Abstract:
The present invention is directed to a toothbrush ( 100 ) that incorporates tapered bristle filaments ( 141 ) in combination with tuft holes ( 142 ) of a reduced size, such as between 1.3 mm to 1.4 mm in diameter. In another aspect, the invention provides a toothbrush ( 100 ) that balances the number of tuft holes ( 142 ) and the number (X) of tapered bristle filaments ( 141 ) within each tuft hole ( 142 ) to achieve a unique ratio that reduces the cost of manufacture of the toothbrush ( 100 ) while maintaining a mouth-feel that consumers associate with a quality product. In still another aspect, the present invention provides a toothbrush ( 100 ) that incorporates tapered bristle filaments ( 141 ) and also achieves a balance between the perimeter of reduced size tuft holes ( 142 ) and the spacing between adjacent tuft holes ( 142 ) to achieve a unique ratio that reduces the cost of manufacture of the toothbrush ( 100 ) while maintaining a mouth-feel that consumers associate with a quality product.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     The present application is a U.S. national stage entry under 35 U.S.C. §371 of Patent Cooperation Treaty Patent Application No. PCT/CN2011/001555, filed Sep. 14, 2011, the entirety of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates generally to toothbrushes, and specifically to toothbrushes having bristle tufts formed by tapered bristle filaments. 
     BACKGROUND OF THE INVENTION 
     Toothbrushes using tapered bristle filaments (also referred to as tapered bristles or needle bristles) are known in the art. Tapered bristle filaments are bristle filaments in which at least the tip portions (i.e., the terminal end portions) of the bristle filaments have a tapered cross-section. The base portions of the tapered bristle filaments may have a generally cylindrical shape or may also have a tapered cross-section as desired. 
     The use of tapered bristle filaments in toothbrushes has become increasingly popular due at least in part to the unique “mouth-feel” and excellent cleaning performance provided by the very fine tapered tip portions. However, tapered bristle filaments require additional processing steps as compared to traditional non-tapered bristle filaments. Thus, tapered bristle filaments are quite a bit more expensive than non-tapered bristle filaments. 
     Therefore, there is a need for a toothbrush design that helps offset the increased cost of using tapered bristle filaments while maintaining its cleaning efficacy, unique mouth-feel, and perception of a quality product to the consumer. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention, in one aspect, provides a toothbrush that incorporates tapered bristle filaments in combination with tuft holes of a reduced size. In another aspect, the invention provides a toothbrush that balances the number of tuft holes and the number of tapered bristle filaments within each tuft hole to achieve a unique ratio that reduces the cost of manufacture of the toothbrush while maintaining a mouth-feel that consumers associate with a quality product. In still another aspect, the present invention provides a toothbrush that incorporates tapered bristle filaments and also achieves a balance between the diameter of reduced size tuft holes and the spacing between adjacent tuft holes to achieve a unique ratio that reduces the cost of manufacture of the toothbrush while maintaining a mouth-feel that consumers associate with a quality product. 
     In one embodiment, the present invention is directed to a toothbrush comprising: a handle; a head having a first surface comprising a plurality of tuft holes having a diameter D TH , wherein D TH  is in a range of 1.3 mm to 1.4 mm; and a bristle tuft mounted within and extending from each of the tuft holes, each of the bristle tufts formed by a plurality of tapered bristle filaments. 
     In another embodiment, the present invention is directed to a toothbrush comprising: a handle; a head having a first surface having X number of tuft holes; a bristle tuft mounted within and extending from each of the tuft holes, each of the bristle tufts formed by Y number of tapered bristle filaments; and wherein a ratio of X to Y is in a range between 1.05 to 1.64. 
     In yet another embodiment, the present invention is directed to a toothbrush comprising: a handle; a head having a first surface having a row of tuft holes, each of the tuft holes having a perimeter P; a bristle tuft mounted within and extending from each of the tuft holes, each of the bristle tufts formed by a plurality of tapered bristle filaments; wherein adjacent tuft holes in the row of tuft holes are separated by a distance Z, wherein Z is a linear distance between center points of the adjacent tuft holes; and wherein a ratio of Z to P is in a range of 0.35 to 0.46. 
     In an even further aspect, the invention can be a toothbrush comprising: a handle; a head having a first surface and a second surface, the first surface comprising a tufting area A TS  comprising X number of tuft holes, each of the tuft holes having a tuft hole area A TH ; a bristle tuft mounted within and extending from each of the tuft holes, each of the bristle tufts formed by a plurality of tapered bristle filaments; and wherein a ratio of A TS  to X×A TH  is in a range of 3.4 to 4.4. 
     In a still further aspect, the invention can be a toothbrush comprising: a handle; a head having a first surface and a second surface, the first surface comprising a tufting area A TS  comprising X number of tuft holes; a bristle tuft mounted within and extending from each of the tuft holes, each of the bristle tufts formed by a plurality of tapered bristle filaments; and wherein a ratio of A TS  to X is in a range of 5.0 to 6.5. 
     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 present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a side planar view of a toothbrush according to an embodiment of the present invention; 
         FIG. 2  is a front planar view of the toothbrush of  FIG. 1 ; 
         FIG. 3  is a close-up view of area III of  FIG. 2 ; 
         FIG. 4  is a longitudinal cross-sectional view taken along line IV-IV of  FIG. 2 ; 
         FIG. 5  is a front planar view of a toothbrush according another embodiment of the present invention; and 
         FIG. 6  is a close-up view of area VI of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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,” “top” and “bottom” as well as derivative 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. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto. 
     Referring to  FIG. 1 , a toothbrush  100  is illustrated. The toothbrush  100  extends from a proximal end  101  to a distal end  102  along a longitudinal axis A-A. The toothbrush  100  comprises a handle  110  and a head  120 . The handle  110  is an elongated structure that provides a user of the toothbrush  100  with a mechanism by which he/she can readily grip and manipulate the toothbrush  100 . The handle  110  may be formed of many different shapes, sizes, materials and by a variety of manufacturing methods that are well-known to those skilled in the art. If desired, the handle  110  may include a suitable textured grip made of a soft elastomeric material to enhance the handling of the toothbrush  100 . Although not illustrated, in certain embodiments the handle  110  may transition into a neck, which may be a portion of the toothbrush  100  with a smaller transverse cross-sectional area than the handle  110 . However, in other embodiments the handle  110  may transition directly into the head  120 . 
     In the exemplified embodiment, the toothbrush  100  is illustrated as a manual toothbrush. However, the invention is not to be so limited and in certain other embodiments the toothbrush can be a powered or electric toothbrush. 
     The handle  110  and the head  120  of the toothbrush  100  are formed as a single unitary structure using a molding, milling, machining or other suitable process. However, in other embodiments, the handle  110  and the head  120  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. Whether the head  120  and handle  110  are of a unitary or multi-piece construction (including connection techniques) is not limiting of the present invention, unless specifically stated. In some embodiments of the invention, the head  120  may be detachable (and replaceable) from the handle  110  using techniques known in the art. 
     The head  120  generally comprises a front surface  121 , a rear surface  122  opposite the front surface  121  and a peripheral side surface  123  that extends between the front and rear surfaces  121 ,  122 . The front surface  121  and the rear surface  122  of the head  120  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  121 ,  122  can be planar, contoured or combinations thereof. Moreover, if desired, the rear surface  122  may also comprise additional structures for oral cleaning or tooth engagement, such as a soft tissue cleaner or a tooth polishing structure. An example of a soft tissue cleaner is an elastomeric pad comprising a plurality of nubs and/or ridges. An example of a tooth polishing structure can be an elastomeric element, such as a prophy cup(s) or elastomeric wipers. Furthermore, while the head  120  is normally widened relative to the handle  110  (and the neck where applicable), it could in some constructions simply be a continuous extension or narrowing of the handle  110 . 
     Referring to  FIGS. 1 and 2  concurrently, the front surface  121  of the head  120  comprises a bristle field  140 , extending therefrom for cleaning teeth. While the bristle field  140  is particularly suited for brushing teeth, the bristle field  140  can also be used to clean other oral surfaces as desired. The bristle field  140  comprises a plurality of bristle tufts  146 , which in turn comprises a plurality of tapered bristle filaments  141 , mounted within tuft holes  142  of the head  120  and extend from the front surface  121  of the head  120 . 
     The front surface  121  of the head  120  of the toothbrush  100  comprises a tufting area A TS  in which a plurality of the tuft holes  142  are provided. In one embodiment, the tufting area A TS  is a substantially planar surface that is delimited by a contoured peripheral edge of the head  120 . In other embodiments, the tufting area A TS  may comprise one or more contours, either concave and/or convex. In the exemplified embodiment, the tufting area A TS  is oval in shape but can take on other shapes if desired. In certain embodiments, the tufting area A TS  is in a range of 180 to 270 mm 2 . In one preferred embodiment where the toothbrush  100  has a large head  120 , the tufting area A TS  is in a range of 210 mm 2  to 270 mm 2  in size. In a further preferred embodiment having a large head  120 , the tufting area A TS  is in a range of 230 mm 2  to 250 mm 2 , with a size of approximately 242 mm 2  being most preferred. In one preferred embodiment where the toothbrush  100  has a small head  120 , the tufting area A TS  is in a range of 180 mm 2  to 210 mm 2  in size. In a further preferred embodiment having a small head  120 , the tufting area A TS  is in a range of 190 mm 2  to 200 mm 2 , with a size of approximately 195 mm 2  being most preferred. 
     The tufting area A TS  of the front surface  121  of the head  120  comprises X number of the tuft holes  142 . In the exemplified embodiment, the number X of tuft holes  142  on the head  120  is equal to 44. However, the invention is not to be so limited and the number X of tuft holes  142  in the front surface  121  of the head  120  can range from 36 to 44 in other embodiments. More specifically, in an embodiment where the toothbrush  100  has a large head  120 , X is equal to approximately 44 and in an embodiment where the toothbrush  100  has a small head  120 , X is equal to approximately 36. Each of the tuft holes  142  comprises a diameter D TH  that is in a range of 1.3 mm to 1.4 mm. 
     In one embodiment, the diameter D TH  is selected so each tuft hole  142  has a tuft hole area A TH1  in a range of 1.30 mm 2  to 1.55 mm 2 . In certain other embodiments, the tuft hole area A TH1  and the number X of the tuft holes  142  are selected so that the ratio of A TS  to X×A TH1  is in a range of 3.4 to 4.4, and most preferably in a range of 3.52 to 3.57. As used herein, all ratios are given as an empirical number and, thus, are given with respect to 1. For example a ratio of 2 is, in fact, a ratio of 2:1. 
     Furthermore, a ratio of the tufting area A TS  to the number of holes X is in a range of 5.2 to 6.4. In one preferred embodiment wherein the tuft holes  142  have a circular or rounded shape, the ratio of the tufting area A TS  to the number of holes X is in a range of 5.3 to 5.6, and more particularly in a range of approximately 5.4 to 5.5. 
     The tuft holes  142  are arranged on the front surface  121  of the head  120  in rows. The rows of the tuft holes  142  include transverse rows  147  that extend substantially perpendicular to the longitudinal axis A-A and longitudinal rows  148  that extend substantially parallel to the longitudinal axis A-A. However, a number of the tuft holes  142  that are positioned nearest to the distal end  102  of the head  120  and a number of the tuft holes  142  that are positioned nearest a proximal end  125  of the head  120  are not in longitudinal alignment with the longitudinal rows  148  located in a central area of the head  120 . Furthermore, although the exemplary embodiment includes a plurality of transverse rows  147  and a plurality of longitudinal rows  148 , in certain embodiments, only a single transverse row  147  and/or longitudinal row  148  may be utilized. Similarly, in certain embodiments, the tuft holes  142  that are positioned nearest to the distal end  102  of the head  120  and the tuft holes  142  that are positioned nearest a proximal end  125  may be in longitudinal alignment with the longitudinal rows  148  located in a central area of the head  120 . 
     In the exemplified embodiment, a central section of the tuft holes  142  are arranged on the front surface  121  of the head  120  in a 9×4 array. Furthermore, there is an additional transverse row of three tuft holes  142  positioned below the 9×4 array nearest the proximal end of the head  120 , an additional transverse row of three tuft holes  142  positioned above the 9×4 array and an additional transverse row of two tuft holes  142  positioned at the distal end  102  of the head  120 . Of course, the invention is not to be limited by the particular arrangement of the tuft holes  142  illustrated and other arrangements of the tuft holes  142  on the front surface  121  of the head  120  are contemplated within the scope of the present invention. 
     Referring to  FIGS. 1 and 4  concurrently, the tapered bristle filaments  141  will be described in more detail. Each of the tapered bristle filaments  141  comprises a base portion  143  and a tapered portion  144 . Furthermore, each of the tapered bristle filaments  141  can be formed of a wide variety of materials suitable for forming filaments for oral use, including without limitation, polybutylene terephthalate, polyethylene terephthalate, nylon or the like. The tapered portions  144  of the tapered bristle filaments  141  can be formed by means of chemical etching by applying, for example, sulfuric acid or sodium hydroxide solution to the tapered portion  144  of the tapered bristle filaments  141  via an immersion or spray technique. During such a process, the chemical erodes away portions of the tapered bristle filaments  141  to form the tapered portion  144 . Alternatively, the tapered portions  144  of the tapered bristle filaments  141  may be tapered by mechanical means, including shaving the bristle ends with the blade of a knife, grinding, or with a rounding machine or by any other means. Whether chemical or mechanical means are used to form the desired taper, the tapering results in a bristle having a generally conical or truncated-cone profile that tapers towards its terminal end. 
     In the exemplified embodiment, the cylindrical base portion  143  of each of the tapered bristle filaments  141  extends approximately two-thirds the length of the tapered bristle filament  141  from the front surface  121  of the head  120  to a distal tip  145  of the tapered bristle filament  141 . Thus, in the exemplified embodiment each of the tapered bristle filaments  141  tapers to the distal tip  145  only in the top one-third portion of the tapered bristle filament  141 . However, in certain other embodiments the tapered portion  144  of the tapered bristle filament  141  may extend from approximately one-half of the length of the tapered bristle filament  141  from the front surface  121  of the head  120  to the distal tip  145  of the tapered bristle filament  141 . In such an embodiment, the tapered bristle filaments  141  begin to taper at approximately one-half the length. Furthermore, in still other embodiments each of the tapered bristle filaments  141  may taper throughout the entire length of the filament  141  including both the base and tapered portions  143 ,  144 . In still other embodiments, the tapered portion  144  may be less than one-third of the entire length of the filament  141 . Thus, the invention is not to be limited by the relative length the base portion  143  and the tapered portion  144 . 
     Each of the tapered bristle filaments  141  has a diameter DB (referring to  FIG. 3 ) at the base portion  143  that is in a range of 0.16 mm to 0.19 mm. The diameter DB is the largest diameter of the tapered bristle filaments  141 . Thus, as the bristle filaments  141  taper towards the distal end  145 , the diameter of the tapered bristle filaments  141  decreases. 
     The bristle tufts  146  of the bristle field  140  of the present invention can be affixed to the head  120  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 bristle tufts  146  (which comprise the tapered bristle filaments  141 ) to the head  120 . 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 tapered free ends of the tapered bristle filaments  141  on one side of the plate or membrane perform the cleaning function. The non-tapered free ends of the tapered bristle filaments  141  on the other side of the plate or membrane are melted together by heat to be anchored in place. Alternatively, the bristles could be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles is mounted within or below the tuft block. 
     The term “bristle filament” is used herein to refer to each individual filament that extends upwardly from the front surface  121  of the head  120 . When the bristle tufts  146  are connected to the head via a traditional staple/anchor technique, the bristle tufts  146  (and thus each bristle strand that makes up the bristle tuft  146 ) are mounted within the tuft holes  142  in a bent manner so as to resemble a general U-shape. Thus, each single bristle strand (which is tapered at both ends) is bent in a U-shape and, as a result, forms two distinct tapered bristle filaments  141  extending upwardly from the front surface  121  of the head  120 . In other words, when using staples/anchors, a single bristle strand is bent in half and stapled to the head  121  such that two tapered bristle filaments  141  extend from the head  120 . Thus, the number of tapered bristle filaments  141  is twice the number of bristle strands. In order to ensure that each of the bristle filaments  141  has a taper at its distal end  145 , when anchors/staples are used to connect the tapered bristle filaments  141  to the head  120 , the bristle strands are tapered at both ends such that each end of the bristle strand is tapered. In this manner, each of the two bristle filaments  141  that extend from the head  120  as a result of a single bristle strand being affixed to the head  120  via anchors/staples will have a taper. 
     When using IMT of AFT for connecting the tooth engaging elements  140  to the head  120 , each individual bristle strand results in only a single tapered bristle filament  141 . Thus, in such an embodiment, each of the tapered bristle filaments  141  is tapered on only one end. Furthermore, in such embodiments the number of tapered bristle filaments actually extending from the front surface  121  of the head  120  is equal to the number of bristle strands actually affixed to the head  120 . 
     Referring to  FIGS. 1-4  concurrently, the toothbrush  100  of the present invention will be described in more detail. Mounted within each of the tuft holes  142  is a bristle tuft  146 . Each of the bristle tufts  146  is formed from a plurality of the tapered bristle filaments  141 . More specifically, each of the bristle tufts  146  comprises a number Y of tapered bristle filaments  141 . In the exemplified embodiment, each of the bristle tufts  146  comprises  34  of the tapered bristle filaments  141  (which, as described above, would be equal to 17 bristle strands when an anchor/staple technique is utilized). However, the invention is not to be so limited and the number Y of tapered bristle filaments  141  that form each bristle tuft  146  can be in a range from 28 to 40 (which would be equivalent to 14 to 20 bristle strands when an anchor/staple technique is used). Thus, the total number of tapered bristle filaments  141  on the toothbrush  100  is in a range from 1176 to 1840, and more specifically in a range from 1232 to 1760. When the tapered bristle filaments  141  are connected to the head via an IMT of AFT technique, the total number of bristle strands is equal to the total number of tapered bristle filaments  141 . However, when the tapered bristle filaments  141  are connected to the head via an anchor/staple technique such that a single bristle strand creates two distinct tapered bristle filaments  141 , the toothbrush  100  will comprise from 588 to 920 total bristle strands, and more specifically from 616 to 880 total bristle strands. 
     Furthermore, as discussed above, the tuft holes  142  are arranged on the first surface  121  of the head  120  in rows  147 ,  148 . Adjacent tuft holes  142  in each of the transverse rows  147  are separated by a distance Z TR1 . More specifically, each of the tuft holes  142  has a center point  149  and Z TR1  is a linear distance between the center points  149  of adjacent tuft holes  142  in the transverse rows  147 . Furthermore, adjacent tuft holes  142  in each of the longitudinal rows  148  are separated by a distance Z LR1 . More specifically, Z LR1  is a linear distance between the center points  149  of adjacent tuft holes  142  in the longitudinal rows  148 . In the exemplified embodiment, the distance Z TR1  is equal to the distance Z LR1 . However, in certain other embodiments the distance Z TR1  can be different than the distance Z LR1 . In embodiments where Z TR1  and Z LR1  are different, Z LR1  is greater than Z TR1 . Regardless of whether the distances Z TR1 , Z LR1  are equal or different, both the distance Z TR1  between adjacent tuft holes  142  in each of the transverse rows  147  and the distance Z LR1  between adjacent tuft holes  142  in each of the longitudinal rows are in a range of 2.1 mm to 2.4 mm. In one specific embodiment, the distance Z TR1  is in a range of 2.1 mm to 2.3 mm, with 2.2 mm being preferred, while the distance Z LR1  is in a range of 2.3 mm to 2.4 mm, with 2.32 mm being preferred. In another embodiment, the distance Z LR1  is preferably 2.3 mm. The tuft holes  142  also have a perimeter (or circumference) that is in a range of between 4.0 mm to 5.0 mm. 
     When circular tufts holes  142  are used, with the distance Z being in the range of 2.1 mm to 2.4 mm and the diameter D TH  of the tuft holes  142  being in the range of 1.3 mm to 1.4 mm, a ratio of Z to D TH  is preferably maintained in a range of 1.5 to 1.8. 
     Furthermore, as described above the number X of tuft holes  142  is in a range of 42 to 46 and the number Y of tapered bristle filaments  141  per tuft hole  142  is in a range of 28 to 40. Thus, a ratio of X to Y is in a range of 1.05 to 1.64, and more specifically the ratio of X to Y is approximately equal to 1.3. However, the invention is not to be so limited and the ratio of X to Y may fall outside of the above-noted range in certain embodiments. Nonetheless, the ratio of X to Y is greater than one in all embodiments. 
     The present invention uses the tuft holes  142  having a diameter D TH  in a range of 1.3 mm to 1.4 mm to increase the total number of the tuft holes  142  that will fit on the head by creating a pattern of the tuft holes  142  with a relatively small linear distance between the center points  149  of adjacent tuft holes  142 . By positioning the tuft holes  142  closely together on the head  110 , a reduction in the number of tapered bristle filaments  141  disposed within each tuft hole  142  can be achieved without reducing the overall appearance or affect of the toothbrush  100 . Table 1 provides a relative comparison between a conventional tuft hole layout and the tuft hole layout of the present invention. 
     
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 Number  
                 Total 
               
               
                   
                   
                   
                 Filaments 
                 of 
                 Number 
               
               
                   
                 Hole 
                 Bristle 
                 per 
                 Tuft 
                 of 
               
               
                   
                 Diameter 
                 Diameter 
                 hole 
                 Holes 
                 Filaments 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Conventional 
                 1.52 mm 
                 0.175 mm 
                 46-50 
                 40 
                 1840-2000 
               
               
                 Present  
                 1.40 mm 
                 0.175 mm 
                 28-40 
                 44 
                 1232-1760 
               
               
                 Invention 
                   
                   
                   
                   
                   
               
               
                   
               
             
          
         
       
     
     The data in Table 1 indicates an average strand reduction from 1920 in a conventional tuft layout, versus 1496 for the layout of the present invention described herein above, despite the increase in the number of tuft holes on the head. This represents a surprising 22% reduction in the amount of tapered bristle filaments on average per toothbrush. Such a reduction in the total number of tapered bristle filaments per toothbrush is significant due to the added costs involved in creating a tapered bristle filament. In addition, such a reduction in the amount of tapered bristle filaments provides improved deeper cleaning because less bristle filaments are fighting for the tight and hard-to-reach spaces between gums and teeth. Further, it is believed that the reduction in the amount of tapered bristle filaments leads to less waste of materials while maintaining similar performance, and in some instances achieving superior performance. 
     Referring now to  FIGS. 5 and 6 , a toothbrush  100 A according to another embodiment of the invention is illustrated. The toothbrush  100 A is identical to the toothbrush  100  in all respects except that the tuft holes  142 A in the toothbrush  100 A are rectangular, or square in shape rather than circular. Only those components of the toothbrush  100 A that are different from the components of the toothbrush  100  will be described in detail below. The same reference numerals are used herein and in the drawings to designate similar components, except that for the toothbrush  100 A there is an “A” at the end of each reference numeral. 
     The toothbrush  100 A comprises a tufting area A TS  having similar size requirements or preferences as the toothbrush  100 . Thus, the tufting area A TS  of the toothbrush  100 A is in a range of 210 mm 2  to 270 mm 2 . Moreover, in large head embodiments, the tufting area A TS  is in a range of 230 mm 2  to 250 mm 2 , with a size of approximately 242 mm 2  being most preferred. In small head embodiments, the tufting area A TS  is in a range of 180 mm 2  to 210 mm 2 , more preferably in a range of 190 mm 2  to 200 mm 2 , with a size of approximately 195 mm 2  being most preferred. 
     Also similar to the toothbrush  100 , the toothbrush  100 A comprises X number of tuft holes  142 A, wherein X is in a range of 32 to 40. More specifically, in an embodiment wherein the toothbrush  100 A has a small head  120 A, X is equal to approximately 32 and in an embodiment wherein the toothbrush  100 A has a large head  120 A, X is equal to approximately 40. As noted above, in the toothbrush  100 A the tuft holes  142 A are rectangular or square in shape having a side length L S  in a range of 1.2 mm to 1.6 mm, and more specifically approximately 1.4 mm. Thus, the tuft holes  142 A have a tuft hole area A TH2  in a range of about 1.7 mm 2  to 2.2 mm 2 , and more specifically approximately 1.96 mm 2 . 
     A ratio of the tufting area A TS  to the number of holes X is in a range of 5.2 to 6.4. In one preferred embodiment wherein the tuft holes  142  have a square or rectangular shape, the ratio of the tufting area A TS  to the number of holes X is in a range of 5.9 to 6.2, and more particularly in a range of approximately 6.0 to 6.1. 
     Similar to the toothbrush  100 , the tuft holes  142 A in the toothbrush  100 A are arranged on the first surface  121 A of the head  120 A in rows  147 A,  148 A. The rows  142 A in the toothbrush  100 A have the same configuration as the rows of tuft holes  142  in the toothbrush  100  except that the central section of tuft holes  142 A are arranged on the front surface  121 A of the head  120 A in an 8×4 array. The remainder of the tuft holes  142 A are arranged as discussed above with regard to the tuft holes  142  of the toothbrush  100 . Of course, the invention is not to be limited by the particular arrangement of the tuft holes  142 A illustrated and other arrangements of the tuft holes  142 A on the front surface  121 A of the head  120 A are contemplated within the scope of the present invention. 
     Adjacent tuft holes  142 A in each of the transverse rows  147 A are separated by a distance ZTR2. More specifically, each of the tuft holes  142 A has a center point  149 A and ZTR2 is a linear distance between the center points  149 A of adjacent tuft holes  142 A in the transverse rows  147 A. Furthermore, adjacent tuft holes  142 A in each of the longitudinal rows  148 A are separated by a distance ZLR2. More specifically, ZLR2 is a linear distance between the center portions  149 A of adjacent tuft holes  142 A in the longitudinal rows  148 A. In certain embodiments, the distance ZLR2 between adjacent tuft holes  142 A in each of the longitudinal rows are in a range of 2.1 mm to 2.3 mm, with 2.2 mm being preferred. Moreover, in certain embodiments the distance ZLR2 between adjacent tuft holes  142 A is in a range of 2.3 mm to 2.7 mm, with 2.55 mm being preferred. 
     In embodiments where the tuft holes  142 A are not circular in shape, the tuft holes  142 A will generically comprise a perimeter P. According to certain embodiments of the present invention, the perimeter P is selected to be in a range of 5.0 mm to 6.0 mm, and more preferably in a range of 5.4 mm to 5.8 mm, and most preferably approximately 5.6 mm. In certain other embodiments of the invention, the sizes of the tuft holes  142 A and the distances Z TR2 , Z LR2  (collectively referred to as “Z”) therebetween are controlled so that a ratio of Z to P is in a range of 0.35 to 0.46. In such embodiments, Z is preferably in a range of 2.1 to 2.7, and more preferably in a range of 2.2 mm to 2.6 mm. Of course, the embodiments having circular tuft holes  142  discussed above can have Z and P controlled such that the ratio of Z to P fits within the above-noted range. 
     In some embodiments, the tuft holes  142 ,  142 A will be neither circular nor rectangular/square. For example, the tuft holes may be diamond-shaped, triangular or oval in certain embodiments. 
     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 foregoing description and drawings represent the exemplary embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the present invention as defined in the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims, and not limited to the foregoing description or embodiments.