This application claims priority of U.S. Patent Application Serial No. 12/634,788 filed December 10, 2009, the disclosure of which is incorporated herein by reference .

BACKGROUND

Disclosed herein are toothbrushes with a unique arrangement, sizing and configuration of bristles for enhancing the cleaning of the teeth and gums.

By nature, the surface of a tooth is uneven. The various crevices and other irregularities in a tooth surface present difficulties in cleaning the tooth with conventional toothbrushes. Cavity-causing food and plaque will find their way into these crevices and irregularities, and unless removed promptly and effectively, will eventually cause decay. Over 90% of cavities occur in the central fossa area of a tooth (the central region with ridges and grooves) where food and plaque build-up.

Similarly, the area between teeth is often difficult to reach with conventional toothbrushes, and therefore also serves as a haven for cavity-forming plaque unless removed promptly.

In addition, the toothbrush itself is a haven for bacteria; over 100 million microorganisms can exist on a single toothbrush head.

It therefore would be desirable to provide a toothbrush with bristles that effectively clean teeth and/or gums and remove plaque and other debris effectively, regardless of the surface contour of the tooth . It also would be desirable to reduce or eliminate bacteria residing on the toothbrush.

SUMMARY

The embodiments disclosed herein relate generally to toothbrushes, both manual and powered. In certain embodiments, the toothbrush comprises a plurality of dual or multi-action bristles which enable the cleaning between the teeth and on the surfaces of the teeth. In certain embodiments, certain of the bristles are longer than others, enabling them to reach into small but deep crevices on the surface of the tooth, and between teeth. In certain embodiments, longer bristles are provided that can effectively contact and stimulate the gums during the tooth brushing process. In certain embodiments, certain of the bristles are harder than others, enabling the effective cleaning of the tooth by removing stubborn debris that would remain were the bristles too soft.

In certain embodiments, reduction or elimination of bacteria residing on the toothbrush is achieved by incorporating in the bristles or filaments making up the bristles one or more antimicrobial agents, such as antibiotics. For example, antimicrobial metal ions, such as silver ions, are a powerful, natural antibiotic and preventative against infections. Acting cL S cL C3.talyst , they disable the enzyme that one-cell bacteria, viruses and fungi need for their oxygen metabolism. They suppress respiration and metabolism without corresponding harm occurring to human enzymes or parts of the human body chemistry. Silver also disrupts bacteria membranes, inter-membrane enzymes, and DNA transcription. The result is the destruction of disease-causing, odor- causing organisms on the device that could deleteriously affect the user. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a toothbrush in accordance with certain embodiments;

FIG. 2 is a perspective view of the head of the toothbrush of FIG. 1;

FIG. 3 is a perspective view of an array of bristles on the head of the toothbrush of FIG. 1;

FIG. 4 is a cross-sectional view of a tooth showing the inability of prior art bristles to reach crevices;

FIG. 5 is a cross-sectional view of a tooth showing the ability of bristles to reach cervices in accordance with certain embodiments;

FIG. 6 is a cross-sectional partial view of the interdental area between two teeth showing the ability of bristles to reach that area in accordance with certain embodiments ;

FIG. 7 is a another cross-sectional partial view of the interdental area between two teeth showing the ability of bristles to reach that area in accordance with certain embodiments;

FIG. 8 is yet another cross-sectional partial view of the interdental area between two teeth showing the ability of bristles to reach that area in accordance with certain embodiments;

FIG. 9 is a perspective view is the head of the toothbrush of FIG. 1;

FIG. 10 is a is a perspective view of an array of bristles on the head of the toothbrush of FIG. 9, with one such bristle highlighted; and

FIG. 11 is a perspective view of the highlighted bristle of FIG. 10 showing an attachment mechanism in accordance with certain embodiments. DETAILED DESCRIPTION

Turning first to FIGS. 1-3, there is shown generally at 10 a toothbrush having an elongated handle 11 and a head 12. The configuration of the handle 11 is not particular limited, although preferably it is ergonomic and contoured (e.g., it can include ribs for finger engagement and a recess for thumb placement) to facilitate engagement by the hand of the user, particularly in the manual toothbrush embodiment. The handle 11 can be shaped in a curvilinear fashion to facilitate access of the working end to the rear molars and other hard to reach places in the mouth. Preferably the handle 11 and head 12 form a monolithic integral structure. Suitable materials of construction of the handle 11 and head 12 include flexible thermoplastic polymers, such as polyurethane, PVC, rubber, and/or polylactic acid. A polyolefin, such as polypropylene, is preferred. Although preferably the handle 11 and head 1 are made of the same material, the embodiments disclosed herein are not so limited.

The head 12 provides a substrate from which the bristles extend, preferably vertically or orthogonally therefrom. Preferably the top surface of head 12 is flat. The particular top, cross-sectional shape of the head is not limited; it is generally oval in the embodiment shown, but other shapes, including irregular and regular shapes such as rectangles, circles polygons, etc. are within the scope of the embodiments disclosed herein. Heads with top cross-sectional circular shapes are particularly useful for power-operated (e.g., battery driven) toothbrushes.

In certain embodiments, a plurality of spaced arrays or clusters 15 of bristles are provided extending from the head 12, such as via the arrangements shown in FIGS. 1 and 2. Preferably the bristles 15 cover substantially the entire top surface of the head 12. For example, the outer perimeter of the head 12 can include 24 spaced arrays or clusters of bristles. A second set of 18 spaced arrays or clusters can be located radially inwardly of the outer perimeter of arrays, and a third set of 4-5 spaced arrays or cluster can be located radially inwardly of the second set. In certain embodiments the arrays or clusters 15 are equally spaced and are positioned symmetrically about the longitudinal centerline of the head 12. Those skilled in the art will appreciate that other configurations of the arrays or clusters are well within the spirit and scope of the embodiments disclosed herein. For example, in the case of a circularly shaped head 12, arrays can be positioned concentrically, with a first set having the greatest number of arrays (e.g. 16) positioned in a circular pattern along the outer circumferential perimeter of the head, a second set of fewer arrays (e.g., 8) positioned radially inwardly of the outer arrays, and a third set of still fewer (e.g., 4) arrays positioned radially inwardly of the second set. Suitable distances between spaced arrays 15 ranges from about 1.0 to 1.5mm.

FIG. 3 illustrates in greater detail one exemplary array or cluster 15 of bristles in accordance with certain embodiments. Within the array 15, a plurality of bristles 16 terminates in a relatively blunt, untapered end, and a plurality of bristles 17 terminates in a relatively sharp, tapered distal end. The tip gets as small as 1 micrometer at its free end; the widest portion is 0.20 millimeters. In certain embodiments, the portion of the bristles 16 extending axially from the head 12 is of a uniform or substantially uniform cross-section. In certain embodiments, the portion of each bristle 17 extending axially from the head 12 is of a uniform or substantially uniform cross-section except for the tapered distal end. In certain embodiments, the uniform or substantially uniform cross-section portion of each bristle 17 is of the same cross-section as the cross- section of the portion of each bristle 16 extending axially from the head 12. In certain embodiments, the uniform or substantially uniform cross-section portion of the bristles 16 and 17 is about 0.18mm in diameter. In certain embodiments, the diameter of the top tapered portion is about 1 micrometer. The tapered bristles 17 extend axially or vertically higher than the blunt bristles 16, as shown. In certain embodiments, the bristles 16 extend a distance of from about 8-9 mm from the surface of the head 12, and the bristles 17 extend a distance of from about 12-13 mm from the surface of the head 12. In certain embodiments, the bristles 16 extend from the surface of the head 12 about 2/3 the distance as the bristles 17.

As was the case with the number of arrays 15, the number of bristles in a given array 15 is not particularly limited. Also, the particular location of the longer bristles 17 relative to the shorter bristles 16 also is not particularly limited, although it is preferred that the longer bristles 17 are positioned at or near the outer edges of each array so that they are available for accessing the area between teeth and thus act as a flossing element. An exemplary toothbrush sized for an adult may have 2116 total bristles, whereas one sized for a child may have 1288 total bristles.

The bristles 16 and 17 may be made of natural or synthetic materials typically suitable for brushing teeth. Preferred materials include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) , with the latter being particularly preferred. PBT is more durable than nylon and has about 24% better bending recovery and 95% better crimp rigidity.

Turning now to FIGS. 9-11, there is shown the preferred bristle configuration and method of securing the same in the toothbrush head 12. As can best be seen in FIGS. 10 and 11, a single filament 20 is used to create both the shorter, blunt bristle 16 and the longer, tapered bristle 17. The single filament 20 is bent, at a suitable location 21 along its length, so as to ensure that the tapered distal end 27 extends from the bent location 21 a distance farther than the blunt, rounded end 28. This bent location 21 is positioned under the top surface of the head 12 and is secured by any suitable means, such as by gluing, molding and curing the head about the filaments, or preferably by fastening to the head material with a staple 25 or the like positioned as shown, e.g., looping the filament around the staple 25. Accordingly, no bristle end is attached to or embedded in the head. A single staple can be used to fasten all the filaments within an array 15.

Accordingly, the bristle arrangement is preferably formed not by embedding respective ends of the filaments in the head 12 of the toothbrush, but rather by embedding, affixing or otherwise securing an intermediate portion of each filament in the head 12. This provides greater flexibility in altering the height of each bristle extending from the head 12; modifying the location of the bent portion 21 alters the relative heights of bristles 16 and 17 without altering the total length of a filament or having to provide filaments of different lengths. Concomitant with this flexibility, additional flexibility can be achieved by also using filaments of different overall length to create a multi- tiered bristle device.

Regardless of whether the different heights to which the bristles extending from the surface of the head 12 are created by the relative location of the bent portion 21, the use of filaments of different overall lengths, or both, the bristles of different heights can be arranged in any pattern on the surface of the head 12. Thus, different heights within an individual array 15 can be achieved, as shown in FIG. 10, or the heights within a given arrays can be the same, but among arrays can be different, or both. Although multi-tiered arrays having bristles of two distinct heights (bristles 16 and bristles 17) are illustrated, arrays with bristles of three or more distinct heights are within the scope of the embodiments disclosed herein.

The multi-action achieved by the various-sized bristles allows for excellent cleaning or flossing between teeth (e.g., with longer, tapered bristles 17), as well as complete cleaning of the tooth itself (e.g., with the shorter, thicker bristles 16) . For example, as seen in FIGS. 5-8, some of the longer bristles 17 (e.g., those positioned along the outer perimeter of an array) extend beyond the top surface of the tooth to clean or polish the sides of the tooth 50 (FIG. 5), and some of the longer bristles 17 reach into the small crevices on the surface of the tooth 50. Similarly, some of the longer bristles 17 extend into the interdental area or the area between teeth (FIGS. 8 and 9) and function to remove debris located there.

In certain embodiments, antimicrobial activity can be imparted to the bristles to help reduce or eliminate bacteria that flourish both on a toothbrush and in the mouth. Preferably this is carried out by impregnating the filaments with antimicrobial metal ions such as zinc, copper, gold, and/or silver, preferably silver, most preferably nano-silver (particles ranging in size from about 1 to about 50 nm) . This can be carried out, for example, in accordance with the methods disclosed in JP 2005-358184, the disclosure of which is hereby incorporated by reference. Thus, the PBT resin used to form the filaments can be mixed with a silicon compound or silicon compound derivative including the metal ions prior to forming, such as by extrusion, the filaments into their desired length. Impregnating the filaments with the nano-particles helps ensure that the silver remains on the bristles longer, compared to simply dipping or otherwise coating the bristles with silver. Preferably the bristles contain about 150 ppm of silver, which has is effective in killing about 99.9% of bacteria resident thereon in 6 hours (ASTM standard tests using Klebsiella Pneumoniae bacteria showed 99.7% reduction in 1 hour and 99.9% reduction in 6 hours) . In certain embodiments, the antimicrobial agent commercially available as MICROBAN ^® can be used.