with reference to fig1 , fig2 , fig3 and fig4 , wherein like numerals represent like features , an exemplary double - sided toothbrush according to principles of the invention includes a handle 100 ( not fully shown ) and a head assembly 130 . the handle 100 may be any type of handle suitable for a toothbrush , including but not limited to straight , angled , flexible , ergonomic , ornamental or otherwise . the head assembly 130 includes a base 115 and bristles 110 , 120 attached thereto . the bristles 110 , 120 may be seated in the form of tufts in holes in the base and fastened by the ends inserted into the holes with anchors , adhesives or chemical or thermal bonds . groups of adjacent bristles form a brushing surface . bristles comprising a brushing surface may be the same size , of varying sizes , angled or straight relative to the base 115 . additionally , the bristles may be comprised of any materials suitable for toothbrush bristles . furthermore , the brushing surfaces may including scrubbing , cleansing or rubbing structures in addition to bristles . indeed , the brushing surfaces are intended to represent a broad category of toothbrush brushing surfaces suitable for use in cleaning teeth . the head assembly of the present invention includes two separate opposed brushing surfaces 125 , 105 — i . e ., a primary brushing surface 125 and a secondary brushing surface 105 . the primary brushing surface 125 includes primary bristles 120 used when brushing teeth . for convenience of reference , the side of the head assembly 130 having the primary bristles 120 is referred to herein as the front of the toothbrush head assembly 130 , and the opposite side is referred to as the back . the opposite side ( i . e ., back ) of the toothbrush head assembly 130 , features secondary bristles 110 comprising a secondary brushing surface 105 . in a preferred embodiment , the average height h 2 of the secondary bristles 110 is substantially less than the average height h 1 of the primary bristles 120 . in a particular preferred embodiment , the average height h 2 of the secondary bristles 110 is approximately 0 . 35 to 0 . 75 times the average height h 1 of the primary bristles 120 . illustratively , the primary bristles may be approximately 7 to 10 mm in length , while the secondary bristles may be approximately 3 to 7 mm in length . the length l of the primary 125 and secondary 105 brushing surfaces may either be the same or different . the width w of the brushing surfaces may vary depending upon the size of the toothbrush . a narrow brush may be provided for use by children , while a wider brush may be provided for adult use . exemplary widths range from 5 to 20 mm . having a primary brushing surface 125 and a secondary brushing surface 105 offers several advantages over conventional toothbrushes . one advantage is that a single toothbrush in accordance with principles of the invention may provide brushing surfaces of different hardness , stiffness , configuration and / or composition . by way of example and not limitation , the primary brushing surface 125 may provide a straight soft or medium brushing surface , while the secondary brushing surface 105 may provide a firm or hard brushing surface , with straight or angled bristles . a hard / firm brushing surface is particularly useful for cleaning stubborn stains and removing plaque buildup and food particles . a softer brushing surface or brushing surface with an alternative configuration ( e . g ., size , shape , contour , bristle density , arrangement or configuration ) may be preferable for routine brushing and caring of sensitive dental and oral surfaces . a lower bristle density provides fewer bristles per unit area . different materials may be utilized to provide different scrubbing , frictional and abrasive properties for the primary and secondary bristles . another advantage of having both a primary brushing surface 125 and a secondary brushing surface 105 is an ability to clean different oral surfaces simultaneously . the primary brushing surface 125 may be used to scrub bottom teeth while the secondary brushing surface 105 scrubs upper teeth , or vice versa . thus , the secondary brushing surface 105 provides a means for cleaning any oral or dental surfaces that are opposite the primary brushing surface 105 and within reach . yet another advantage of having both a primary brushing surface 125 and a secondary brushing surface 105 is an ability to provide various brushing surface configurations to facilitate cleaning hard to reach areas . for example , inwardly angled secondary brushing surfaces 305 , 310 , as shown in fig3 , may be provided to facilitate reaching behind teeth . alternatively , outwardly angled brushing surfaces 405 , 410 , or small surface area brushing surfaces 400 may be provided to clean hard to reach dental and oral areas , as shown in fig4 . thus , a user may effortlessly switch from a conventional brushing surface to a specialized brushing surface adapted for cleaning hard to reach areas , all without removing the brush from his or her mouth . an important aspect of a preferred embodiment of the present invention is a manageable size . specifically , the total height of the brush , including the heights h 1 , h 2 of both brushing surfaces 105 , 125 , plus the height of the base 115 is not too great to comfortably fit in one &# 39 ; s mouth . the reduced height h 2 of the secondary brushing surface 105 makes this possible . for many users , a brush head with a pair of opposed full - height brushing surfaces would be impossible or at least difficult to manage . advantageously , the relatively short secondary bristles 110 do not create too great an obstacle for brushing . in yet another aspect of an exemplary embodiment of the invention , the double - sided toothbrush may include an active substance functionally applied to the secondary ( and / or primary ) bristles 110 , 120 . the bristles may be coated or impregnated with the substance . the active substance may comprise an antibiotic , flavorant , anti - bacterial agent , medicant , coagulant , anti - inflammatory agent , fluoride compound , anticalculus agent , desensitizing agent , local anaesthetic agent and / or polishing agent . the side having the active ingredient may be used when needed . thus , for example , bristles having a desensitizing agent may be used when a sensitive area is contacted . at other times the other side may be used to avoid over - usage or unnecessary treatment . while the invention has been described in terms of various embodiments , implementations and examples , those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims including equivalents thereof . the foregoing is considered as illustrative only of the principles of the invention . variations and modifications may be affected within the scope and spirit of the invention .
a double - sided toothbrush includes bristles on opposite sides of the brushing head . primary bristles are provided for routine brushing . opposed secondary bristles are provided for additional or specialty brushings . the double - sided toothbrush with bristles on both sides may easily be positioned in the mouth for cleaning plaque and food particles from teeth , tongue , gums , cheek , roof of mouth , dental implants and braces .