The present invention relates to a toothbrush.

Toothbrushes which have been used in the past have traditionally comprised a generally straight handle which is provided with a brush head at one end where the brush head supports a set of bristles which define a brushing face and in which the brushing face is generally planar. Over the years, the design of toothbrushes have been refined to provide handles which are anatomically designed such that when brushing teeth from a "forward position, the brush head is in general alignment with the buccal and lingual surfaces of posterior teeth. However, a principal difficulty with such toothbrushes resides in the substantially planar configuration of the brushing face which, without a substantial distortion of the bristles, prevents intimate contact of the brustrheads with the arcuate surface of the tooth and in particular witrrthe cavities which exist in the profile of teeth, particularly in the regions of the inclines whictrexist in the side faces of the teeth and the embrasures or spillways which are provided between adjacent teeth.

It is an object of this invention to provide a tuothbiusli which in use, is able to make intimate contact with the surfaces of at least some of the teeth without a severe distortion of the bristles. This is achieved in y neial terms by providing a brush head having the bristles provide a brushing face which is concave and has a generally anatomically complementary surface to the several convex surfaces that are characteristic ofihe primary and μemiai writ human teeth.

Accordingly, the inventiorττesides in a tυultibiush having a head supported from one end of the handle, said head -supporting a set of bristles extendiny fium one side of the head in closely spaced i elation whereby the outer ends of the bristles jointly provide a brushing face, said brushing face being concave in profile along both the longitudinal axes of the brushing face and the transverse axes of the brushing face between the ends of the brushing face to provide a recessed surface.

According to a preferred feature ofthe invention, said brushing face comprises two zones located along the longitudinal axis wherein each zone is provided with said recessed surface and the zones are separated by an intermediate raised portion. The raised portion is generally the same height as each end of the brushing face. It is a furtherpreferred that tli zunes are of a generally circular or ellipsoidal corifiguration in plan.

According to one particular embodiment of the invention the toothbrush is intended for the cleaning of primary teeth of infants and young children. The principal difficulty with prior ait toothbrushes which has been referred to above relates to the substantially planar configuration of the brushing face which is particularly inappropriate for use in the cleaning the primary teeth of infants and children which have a bulbous cervical ridge area on the buccat surfaces of the molar teeth.

It is an object of one embodiment of the invention to provide a toothbrush which in use is able to make intimate contact with the surfaces Ihe μrimaiy teeth without a severe distortion ofthe bristles. This is achieved in general terms by providing a brushhead having the bristles-provide a blushing face which is concave and has a generally anatomically complementar surface to the several convex surfaces that are characteristic ofthe primary human teeth.

Accordingly, the embodiment ofihe invention resides in a toothbrush having a head supported from one end ofthe handle, said head supporting a set of bristles extending from one side ofthe head in closely spaced relation whereby the outer ends of the bristles jointly provide a brushing face, said brushing face being concave in profile alony ϋuth the tuπyiludiπal axes of the brushing face and the transverse axes ofthe blushing face between ttie ends of the brushing face to provide a recessed surface, said recessed surface beiπy circular in plan.

According to a preferred ^{^} feature of the previous embodiment invention the recessed surface is of a part spherical shape.

According to a further preferred feature of the embodiment, said brushing face comprises two zones located along the longitudinal axis wherein each zone is provided with said recessed surface and the zones are separated by an intermediate raised portion. The raised portion is generally the same height as each end of the brushing face.

According to a further preferred feature ofthe invention the free- ends of the outer bristles in the region of outer periphery ofthe brushing face are directed radially inwardly with respect to the brushing face. In one embodiment of the invention this is effected by shaping the outer bristles such that they are curved. As an alternative the outer bristles are of a linear configuration and are mounted to the head such that they are directed radially with respect to the brushing face.

The invention will be more fully understood in the light ofthe following description of several specific embodiments. The description is made with reference to the accompanying drawings of which:

Figure 1 is a side-elevation of the head of the toothbrush according to the first embodiment;

Figure 2 is an end elevation of the brush head according to the first embodiment;

Figure 3 is a plan view of the brush head according to the first embodiment;

Figure 4 is a cross-sectional view of the brush head along line 4-4 of Figure 1 ;

Figure 5 is a sectional view of the brush head along line 5-5 of Figure 1 ;

Figure 6 is a sectional view along line 6-6 of Figure 2;

Figure 7 is a schematic view of a brush head acαjiϋiπy to the first embodiment in use in brushing both the buccai and lingual surfaces of the posteriorteeth of a set σfteeth in the lower jaw;

Figure 8 is a schematic side -elevation of a brush head according to the first embodiment in use in cleaning the upper surfaces of the teeth shown in Figure 7; and

Figure 9 is a cross-section of a tooth and brush head along line 9-9 of Figure 8.

Figure 10 is a plan view of the toothbrush and teeth shown at Figure 8.

Figure 11 is a side elevation ofthe brushhead of a toothbrush according to the second embodiment;

Figure 12 is a plan view of the brushhead according to the second embodiment;

Figure 13 is a cross-sectional view of the brushhead along line 13-13 of Figure 12;

Figure 14 is a schematic view of a brushhead according to the second embodiment in use in brushing both the buccat and lingual surfaces of the posterior teeth of a set of teeth inihe lower jaw;

Figure 15 is a schematic side elevation of a brushhead according to the second embodiment in use in cleaning the upper surfaces of the teeth shown in Figure 14; and

Figure 16 comprises a front elevation of a molar tooth and brushhead according to the second embodiment illustrating the contact of the toothbrush with the buccal (B) and lingual (L) surfaces of the primary molars.

Figure 17 is a plan view of the toothbrush and teeth shown at Figure 15.

Figure 18 is a sectional side view of a toothbrush according to the third embodiment.

Figure 19 is a plan view ofthe tϋϋtlibiush of Figure 18.

Throughout the following description of several embodiments of the invention the same reference numerals are used in respect of corresponding elements or components.

The first embodiment-shown at Figures 1 to 10 is directed to a toothbrush which is of an anatomical design such that it is able to more intimately contact both the buccal and lingual surfaces ofthe posteriorteeth.

The first embodiment comprises a brush head 11 which is supported from one end of a handle 12. The handle ofthe first embodiment is contoured such that when the posterior teeth are being brushed from a forward position (ie. with the handle projecting forwardly from the mouth), the brush head is substantially parallel to the line of the teeth as shown at Figure 7.

The brush head 11 supports a set of closely spaced bristles 13 which are mounted to the head in a conventional manner such-thatthey project from the face ofthe head which is intended to be located adjacent the teeth. The bristles 13 are arranged in two-zones 15 and 16 which are located end to end along the longitudinal axis of the brush such that they are contiguous with each other to define an intermediate portion 17. The outer ends of the bristles 13 define the brushing surface of the toothbrush. The lengths ofthe bristles are such that each zone 15 and 16 of the brushing face has a generally recessed configuration. The recessed configuration of the bristles is such that between each end and the intermediate portion 17, the brushing face is transversely concave as shown at Figure 4 and between each end ofthe inlei mediate portions 17, the brush head is longitudinally concave as shown at Figure 6. The degree of concavity which is defined between the ends of each zone and the intermediate portions 17 is such, that the recessed surface so provided, substantially conforms with the curved profile of the posteriorteeth both in the fore and aft axis of the mouth but also between the gingival margin and the crown ofthe teeth.

As a result of the configuration of the brushing face which is provided by the recessed portions of the zones 15 and 16 and ttie intermediate portion 17 and as shown at Figures 7, 8, 9 and 10 the brushing face is able to engage a pair of

adjacent teeth and is able to accommodate to the surface of the teeth without a substantial distortion of the bristles and undue pressure and abrasion being applied to portions ofthe teeth. In addition, as a result of such engagement, the ends of the zones 15 and 16 and the intermediate portion 17 of the brushing face are able to be received in the occiusal and incisal embrasures or spillways between the sides of the teeth, the embrasures between the crowns of the teeth, the cusp inclines in the crowns of the teeth and the central fissure in the teeth. With the brushing head located on the teeth as shown in figures 7, 8 and 9 and with application of a circular motionto he brush head according to conventional practice the surface of a pair of adjacent teeth can be contacted substantially completely by the brushing face to effect the cleaning of the entire surface of the teeth including the inclines and spillways. By indexing the position of the tooth brush past the buccal, lingual and upper surfaces ofthe posterior teeth, almost the entire surface ofthe poster iυi teeth can be adequately cleaned including the embrasures or spillways which exist between adjacent teeth and the cuspal inclines of the teeth. The brusrr head presents an anatomically complementary configuration to the various curved surfaces ofthe teeth and in particular can be readily received in locations where food particles can lodge to facilitate cleaning of such areas.

In addition if desired the bristles located in the region ofthe outerperiphery of the brushing face can be configured such that their free ends are directed substantially radially towardsihe brushing surface 16.

The configuration of the brushing face and the contoured configuration of the handle 12 ensures that the toothbrush when used appropriately can simulate the cleaning action which inthe past has only been possible by visiting the dentist for dental prophylaxis utilising cleaπingi>rushes.

The second embodiment shown ^t Figures 11 to 17 is directed to a toothbrush which is of an anatomical design such that it is able to more intimately contact both the buccal and lingual surfaces ofthe posterior primary teeth.

The second embodiment comprises a brushhead 11 which is supported from one end of a handle 12. The handle of the second embodiment is contoured such that when the posterior teeth aie being brushed from a forward position (ie. with the handle projecting forwardly fium the mouth), the brushhead is substantially parallel to the line of the teeth as shown at Figure 17.

The brushhead 11 supports a set of closely spaced bristles 13 which are mounted to the head in a conventional manner such that they project from the face of the handle which is intended to be located adjacent the teeth. The bristles 13 are arranged to define a circular array. The outer ends of the bristles 13 define the brushing surface 15 of the toothbrush. The lengths of the bristles is such that the brushing face has a generally recessed configuration which is such that, the brushing face 15 defines a generally part spherical concave surface. The degree of concavity is such- that the brushing iace conforms substantially with the curved profile of the posteriorteeth both in the fore and aft axis of the mouth but also between the gingival margin and the crown ofthe teeth and in particular with the bulbous curved ridges on the buccal surfaces of the primary molars.

In addition as shown at Figure 13 the outer bristles 17 located πrthe region of the outer periphery of the brushirrg-face-are configured such that their free-ends are directed substantially radially towardsthe brushing surface 16.

As a result of the configuration ofthe brushing face 15 and as shown at Figures 14, 15, 16 and 17 the brushing face is able to engage apair of adjacent teeth and is able to accommodate to the surface of the teeth without a substantial distortion of the bristles and without undue pressure and abrasion being applied to some portions of the surface of the teeth. In addition, as a result of such engagement, the edges of the brushing face are-able to be received in the αcctusal and incisal embrasures or spillways-betweerrthe sides ofthe teeth, the embrasures between the crowns of the teeth, the cusp inclines in the crowns of the teeth and the central fissure in the teeth.

With the brushing head located on the- teeth as shown in figures 14, 15, 16 and 17 and with application of a circular motion to the brushhead according to conventional practice the surface of a tooth can be contacted substantially completely by the brushing face with a substantially even pressure to effect the cleaning of the entire surface ofthe teeth including the inclines and spillways. By indexing the position of the tooth brush past the buccal, lingual and upper surfaces of the posteriorteeth, almost the entire surface ofthe posterior teeth can be adequately cleaned including the embrasures or spillways which exist between adjacent teeth and the cuspal inclines of the teeth. The brushhead presents an anatomically complementary configuration to the various curved surfaces of the teeth and in particular can be readily received in locations where food particles can lodge and dental plaque accumulates to facilitate cleaning of such areas. The configuration of the brushing face and the contoured configuration of the handle 12 ensures that the toothbrush when used appropriately can simulate the cleaning action which in the past has only been possible by visiting the dentist for dental prophylaxis utilising rotating cleaning brushes mounted in a motor-driven handpiece.

Figures 18 and 19 illustrate a third embodiment of this invention which has a brushhead with two sets of bristles 13 which are-each of a similarform to one set of bristles of the second embodiment and which are arranged such that the are positioned side by side along the longitudinal axis ofthe handle and such that they are closely adjacent to be contiguous to define a brushing face 15 having two recessed portions of the same form as the brushing face of the first embodiment separated by a raised intermediate portion 17. This third embodiment would be suitable for children with a mixed dentition of primary and permanent teeth.

It should be appreciated that the scope of the present invention need not be limited to the particular scope of the-embodimeπts described above.