronic controller. The controller then drives an actuator that controls the airflow to the handpiece. The sensors may be operated separately or simultaneously. The pressure points threshold, or sensor sensitivity, can be adjusted to best suit the dental practitioner. The sensors can be ambidextrous. 
     According to some embodiments, the disclosure provides a dental instrument comprising a fluid driven handpiece in fluid communication with a valve, a source of fluid in fluid communication with the valve, and a controller in electrical communication with the valve and an actuating sensor positioned on the handpiece. The sensor may be configured to cause the valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows from the source of fluid to the handpiece thereby driving the handpiece. The dental instrument may further comprise a second actuating sensor in communication with the controller. The second sensor may be configured to cause the valve to move between the first position in which fluid cannot flow from the source of fluid to the handpiece and the second position in which fluid flows from the source of fluid to the handpiece thereby driving the handpiece. 
     According to some embodiments, the disclosure provides a dental instrument comprising a fluid driven handpiece in fluid communication with a metering valve, a source of fluid in fluid communication with the metering valve, and a controller in electrical communication with the metering valve and an actuating sensor positioned on the handpiece. The actuating sensor may be configured to cause the metering valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows freely from the source of fluid to the handpiece and between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. The dental instrument may further comprise a second actuating sensor in communication with the controller. The second actuating sensor may be configured to cause the metering valve to move between the first position in which fluid cannot flow from the source of fluid to the handpiece and the second position in which fluid flows freely from the source of fluid to the handpiece and between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. 
     In some embodiments, one or more supply lines and one or more electrical wires may be positioned within the fluid driven handpiece. An umbilical may be configured to receive one or more supply lines and one or more electrical wires, the umbilical selectively attachable to a distal end of the fluid driven handpiece. The one or more supply lines and one or more electrical wires of the fluid driven handpiece may be selectively attachable to the one or more supply lines and one or more electrical wires of the umbilical. In some embodiments, the one or more electrical wires of the fluid driven handpiece are selectively attachable to the one more electrical wires of the umbilical via stationary contact pads on a distal face of the fluid driven handpiece and contact bumps on the proximal face of the umbilical. The one or more electrical wires of the fluid driven handpiece may be selectively attachable to the one more electrical wires of the umbilical via a transmitter coil of the fluid driven handpiece and a receiver coil of the umbilical. 
     In some embodiments, the second actuating sensor may be in wireless communication with the controller. The second actuating sensor may comprise a wireless device dimensioned to be secured to a toe or heel of a shoe. The wireless device may comprise a pressure sensor in electrical communication with a transmitter. The wireless communication may be using a secure wireless communication protocol such as IEEE 802.11 a/b/g/n using encryption for security and safety. 
     According to some embodiments, the disclosure provides a fluid driven handpiece in fluid communication with a valve, a source of fluid in fluid communication with the valve, a controller in electrical communication with the valve and an actuating sensor. The actuating sensor may comprise a wireless device dimensioned to be secured to a toe or heel of a shoe, and the actuating sensor may be configured to cause the valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows from the source of fluid to the handpiece thereby driving the handpiece and optionally between one or more intermediate positions where the fluid flows at different speeds thereby driving the handpiece at different speeds. The wireless device may comprise a pressure sensor in electrical communication with a transmitter that communicates a signal proportional to the exerted pressure. The wireless communication may be using a secure wireless communication protocol such as IEEE 802.11 a/b/g/n using encryption for security and safety. 
     According to some embodiments, the disclosure provides a fluid driven handpiece in fluid communication with a valve, a source of fluid in fluid communication with the valve, a controller in electrical communication with the valve and an actuating sensor positioned on the handpiece, a second actuating sensor in communication with the controller, the second actuating sensor being configured to cause the valve to move between the first position in which fluid cannot flow from the source of fluid to the handpiece and the second position in which fluid flows from the source of fluid to the handpiece thereby driving the handpiece and optionally between one or more intermediate positions where the fluid flows at different speeds thereby driving the handpiece at different speeds, one or more supply lines and one or more electrical wires positioned within the fluid driven handpiece, an umbilical configured to receive one or more supply lines and one or more electrical wires, the umbilical selectively attachable to a distal end of the fluid driven handpiece. The controller may control the actuator of the valve electromagnetically, and the actuator may be configured to cause the valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows from the source of fluid to the handpiece thereby driving the handpiece. The actuator of the valve may be a solenoid coil that actuates the valve. 
     Additionally, the fluid driven handpiece may be in fluid communication with a metering valve, a source of fluid in fluid communication with the metering valve, and a controller in electrical communication with the metering valve and an actuating sensor positioned on the handpiece. The actuating sensor may be configured to cause the metering valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows freely from the source of fluid to the handpiece and optionally between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. The dental instrument may further comprise a second actuating sensor in communication with the controller. The second actuating sensor may be configured to cause the metering valve to move between the first position in which fluid cannot flow from the source of fluid to the handpiece and the second position in which fluid flows freely from the source of fluid to the handpiece and optionally between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. The one or more supply lines and one or more electrical wires of the fluid driven handpiece may be selectively attachable to the one or more supply lines and one or more electrical wires of the umbilical. 
     It is therefore an advantage of the disclosure to provide a dental handpiece for dexterous operability with hand and foot actuation. 
     These and other features, aspects, and advantages of the present disclosure will become better understood upon consideration of the following detailed description, drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an actual prototype system overview with breadboard base station, drill with finger sensor, and shoe with exemplary wireless toe sensor for an example embodiment of the disclosure. 
         FIG. 2  shows a dental drill with detachable finger pressure sensor according to an example embodiment of the disclosure. The “S” loops are cable strain reliefs to allow for rotational movement (left loop) and tube flexing (right loop). The thin coaxial cable is run through the large air lumen still allowing ample air flow. A stainless steel clip holds the connector tightly to the handpiece. 
         FIG. 3  shows a detachable finger pressure sensor tied to dental drill of  FIG. 2 . 
         FIG. 4  shows a stainless steel clamp on dental drill to hold the connector tightly to the handpiece of  FIG. 2 . 
         FIG. 5  shows a coaxial sensor cable inserted into air lumen of tubing through a modified coupling still allowing air flow for the dental drill of  FIG. 2 . 
         FIG. 6  shows an elastic cycling toe cover slipped over a dental practitioner&#39;s shoe, top (left) and bottom (right) view. The main pressure point of the sole remains uncovered for comfort and safety. It can come in a one-size-fits-all format. 
         FIG. 7  shows perspective views of a detachable toe pressure sensor with wireless transmitter. The sensor is attached to the dental practitioner&#39;s shoe with a strip of hook and loop fastener material such as that sold under the tradename Velcro®. 
         FIG. 8  shows the toe pressure sensor with wireless transmitter of  FIG. 7  attached to the dental practitioner&#39;s shoe with a Velcro® strip and rubber band. 
         FIG. 9  shows a prototype system breadboard front (left) and back view (right) according to an example embodiment of the disclosure showing the arrangement of a base station, air valve, light delay circuit and tubing clamp. The base station&#39;s cover has been opened in the left view to show the electronics inside. 
         FIG. 10  shows the base station front (left) and rear panel (right) of the system of  FIG. 9 . The dental practitioner adjusts the pressure sensitivity independently for the finger and toe or heel sensors. All electrical connections can be made in the back. A 900 MHz whip antenna is mounted on the enclosure. 
         FIG. 11  shows the circuit board inside the base station of  FIG. 9  showing the component layout on the circuit board. 
         FIG. 12  is a schematic of a power supply, hand logic, foot logic, and air valve driver according to an example embodiment of the disclosure. 
         FIG. 13  is a schematic of a signal conditioning of hand pressure sensor and associated threshold discriminator according to an example embodiment of the disclosure. 
         FIG. 14  is a schematic of a signal conditioning of a transmitter, receiver, demodulator, and veto safety circuit according to an example embodiment of the disclosure. 
         FIG. 15  is a schematic of a foot pressure signal discriminator according to an example embodiment of the disclosure. 
         FIG. 16  shows a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. 
         FIGS. 17A and 17B  show a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation and a cross-sectional view along the line  17 B- 17 B respectively, according to another example embodiment of the disclosure. 
         FIGS. 18A and 18B  show a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. 
         FIG. 19  shows a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. 
         FIGS. 20A and 20B  show a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. 
         FIG. 21  shows a schematic depiction of a dental handpiece for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. 
     
    
    
     Like reference numerals will be used to refer to like parts from Figure to Figure in the following description of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     An overview of the system components of a non-limiting example embodiment of the disclosure is shown in  FIG. 1 . The system  10  includes a pneumatic drill  20  retrofitted with a detachable finger pressure sensor  22  (left), an exemplary toe cover  30  slipped over a shoe  32  and having the pressure sensor  34  with a wireless transmitter  36  attached via Velcro® (right) and a breadboard with base station controller, actuator valve, lighting unit and tubing and electrical interconnects (center). The base station  40  has the cover  44  removed to expose the electronic board  46  inside. The RF antenna  48  to communicate with the shoe transmitter is mounted on top of the metal cover. The system is supplied with compressed air of approximately 30 psi pressure, optional coolant water, 12VDC/1A electrical power to the base station, 9VDC/2A electrical power to the lighting unit, and a CR2450 coin battery for the toe sensor. The toe cover  30  could be modified to cover the heel of a subject to be used for heel activation as well, 
     A pneumatic turbine drill can be used and a detachable pressure sensitive resistor can be clamped to the handpiece. In  FIG. 2 , there is shown the handpiece  20  with pressure sensor  22 , the connecting cable  24  that is incorporated into the large air lumen of the supply tubing and a connector  25  with custom-made stainless steel clip  26  to hold the connector and cable tightly against the drill. The pressure sensor  22  is attached to the handpiece  20  with short sections of transparent shrink tubing. Alternatively, the shrink tubing can be replaced with custom-made stainless steel clips. As long as the sensor  22  is attached to the exterior of the handpiece, the sensor  22  is preferably detachable for autoclaving of the drill. Alternatively, the sensor can be incorporated into. the handpiece under a thinned-out area of the handpiece housing. In this alternative embodiment, there will be no cable external of the drill and the electrical connections can be made via the standard handpiece connector. The S-shaped loops of the cable  24  are strain relief features to allow limited twisting of the handpiece against the tubing. The cable  24  is a special coaxial cable with a polytetrafluoroethylene (e.g., Teflon®) cable jacket to reduce friction. The stainless steel clamp  26  has a cutout that is shaped such that the cable connector will be held together, in essence serving as a detent. The sensitive area of the pressure sensor  22  is positioned on the handpiece axially and radially such that a right-handed dental practitioner will have the most ergonomic control of the switch. For a left-handed dental practitioner, the sensor  22  may be repositioned as needed. A close-up of the pressure sensor is shown in  FIG. 3 , a close-up of the connector clamp  26  is shown in  FIG. 4 , and a close-up of the cable insertion into the air lumen  28  of the tubing is shown in  FIG. 5 . 
     An alternative dental drill actuation mode through foot operation was realized freeing the finger of the dental practitioner. Also, since most dental practitioners are trained to use their foot to operate the drill, this option offers the dental practitioner a familiar but advanced actuation method, acting as a go-between to the as-of-yet unfamiliar finger actuation. 
     To maintain an advantage of the present disclosure of avoiding the large foot switch with its many connections, the foot pressure sensor was designed as a small, detachable, wireless device  34  that can be ergonomically positioned in the toe area of the dental practitioner&#39;s foot. In some embodiments, the wireless device  34  can be ergonomically positioned in the heel area of the dental practitioner&#39;s foot as well. The wireless device  34  attaches to a toe or heel cover  30  that is slipped over the dental practitioner&#39;s shoe  32  as shown in  FIG. 6 . The main pressure point of the sole  33  remains uncovered for comfort and safety. The attachment is made with Velcro® strips to allow optimal positioning of the pressure sensor for best ergonomic operation. In  FIG. 7 , the compact and self-contained wireless device is shown. The transmitter, associated electronics, and battery compartment are densely packed around a double-sided printed circuit board. The wireless device  34  is ruggedized by two layers of black shrink tubing  35  with cutouts for protrusions of the whip antenna, an on-off switch, and a cutout for a red LED light (just below the toggle lever) to indicate that the wireless device is powered on. In addition to LED light at toe or heel sensor operation, a vibratory feedback device is included to indicate the activation of the toe or heel sensor to the user. The on-off switch can be chosen to be a “hard” switch, meaning that in the off position zero current is flowing to prevent battery drain, The battery easily slides in-and-out of the battery compartment and yet is held firmly in place by spring-loaded contacts. The pressure sensor  39  is beneath the Velcro® strip  38  with its sensitive area approximately in the center of the strip  38 . The Velcro® serves also to ruggedize by protecting the sensor. The nearly half-circular pre-shaped transparent shrink tubing contains the electrical connection and affords a relatively stiff but flexible connection between the sensor and the transmitter electronics. It is shaped to conform to the curvature of the tip of a shoe  32  and is slightly over-bent to provide a snug adherence to the shoe surface. The transmitter  36  can be affixed even tighter to the shoe by applying a rubber band  37  as shown in  FIG. 8 . The range of the transmitter can be approximately 50 feet. 
     In  FIG. 9 , there is shown the prototype breadboard with the arrangement of the stationary system components of an example embodiment of the disclosure. The main components mounted to the board are the base station control electronics  46 , the air actuator valve, and the lighting power supply. In the front, there is a wooden clamp to firmly hold the tubing to the dental drill in place. The main electronics box with its front panel controls is placed next to the clamp. In the back, there are ports and connections for the supply of DC power, compressed air, and coolant water. 
     In  FIG. 10 , there is shown the front and back panels of the electronics box with main power switch, LED power indicator, and two independent sensitivity adjustments  51 ,  52 , for the hand sensor and the foot sensor, respectively. Each sensor may be enabled or disabled with toggle switches with all combinations possible. A 900 MHz whip antenna  48  is mounted on top of the metal electronics enclosure for unimpeded RF reception. 
     The component layout of the circuit board  46  is shown in  FIG. 11 . To aid in the development process of the circuit design, several trimmer resistors were included throughout the circuitry to allow fine-tuning of operational parameters during field-testing. 
     A non-limiting example electronic circuit design is shown in the schematics of  FIG. 12  through  FIG. 15 . In the schematic of  FIG. 12 , the circuit includes: a 12V power supply, uncritical regulated or unregulated  102 ; a 5V power supply, critical, regulated  104 ; a panel indicator, on-off  106 ; foot logic with wireless veto to prevent air valve actuation when the transmitter is turned off  108 ; foot logic with power-on delay to prevent air valve actuation from an undefined state at start-up  110 ; hardware disable of hand and/or foot enable signal  112 ; 0red foot and hand logic  114 ; an air valve solenoid  115 ; an air valve solenoid indicator  116 ; and an air valve solenoid driver circuit  118 . 
     Still referring to  FIG. 12 , 12VDC power at 1A is supplied through a standard 2.5 mm DC jack CON 1 . The “hard” power switch on the front panel connects or disconnects the entire circuit to this power rail. Downstream from the power switch is an LED power indicator followed by a 5V voltage regulator U 2 . The unregulated 12V power rail provides power to the solenoid valve Sol 1  via the connector J 1 /J 2 . The output of the voltage regulator U 2  provides voltage-stabilized power to the analog and digital circuits. The air valve is actuated with a driver circuit using a MOSFET switch Q 1  in an open-drain configuration. The gate of Q 1  is driven directly by an OR gate U 3 A that ORs the digital signals from the discriminators of the Hand and Foot Enable signals. These signals may be independently disabled in hardware by removing the jumpers JP 1  and JP 2 . The Foot discriminator signal may require a special provision for unwanted switching during transitory conditions such as system Power-On and when the foot transmitter is turned off (no RF carrier resulting in high-frequency FM demodulation artifact). The former can be prevented by a special inverted FOOT_VETO signal ANDed with the regular Foot discriminator signal in gate U 1 A. The latter is prevented by an RC delay circuit consisting of R 2  and C 1  with a time constant of τ=40 μs. Both, the delayed Power-On signal and the Foot Enable signal are ANDed in U 1 B to produce the protected Foot Enable signal. Before Power-On, R 5  assures that C 1  is fully discharged. At the moment of Power-On, any fast transitory Foot Enable signal will not result in a momentary opening of the air valve because the Power-On Delay signal has not reached it high state yet and thus the output of U 1 B will remain low. In less than 1 ms after Power-On, all transitory Foot Enable signals have passed and the Power-On Delay signal remains high henceforth, effectively directly connecting the Foot Enable signal to the Foot and Hand Logic OR. 
     The circuitry producing the hand discriminator signal HAND_DISC is shown in  FIG. 13 . In the schematic of  FIG. 13 , the circuit includes: a pressure-sensitive resistor  122  at the headpiece, idle—10.5 k, full pressure≃6 k; a pre-adjusted lower hand threshold and hysteresis  124 ; a level transistor (gain≃5×)  126 ; and a lower hand threshold (on panel)  128 ; and a threshold discriminator with adjustable hysteresis  132 . The pressure-sensitive resistor R 7  connects through J 3 /J 4  to a voltage divider circuit consisting of R 7  and R 8  driven by the stable 5V rail, The dividing point is input into a level translator U 4  with 5× gain and pre-adjustable level through R 9 . The amplified and level-adjusted output is voltage-divided with the R 11 /R 12  resistor circuit with R 12  being the Hand Sensor Sensitivity potentiometer on the front panel of the electronics box. The slider of R 12  feeds the input of a special threshold discriminator U 5  with adjustable hysteresis through R 11 . Both outputs of U 5 , OUTA and OUTB, have LED indicators connected to them for development purposes. At terminal OUTA, the HAND_DISCR signal is available. 
     The circuits related to a non-limiting example foot switch are shown in  FIG. 14 . In the schematic of  FIG. 14 , the circuit includes: a rechargeable button cell CR2450 110 mAh  142 ; a low-dropout voltage regulator  144  to supply stable voltage to data generation circuitry independent of battery charge state; a pressure-sensitive resistor  146  at shoe tips, idle≃5 kΩ, full pressure≃500Ω; a resistance-to-frequency converter  148 ; square wave serial data modulation  152  (&lt;kHz, 50% duty); serial data generation  154 , PSR idle≃1.5 kHz, PSR full pressure≃14 kHz; an FM transmitter  156 ; an FM receiver  158 ; wherein at  162 , when TX is on: square wave demodulated serial data (F&lt;15 kHz); a frequency-to-voltage converter  164 ; wherein at  166 , when TX is off: square wave white noise, no modulation (f&gt;50 kHz); a high-pass filter plus buffered rectifier  168  producing a DC signal proportional to frequency wherein high-frequency white noise produces a substantially larger DC voltage when TX is off compared to when TX is on and frequency is &lt;15 kHz wherein this signal is used to generate a veto signal to prevent air valve from opening when TX is off; a Schmitt-trigger  172  to create a digital veto signal from analog DC voltage of the high-pass filter; and wherein at  174 , when TX on, V≃3.84V and when TX is off, V≃0.02V. 
     Still referring to  FIG. 14 , the circuits can be divided into those of the transmitter located at the tip of the dental practitioner&#39;s shoe and those of the receiver located in the base station. Beginning with the former, the coin battery BT 1  supplies the entire transmitter circuit with 3.6V unregulated power through a “hard” switch SW 2 . D 6  is a red LED indicator that is lit during the Power-On state and helps the operator to clearly see if the device is powered on or off so not to accidentally discharge the battery needlessly. The battery voltage is downregulated to 3.3V with the voltage regulator U 7 , which supplies the resistance-to-frequency converter and FM transmitter ICs. The pressure-sensitive resistor R 26  connects directly to terminals  1  and  5  of the resistance-to-frequency converter U 9 . This IC outputs a square wave of &lt;15 kHz at 50% duty cycle, which actually varies between 1.5 kHz and 14 kHz, depending on whether the pressure sensor is subjected to “full pressure” (highest expected pressure from the dental practitioner&#39;s foot) or no pressure, respectively. This square wave is used as modulation for the FM transmitter, not unlike the frequency-shift-keying (FSK) modulation mode. The FM transmitter comprises a single IC U 11  that takes the modulation signal through a blocking capacitor C 12  and outputs the FM-modulated 900 MHz carrier wave through the antenna A 2 . The FM-modulated wireless signal interference is secure from interference from other wireless signals. 
     The base station receives this signal though the whip antenna A 1  mounted on top of the metal enclosure of the electronics box. A 1  connects directly to the single IC FM receiver U 6 , which outputs the FM-demodulated signal on its DATA port at pin  12 . Significantly, when the transmitter is powered-on, the demodulated signal will be a square wave between 1.5 kHz and 14 kHz. 
     However, if the transmitter is powered-off, there is no clear demodulated signal and the DATA port outputs white noise of a frequency greater than 50 kHz. This situation poses a problem because during normal operation the variable square wave is processed in the frequency-to-voltage converter U 8  to generate the FOOT_PRESSURE_ANALOG_SIGNAL used in the Foot discriminator. Therefore, if a 50 kHz signal is presented to U 8  it will generate a high voltage output, which the discriminator will interpret as “full pressure”, even though the transmitter is powered-off. To veto this condition, the DATA port output of U 6  is split into a high-pass filter comprising C 6  and R 19  with a time constant of τ=5 μs followed by a rectifier D 7  and filter C 8 . The RC high-pass has a high input impedance so the adjustable load resistor R 24  puts an effective clamp on the rectified voltage without undue load on the DATA signal itself. When R 24  is properly adjusted, the voltage input into the Schmitt-trigger U 10 A at pin  2  is reliably &lt;0.80 V when the transmitter is powered-on and rises to 1.16 V when the transmitter is powered-off. The difference in these voltages is used to extract with certainty the information whether the transmitter is powered-on or powered-off. The Schmitt-trigger U 10 A, when properly adjusted with the level adjuster R 28 , produces a reliable FOOT_VETO signal when the transmitter is powered off. 
     The FOOT_PRESSURE_ANALOG_SIGNAL is processed and converted into the foot discriminator signal FOOT_DISCR with the circuit shown in  FIG. 15 . In the schematic of  FIG. 15 , at  176 , when the foot is off the ground, the voltage=0.4V; when the foot is resting on the front sole, the voltage=1.0V; when there is a fully tilted foot (=30°) and no pressure, the voltage≃2.9V, and when there is a fully tilted foot (=30°) and full pressure, the voltage≃=3.6V. The signal is voltage-divided and level-adjusted by resistors R 32  and R 33  with the latter being the Foot Sensor Sensitivity control potentiometer on the front panel of the electronics box. The level-adjusted FOOT_PRESSURE_ANALOG_SIGNAL is input into a 2-operational amplifier instrumentation amplifier consisting of U 10 B and U 12 A with a gain of 3×. The output at pin  7  of U 10 B is voltage-divided by a fixed resistor series network consisting of R 38 , R 39 , R 40  and R 41 . The divided signal is tapped between R 39  and R 40  and is input into the discriminator circuit U 13  with R 43  being a hysteresis adjustment. The states of both outputs OUTA and OUTB at pin 1  and pin 8 , respectively, are indicated by LEDs D 8  and D 9  to aid in the development process. The FOOT_DISCR signal is output OUTA available at pin 1 . 
     Turning now to  FIG. 16 , another embodiment of a handpiece  70  is shown. The handpiece  70  incorporates a pressure sensor  72  and supply lines  74  into the handpiece housing  71  and an umbilical  73  extending from a distal end of the handpiece  70 . One advantage of this design is that the sensor and wiring is protected and no exterior surfaces (i.e., the sensor element, wiring and electrical connector) are added to the system that may get contaminated. Cleaning and disinfection of the exterior of the handpiece  70  may be simplified and the handpiece  70  may be autoclaved without having to remove the sensor  72  and associated supply lines  74  beforehand. The sensor  72 , supply lines  74  and electrical connector  76  are schematically shown half-transparent to indicate their location inside the handpiece  70  and inside a lumen of the umbilical  73 . The function of the components remains the same as with the embodiment that has the sensor  22 , cable  24  and connector  25  attached externally to the handpiece  20  and lumen  28 . 
     Turning now to  FIGS. 17A and 17B , in order to facilitate a mechanical means of transmitting the finger pressure of the physician to the pressure sensor  72  located in the interior of the handpiece  70 , a section of the handpiece housing  71  has a thin-walled section  78  to the extent that normal finger pressure will deform the thin-walled section  78  of the housing. The thin-walled section  78  is preferably shaped such that it accommodates the shape of the pressure sensor  72 , specifically its sensitive area. In  FIGS. 17A and 17B , the sensor  72  is shown as having a circular, disc-like shape. In such a case, the thin-walled section  78  of the handpiece housing  71  is also generally circular in shape in order to accommodate the shape of the sensor  72 . As illustrated in  FIG. 17B , the pressure sensor  72  is bonded to the thin-walled section  78  on an interior surface of the handpiece housing  71 . There is a small gap  79  between the edge of the sensor  72  and the end of the thin-walled section  78  such that a deformation of the thin-walled section  78  does not push the sensor  72  against the portion of the handpiece housing  71  that is not thinned-out. 
     The thickness of the thin-walled section  78  is determined by the optimal finger pressure profile and also the optimal deformation for the bonded sensor  72 . In a preferred embodiment, the wall thickness of the thin-walled section  78  is thin enough to cause a suitable deformation at comfortable finger pressure and at the same time thick enough to retain the ruggedness of the handpiece  70 . The thin-walled section  78  of the handpiece housing may be configured as a plug that can be inserted into the handpiece  70  and preferably being situated flush with the exterior of handpiece housing  71 . This configuration would allow optimization of the pressure area  80  in combination with the sensor  72  bonded to it. 
     Turning now to  FIGS. 18A and 18B , another embodiment of the handpiece  70  is shown with the supply lines  74  and electrical wiring  75  positioned inside the handpiece housing  71  and the umbilical  73 . The electrical connector  76  shown in  FIG. 16  is replaced with a pair of stationary connector pads  82  on distal face  84  of the handpiece  70  and a mating pair of spring-loaded contact bumps  86  on the proximal face  88  of the umbilical  73 . The supply lines  74  (which may include air, water, and fiber optic light guide, among others) include protruding line sections  90  that mate with receptacles  92  positioned within the umbilical  73  configured to create a sealed connection between the receptacles  92  and protruding line sections  90  thereby creating continuous supply lines  74  when the connection is made. 
     The stationary connector pads  82  may be located on the distal face  84  of the handpiece  70  in order to embed the connector pads  82  into the distal face  84  of the handpiece  70  and thereby permanently sealed in place. If the connector pads  82  are inserted flush with the distal face  84  of the handpiece  70  then the cleaning and disinfection process is simplified because no crevices are created where access to disinfectant or mechanical cleaning might be impeded. 
     To facilitate reliable electrical connection and allow some relative movement between the handpiece  70  and the umbilical  73  during operation, the mating connections of the stationary connector pads  82  are made as spring-loaded contact bumps  86 . The spring-loading travel and force is determined by the degree of relative movement that needs to be accommodated while still maintaining reliable electrical connection between the stationary contact pads  82  and the spring loaded contact bumps  86 . 
     The contact bumps  86  may be spring-loaded with an actual coil or leaf spring or an elastomeric material. These materials may produce a smooth transition from the contact bumps  86  to the proximal face  88  of the umbilical  73  avoiding any crevices in the mechanism that might make disinfection and cleaning more difficult. 
     Turning now to  FIGS. 19, 20A, and 20B , another embodiment of the handpiece  70  is shown. The handpiece  70  is modified to have a contact-less quick-disconnect that replaces the electrical connector  76 . The above disclosed stationary connector pads  82  and contact bumps  86  can be expected to be a rugged and reliable method for electrical contact. 
     Another embodiment that may increase the service life of the system by incorporating electromagnetic communication between the sensor inside the handpiece and the control unit is disclosed.  FIG. 20B  shows the location of the contact-less electromagnetic communication and unique device identifying protocol interface  95  at the same location as the previously-described connector pads  82  and contact bumps  86 . 
     The supply lines  74  (which may include air, water, and fiber optic light guide, among others) remain the same as described above. However, the contact pads  82  on the distal face  84  of the handpiece  70  as well as the contact bumps  86  on the proximal face  88  of the umbilical  73  are replaced with a transmitter coil  96  just behind the distal face  84  of the handpiece  70  such that it may be adjacent to and/or abut with the inside wall of the handpiece body  71  at the distal face  84 , and a receiver coil  98  umbilical just behind the proximal face  88  of the umbilical  73  such that it may be adjacent to and/or abut with the inside wall of the umbilical  73  at the proximal face  88 . When the umbilical  73  is connected to the handpiece  70 , the transmitter coil  96  and the receiver coil  98  are positioned in close proximity, which affords a tight electromagnetic coupling. This tight electromagnetic coupling enables efficient energy and/or information transfer between the circuit inside the handpiece  70  and the circuit in the controller unit (not shown). 
     The controller unit can perform a number of functions, one non-limiting example of which is the interruption/control of a fluid flow through the supply lines  74 . The controller unit can control one or more fluids flowing through the supply lines  74  that can serve a number of purposes, including but not limited to: driving the handpiece  70  if the handpiece  70  includes a drill, for example, pumping fluid through the supply lines  74  to be administered though the handpiece  70 , guiding light for illumination through light guides, among other things. 
     According to some embodiments, the handpiece  70  may be in fluid communication with a metering valve, A source of fluid may be in fluid communication with the metering valve, and a controller may be in electrical communication with the metering valve and an actuating sensor positioned on the handpiece. The actuating sensor may be configured to cause the metering valve to move between a first position in which fluid cannot flow from the source of fluid to the handpiece and a second position in which fluid flows freely from the source of fluid to the handpiece and between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. The dental instrument may further comprise a second actuating sensor in communication with the controller. The second actuating sensor may be configured to cause the metering valve to move between the first position in which fluid cannot flow from the source of fluid to the handpiece and the second position in which fluid flows freely from the source of fluid to the handpiece and between one or more intermediate positions where the fluid flows more or less freely thereby driving the handpiece at different speeds. The metering valve may provide intermediary speed between full-on and full-off by having as opposed to the use of an on-off valve. The metering valve may be driven by an analog signal produced any way by the actuation sensors. 
     One advantage of the use of the contact-less electromagnetic communication interface  95  is that all electrical components, including electrical wiring  75  and connections, are maintained within a closed volume of the handpiece  70  or the umbilical  73 . Therefore, there are no electrical contacts to corrode or erode and no protrusions or indentations that might potentially create crevices making disinfection and cleaning difficult. The distal face  84  of the handpiece  70  and the proximal face  88  of the umbilical  73  can be made of a smooth surface from the same material as the handpiece  70  or umbilical  73 . This simplifies the manufacturing process and makes the system more rugged and reliable. 
     The method used to communicate changes in the pressure sensor  72  parameter, which reflects the finger pressure applied by the physician, may be an alternating current probing the impedance of the sensing element of the pressure sensor  72 . More precise pressure sensors may be desired, and more precise pressure measurement can be achieved using a combination of sensing element and an analog front-end along with a signal processing and communication stage. In this case, the contact-less electromagnetic communication interface  95  can be used to supply electrical energy, which is then harvested and rectified to supply the circuits. Information is transferred back to the controller unit either by a protocol that “listens” to the sensor circuits, which at the appropriate time transmit information. Alternatively, the sensor circuit might use an impedance modulation of the load attached to the receiver coil and thereby communicate back to the controller circuits. 
     Turning now to  FIG. 21 , there is shown a dental handpiece  60  for dexterous operability with hand and foot actuation according to another example embodiment of the disclosure. A thin-film pressure sensor  62  is positioned on the dental handpiece  60 . Temporary retainer clips  64  on the handpiece  60  secure a first electrical wire  66  that is in electrical communication with the thin-film pressure sensor  62  and a splash-proof quick-disconnect  65 . Air tubing  67  is in fluid communication with a turbine unit  68 . Permanent retainer clips  69  secure to the air tubing  67  a second electrical wire  63  that is in electrical communication with the splash-proof quick-disconnect  65  and the control electronics  61 . The control electronics  61  provide electronic control of a pneumatic actuator inside turbine unit  68 . A wireless toe or heel sensor as in  FIG. 7  is in wireless communication with the control electronics  61 . The wireless communication may be using a secure wireless communication protocol such as IEEE 802.11 a/b/g/n using encryption for security and safety. 
     It is to be appreciated that according to any of the above-described embodiments of this disclosure, a number of features and/or advantages are present. First, dexterous or foot control is fully incorporated in the described handpiece designs. Second, the clip-on attachment(s) described to be placed on the handpiece are sterile and the handpiece can be sterilized. Additionally, isolated-stand-alone control circuits incorporating layered analog/digital logic can be implemented. Additional electronic logic circuitry may be implemented to avoid accidental operation of the handpiece. The operation of the handpiece can be achieved through pressure switch (via the user&#39;s hand) or a foot switch (via foot activation via a foot-sock), or both. The operation of the handpiece can also be achieved through pressure sensors (via the user&#39;s hand) or a foot sensor (via foot activation via a foot-sock), or both. These sensors can be configured to generate an analog signal that is transmitted wired or wirelessly to the controller, which then transmits an appropriate signal to a proportional actuator, such as a valve with controllable orifice, for example a needle valve. In this configuration the practitioner may control certain operating parameters of the handpiece proportionally to the finger or toe or heel pressure exerted. 
     Thus, the disclosure provides a dental handpiece for dexterous operability with hand and foot actuation. 
     Although the disclosure has been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the present disclosure can be practiced by other than the described embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the scope of the appended claims should not be limited to the description of the embodiments contained herein.