CA2261763A1 - Toothbrush with improved cleaning and abrasion efficiency - Google Patents

Abstract

A toothbrush having a plurality of bristles (12) of synthetic thermoplastic polymeric composition. The bristles (12) having a plurality of channels (13) therein extending along the length thereof. The channels (13) having a depth sufficient to entrap a quantity of toothpaste abrasive, wherein the cleaning and abrasion contact between the quantity of abrasive entrapped in the channels (13) and the surfaces of the teeth is improved during brushing.

Description

wo 98/04167 PCT/US97/12206 TOOTHBRUSH WlTH IMPROVED CLEANING
AND ABRASION EFFICIENCY

FIELD OF THE INVENTION

A toothbrush having an improved cleaning and abrasion efficiency, wherein the bristles are comprised of synthetic thermoplastic polymeric compositions, and contain longit~l(lin~l channels extenlling along the length thereof, having a depth sufficient to entrap a quantity of abrasive particles such that during brushing with an 5 abrasive toothpaste, contact between the channel entl~ped abrasive particles and the surfaces of the teeth is improved, reslllting in a cleaning efficiency coefficient, CEC, above about 1.5 and, an abr~ion efficiency coefficient, AEC, above about 1.5 while demonstrating suitable bristle wearability.

BACKGROUND OF THE INVENTION

The present invention relates to a toothbrush having improved cleaning and abrasion effici~n~y while ret~ining acceptable wear characteristics.

In the oral hygiene field today, toothbrushing is ordinarily accomplished with a toothbrush which is adapted for use with a dentifrice composition, i.e., a toothpaste, which contains an abrasive substance or material cleei~d to abrasively clean theteeth, i.e., to remove materials thereon, including pellicle, plaque, stains, dental calculus (tartar), and the like.

..... .

The current level of gum disease and tooth loss attributed to gum disease and gum retraction in adults, along with the incidence of gingivitis arnong adults, is an indication of the ineff1ciency of cleansing accomplished with those toothpaste/toothbrush combinations presently comrnercially available. In part, this 5 poor cleaning is also due to the poor toothbrushing habits of a majority of adults which include; brushing only once a day, brushing improperly, and/or failing to brush long enough to effect ade~uate plaque, tartar removal, etc. Clearly, a more efficient toothbrush/toothpaste combination would be helpful.

In toothbrushing, the primary function of the bristle is to rub abrasive particles across the surface of the teeth and thereby remove by abrasive action deposits such as pellicle, stains, plaque, tartar and the like from tooth surfaces.

Accordingly, the tangential contact between toothpaste abrasive and surfaces of the teeth as influenced by toothbrush bristle tips during brushing has a major impact on toothbrushing efficiency.

~nllf~ctllrers of nylon bristle toothbrushes have provided in the past, a variety of toothbrushes designated as "soft," "medium," and/or "hard" to indicate the stiffness of the bristles. For a given thermoplastic polymeric composition, one factor, which predomin~rltly determin~s bristle stiffnes~, is the diarneter of the individual bristles. For exarnple, with nylon 6,12 the "soft" bristles typically have a diameter between 0.008 and 0.009 inches; "medium" bristles have a diameter between 0.009 and 0.012 inches and "hard" bristles have a ~ meter greater than about 0.012 inches.
Polybutylene terephtalate bristles are typically about 0.001 to 0.002 inches smaller in diameter due to the greater wet stiffness of this material over that of nylon 6,12. For all bristles used in toothbrushes, there is generally a m~nllf~ lring or gradingtolerance of about ~ 0.0005 inches.

Soft bristles penetrate crevices between the teeth, while mediurn bristles and the hard bristles stabilize the soft bristles against bending as pressure is applied during brushing. The medium and hard bristles are believed to more effectively clean the surfaces of the teeth while the soft bristles achieve better penetration of crevices and are reComm~n~le~l for their gentleness to soft tissue.
s Studies have shown that the most aggressive mechanical cleansing should be directed toward the tooth surface, with much less so toward the gingival surface and essenti~lly none toward the base of the gingival sulcus. The basis for these observations is as follows:
1. The development of gingival infl~mm~tion and dental caries is most frequently caused by failure to remove dental plaque from the subgingival surface of the tooth and to a much lesser extent materia alba from the gingival surface in the subgingival space. Both dental plaque and materia alba can form within several hours of brushing and therefore frequent mechanical cleansing is ~s.s~nti~t. Materia alba, which consists primarily of an acquired bacterial coating and desql~m~ted epithelial cells, leukocytes and a mixture of salivary proteins and lipids, is a soft sticky deposit less adherent than dental plaque. It can be flushed away with a water spray but more completely removed from the gingiva with mild mechanical cle~n~inE.

2. Dental plaque is formed by oral microor~ni~m~ that syntht?qi7e h~rmfi-l products that are de~lluclive to the tooth and gums when not removed from the gingival sulcus. The toxins formed by these microorg~ni~m~ cause cellular damage to the gingiva with subsequent infl~mm~tion (gingivitis) and eventually destruction of the supporting structures (periodontitis). When gingivitis occurs, vascular dilation, capillary proliferation, engorged vessels and ~ ~i.ch venous retum causes a stretched and thinned epithelium that is sensitive to me~ h~nic~l trauma such as aggressive brushing.

3. Dental plaque with associated gingivitis also causes exposure of the . .

W O 98/04167 PCT~US97/12206 root surface (recession) with increased occurrence of cavities (dental caries).
Exposure of the root surfaces can also occur due ~o faulty brushing by repeated direct trauma to the base of the sulcus (gingival abrasion). When a pathologically deepened gingival sulcus (periodontal pocket) occurs, the pathological condition may become exacerbated because plaque can more readily occur. If dental plaque is not removed, calculus (tartar) is formed by mineralization of the bacterial plaque. Calculus can form within several hours of plaque for nation. Calculus has a bacterial plaque coating and exacerbates gingivitis and gingival recession by both chemical irritation fiom the formed toxins and destruction from the mechanical irritation of the calculus mass.
Subgingival calculus usually extends near but does not reach the base of periodontal pockets in chronic periodontal lesions. Calculus holds the plaque against the gingiva, and 4. Since materia alba can be removed by light mechanical cleansing and gingival infl~mm~tion causes thinning of the gingival epithelium the mechanical cle~nsing requirement of the gingival surface is much less than the requirement for removing dental plaque from the surface of the teeth.

Accordingly, a more efficient cleansing and abrading toothbrush, which fulfills the foregoing requirelllc~ while protecting the base of the gingival sulcus, is desirable.

Review of Prior Art Toothbrush bristles have come a long way from the curly-tusked swine hair they were made from prior to World War II. First was the inkoduction of nylon synthetic fiber in 1938. The popular round toothbrush bristle style introduced in 1938 is used today in more than 50% of the premium toothbrushes used worldwide.

.. . .

Since 1938 nearly all major toothbrush marketers have developed irmovative "cosmetic" features which make their toothbrush offerings unique at the retail shelf.
These features included: colors, p~ck~ging, innovative handle and head ~esi~
trimmin~ alternatives, various tufting arrangements, various bristle lengths, bristle 5 diarneters, etc. Whatever the cosmetic feature(s) promoted, these commercial toothbrushes have typically relied on the basic cylindrical bristle with rounded tips for abrasive/tooth surface contact. See for example, U.S. Patent Nos. 3,217,074,4,898,193, 4,927,281, 4,993,440, 5,020,552 and 5,511,275.

10Recently, uni4ue bristle designs have been designed and commercialized reportedly to improve plaque removal, interdental cleaning, gum care and durability.
All of these recent innovations also rely on the classic bristle tip (usually rounded) abrasive contact with the tooth surface to affect cleaning. See Tynex~ Shapes and Textures Toothbn~sh Filaments "... because specialized cleaning starts at the tips" (H-1550102) published by the DuPont Company, Washington WV 26181, 1995. This publication is hereby incorporated herein by lerelellce.

Summarized below in Table 1 are some recent industry approaches to various consumer toothbrush needs where toothbrush bristle shape, and texture are varied to 20 provide 'lspeci~li7ing cleaning". Note: These approaches are based on bristletip/toolhpa~l~ abrasive interaction to achieve cleansing and abrasion of tooth surfaces.

~ . . .

Table I

Consumer Feature to Address Recommended Tynex~
Need Consumer Need Bristle Construction Interdental Fine tips able to reach Feathered Cleaning farther between teeth.
More bristles per tuft Hexagonal working with every stroke.
Plaque Higher surface contact area Hexagonal Removal increased ability to hold toothpaste at tips. Feathered Higher functional Grainy, Co-Extruded abraslveness.
Compliance with Bass brushing Methods. Rectangular Healthy Gums Gentleness to the gums Feathered, Rectangular End-rounded tips ~11 styles More surface area to Hexagonal distribute force applied to brush Softness of tips Feathered Durability Improved Wear Technology All Styles Superior bristle integrity Hexagonal .

Various cross-sectional geometric bristle shapes have been developed to enh~nre the pelro~ lce of toothbrushes in general. For exarnple, U.S. Patent No.2,317,485 teaches that circular cross-sectional bristles do not pack as efficiently as other shapes such as triangles, squares, pentagon's etc. U.S. Patent No. 2,876,477 5 utilizes polygons with a concave contour on each side to maximize interstitialspacing. The corners of the bristle sides serve as scrapers for the bristles. The multi-fluted sides of these bristles are designed to function in a manner analogous to scaly natural bristles.

Bristle brushes other than toothbrushes with various cross-sectional shapes are disclosed in U.S. Patent Nos. 4,386,325; 4,898,193; 4,167,794, 5,020,551 and5,396,678. U.S. Patent No. 5,396,678 teaches toothbrush bristles having a rectangular cross-sectional shape. U.S. Patent No. 5,020,551 discloses various bristle cross sections including: solid circular, hollow circular, cruciform, and multilobal.
U.S. Patent No. 4,898,193 teaches multi-ridged polygon bristles for combing eyelashes and for applying mascara to the eyelashes. This reference teaches that the sides of the polygon bristle can curve inwardly. Similarly U.S. Patent No. 4,381,325 discloses a liquid-ret~ining synthetic bristle having an acute ridgeline extending longitll~lin~l on its surface. The bristle has at least one convex portion. The arcuate 20 concave grooves were shown to retain more liquids such as India ink than non-ridged co~ ~able brushes.

U.S. Patent No. 3,613,143 discloses toothbrushes with abrasive illJ~-e~ ted bristles of two cross-section ~le~ , i.e., generally circular and polygon with the 25 latter described as having longih~lin~l groove arrang~ t~.

U.S. Patent No. 4,167,794 discloses rounded bristles having shovel-like distal ends for more effective pla~ue removal.

U.S. 4,958,402 teaches fiber-flocking synthetic bristles as a means of ~ .

ret~ining the substance to be applied and more effectively distributing the substance on the surface to be treated. These fiber-coated bristles are taught for use in interdental cleaning. Similarly, U.S. Patent No. 5,195,546 teaches having a gentle random and irregular wavy configuration along the length of the bristles for the5 improved application of powder to surfaces.

U.S. Patent No. 2,312,828 teaches improved abrasive tooth surface contact by forming in the working face of the brush a longitudinal groove or channel of a size to receive and hold a strip of paste squeezed from the tube, this groove or channel being 10 completely closed at its sides and ends by the outside longitudinal and transverse rows of full length bristles, so that the p~te or powder deposits cannot fall from the brush.

U.S. Patent No. 2,599,191 teaches improved toothbrushes for treating gum 15 dise~e where the bristles are looped resulting in a smooth "side surface" contact with teeth and soft tissue.

U.S. Patent No. 2,845,649 teaches a small diameter nylon bristle with higher tuft count produces a "sweeping action" as distinguished from traditionally "coarse"
20 toothbrushes. It is suggested this sweeping action is gentler on soft tissue.
U.S. Patent No. 4,993,440 describes a brush for the application of cosmetic products such ~ m~cara, where the bristle h~ a capillary channel extending from the b~e to the tip. This channel h~ a V-shaped or U-shaped cross section designed 25 to hold the mascara.

Toothbrush constructions of various types have been disclosed throughout the prior art to accommodate access to various components of an individual's mouth during a toothbrushing procedure. Such toothbrushes are exemplified in U.S. Patent No. 4,800,60~ wherein the bristle head is formed having a fixed obtuse angle. See W O 98/04167 PCTnUS97/12206 also U.S. Patent Nos. 3,072,944; 3,188,643; 3,263,258; S,346,678; 5,274,873;
5,335,384; 5,355,546; 5,360,025; S,497,526 and S,511,27S.

U.S. Patent No. 4,729,142 sets forth a toothbrush head having the bristles S directed towards the medial center of the toothbrush head.

U.S. Patent No. 4,852,202 sets forth a toothbrush head having angulated bristles, wherein the bristles include first bristles having an orthogonal orientation relative to the toothbrush head, with a plurality of secondary bristles mounted at a generally forty-five degree angle relative to the toothbrush head.

U.S. Patent No. 3,032,230 teaches bristles with a polygon cross-section having at least two acute angles that impart a "scraping" effect on the teeth. U.S.
Patent No. 3,214,777 teaches bristles with a rect~n~ r cross-sectional area.
See also U.S. Patent Nos. 2,088,839; 3,295,156; 3,722,020; 3,939,520;
4,167,794; 3,217,074; 3,238,553 and 4,927,281.

The prior art also teaches that generally, most adult toothbrushes have bet~veen 2000 and 3000 bristles with between 2300 and 2600 most popular. These bristles are usually arranged in three to five rows with about lS tufts/row. In contrast, a child's toothbrush may have only three rows with approximately 10 tufts ln each row.

Until the present invention, all toothbrush bristle constructions described in the prior art, including round, round/hollow, multi-lobal, rectangular, hexagonal, etc.
type bristles could be characterized as effecting only tangential "point" contact between the bristle tip, the abrasive, and the surface. The present invention represents the next advance in this area, providing greater contact between these elements.

CA 0226l763 l999-0l-20 W O 98/04167 PCT~US97/12206 OBJECTIVES

The present invention thus has as its primary objective the enhancement of tooth cleaning and polishing through improved cleaning and/or abrasion efficiency 5 wherein contact between cleaning abrasives and the toothbrushes of the presentinvention improve tooth surfaces. The improvement in cleaning efficiency is measured by a Cleaning Efficiency Coefficient, CEC, which is defined below. The improvement in abrasion efficiency is measured by an Abrasion Efficiency Coefficient, AEC, which is also defined below.
Another object of the present invention is to efficiently remove plaque and tartar and to provide a smooth tooth surface resistant to plaque and tartar buildup by enhancing the contact between abrasives and tooth surfaces with the improved toothbrushes of the present invention, wherein the abrasive is contained in a 15 toothpaste also having a plaque buildup fighting, active ingredient that coats the freshly cleaned tooth surface with a poloxamer polydimethyl-siloxane emulsion cont~ining coating during the toothbrushing.

A further objective of the present invention is to enhance the cleaning of those20 tooth surfaces contiguous to the gingival margin and to i~ .n~ximal surfaces by improving the contact between the abrasives in toothpaste and these various critical surfaces of the teeth by the toothbrush bristles of the present invention, whereby ~nL,d~ed abrasive is delivered to these critical tooth surface areas during brushing in a manner sufficient to remove plaque, stains and tartar while depositing coating25 substances that help fight plaque and tartar buildup.

A still further object of the invention is to improve the tooth cleaning perforrnance of the majority of toothbrushes who: (a) routinely fail to brush for a long enough period of time, i.e., 20 to 30 seconds vs. two minlltes (as recomrnended 30 by the American Dental Association, ADA); (b) fail to brush frequently, i.e., about r once a day, vs. preferably after every meal and/or snack; and (c) brush with an improper brushing motion on most lingual and buccal surfaces vs. the recornrnended Bass Method of brushing.

S Yet another object of the invention is to m~nllf~ctllre a toothbrush with improved cleaning efficiency coefficient, CEC, of at least about 1.5, along with an improved abrasion efficiency coefficient, AEC, of at least about 1.5 (as definedbelow).

Another object of the invention is to provide a means for efficiently cleaning and polishing hard oral surfaces while avoiding injuring the soft tissue.

A further object of the invention is to adapt the channeled, abrasive ell~l~ping bristles, of the present invention to the various heads of comrnercial toothbrush innovations such as described in U.S. Patent Nos. 3,072,944; 3,188,673;, 3,262,258; 5,274,873; 5,396,678; 5,335,389; 5,355,546; 5,360,025; 5,401,526; and5,511,275.

Another object of the invention is to adapt the channeled, abrasive ~llll~i~lg bristled toothbrushes of the present invention to the various commercial toothpastes, including those described in U.S. Patent Nos. 4,254,101; 4,515,772; 4,999,184;
4,842,165; 4,684,518; 4,885,155; 4,806,339; 5,004,597; 4,806,340; 4,889,712;
4,925,654; 4,591,211; 5,374,368; 5,424,060 and 5,180,576.

Yet another object of the invention is to provide an improved method of caring for the teeth and gums using a toothpaste cont~ining an active ingredient that fights plaque buildup.

... ..... . ... . . .

SIJMMARY OF THE INVENTION

The foregoing and other objects, advantages and features of the present invention are achieved through the use of toothbrushes with novel bristle 5 construction, such as those illustrated in Figs. 1-4. The present invention provides a more efficient toothbrush that has ribs and/or grooves on the bristle periphery. ~hese ribs and grooves are sized and arranged as to trap and hold the toothpaste abrasives and other active ingredients against the teeth and soft tissue surfaces of the mouth more effectively than previously known brush designs.
In the preferred embodiments of this invention, the abrasive and/or tubule closing ingredients contained in various toothpastes are entrapped in longitudinal channels formed in the toothbrush bristles. During brushing these charmel-entrapped-abrasives and tubule closing substances are brought into functional contact 15 with tooth surfaces, resulting in improved cleaning efficiency and/or improved treatment of hypersensitivity. This is illustrated in Figs. 6 and 7. The improved cleaning efficiency is measured by a Cleaning Efficiency Coefficient, CEC, as defined below, as is the improved Abrasion Efficiency Coefficient, AEC.

Specifically, the Cleaning Efficiency Coefficient (CEC) is a number which relates the cleaning efficiency of the novel toothbrush bristle construction to current standard round bristle construction, where both bristle types are tested in an identical head design and tuft placement. One advantage of such a Coefficient is the ability to compare complex variables, using multiple measures of cleaning. For example, such 2~ a coefficient is useful in comparing in vitro removal of artificial plaque, food debris, materia alba, etc. It is equally useful in correlating in vivo measurements on plaque and tartar removal or other clinical indications.
The CEC is a ratio of the efficiency of the test bristle to the efficiency of a standard round bristle under standardized use conditions. The ratio is expressed as the reduction in the parameter measured (plaque, for exarnple) by the test bristle in r - 1 wo 98/Wl67 PCT/uS97/12206 any specific configuration, divided by the reduction in plaque produced by st~n~r~t round bristles under identical toothbrush design and test conditions. See Example I
and Table 4 below. This relationship may be expressed as follows:

BaselineTe51 - FinalTes~
CEC
Baselines,d Round ~ FinalStd. Round "Cleaning Efficiency Coefficient" (or CEC), as noted above is an indicator of the cleaning improvement obtained with the toothbrushes of the present invention, as measured against a standard comprising a toothbrush with bristles of a circular cross-section, with both toothbrushes using the sa~ne abrasive cont~ining toothpaste under standard brushing conditions. The CEC observed after crossover clinical testing, such as described in Example 1, and reported in Fig. 8 and in Table 4, is 2.5%. For purposes of the present invention, CEC values greater than about 1.5 are pl~r~ d. Particularly plerelled are CEC values above about 2Ø

The unexpected improvement in cleaning efficiency as reported in Example l for the quadr~ch~nnel bristled toothbrush of the present invention, can also be expected for various other multi-channel bristle configurations such as those described in Tables 2 and 5 and illustrated in Figures 2-4 of the drawings.
Improvements in AEC are also expected.
In addition to the above reported, yet unexpected and dramatic improvement in clinical cleaning efficiency observations, it has been further found that significant improvement in abrasive cleaning efficiency is achieved with the present invention, without incurring an observable adverse effect on the "soft tissue" contiguous to the teeth. In part this favorable tooth/soft tissue cleaning result is attributed to the "softer"
bristles used in the toothbrushes of the present invention and to the efficient abrasive/tooth contact effected by the multi-channeled bristles of the present ... . .

CA 0226l763 l999-0l-20 W O 98/04167 PCTAUSg7/12206 invention.

For the purposes of the present invention; the Abrasion Efficiency Coefficient (AEC) is defined as the ratio of the results of a standard RDA, Stain Index or 5 Polishing Index procedure of a test bristle brush in a given tuft configuration to the results of an identical procedure using standard round bristles in the sarne tuft configuration. This relationship may be expressed as follows:

Baseline RDATesl - Final RDATest 1 0 AEcRDA
Baseline RDAStd Round ~ Final RDAStd. Round or Baseline Stn IndTest - Final Stn IndTest AECstn Ind Baseline Stn Indstd. Round ~ Final Stn Indstd Round or Baseline Polish IndT~st - Final Polish IndTes, AECpolish Ind Baseline Polish Indstd Round ~ Final Polish Inds,d Round For the purposes of the present invention, AEC values for RDA, Stain Index and Polish Index above about 1.5 are prer~led with values above about 2.0 being particularly ~,ef~l~ed.

Relative Dental Abrasion (RDA) has long been the standard measurement for predicting the perforrnance of a given toothpaste formulation, and/or the functionality of a series of abrasives having varying particle sizes, compositions of matter, crystal structures, fracture edges, etc. Typically a measured number of strokes with a standard toothbrush with a fixed applied pl'eS~iull: against a piece of dental enamel fixed in a holding plate is the basis of the test. Sometimes a plate of soft metal, such S as copper, is substituted for the dental enamel as an inexpensive approximation method. The dental enamel is measured for loss of surface enamel (or metal) by avariety of methods, including weight loss, optical comparison and radioactive techniques.

A similar measurement using artificially stained enamel measures the abrasive removal of stain. In a similar fashion, one can evaluate the polishing of tooth surfaces, a process which increases the reflectance l)ro~e~lies of the enarnel without a high level of enamel removal or "scratching".

As long as the brush, its bristles, and the mechanical parameters are constant, the RDA (and its Stain Index and Polishing Index counterparts) has proven to be the most useful tool available to the toothpaste form~ te For the toothbrush clecigner using only round bristles of a given softness/hardness plopelLy, the RDA is of a lesser value in predicting in vivo performance, even if the abrasive formulation is kept 20 constant, since bristle positioning has only modest impact on the abrasive properties of the chosen abrasive.

In the present invention, the ch~n~ing of the bristle design according to the present specification impacts the abrasivity, both absolute and relative, of differing 25 abrasives and form~ tiQns to a much greater extent. Therefore, to effectivelyappreciate and evaluate the advances of the present invention, it is nçcess~ry to modify the standard ~DA and create a new measurement technique called the Abrasion Efficiency Coefficient (AEC).

It is self-evident that because the c ~ ent and resulting delivery of the abrasive agent to the tooth surface is more efficient as a result of this invention, certain abrasives (especially those with very high relative hardness or sharp crystal edges) will have a higher RDA when applied with these brushes.

Conversely, if a "non-scratching" abrasive is more effectively delivered, it cando a more complete job of removing plaque, or even polishing, without having to possess a high RDA. The advantage of this performance is obvious in that the teeth are more effectively cleaned, both clinically and cosmetically~ without resort to the extent of enarnel darnage previously demonstrated with high RDA abrasive systems.
The longitudinal channel feature of the bristles of the present invention shown in Figs. 1-4 requires a bristle core of sufficient diarneter and strength to achieve:

a) strength/stiffness values and b) bendrecovery/wearvalues such that the wearability of the toothbrushes of the present invention are comparable to comrnercially available toothbrushes with traditional bristle construction.

Were these strength/stiffness and bend recovery/wear values not factored into the channeled bristle designs of the present invention, the toothbrushes of the present invention would fall far short of conventional toothbrushes in the critical area of wearability.

The multi-channeled bristles of the present invention not only provide a substantial improvement in abrasive/tooth surface contact, attributed to ~ apl~ent of effective quantities of abrasive in the channels during brushing, but, in one embodiment of the invention, they also provide a unique interlocking bristle feature.
That is, certain bristles of the present invention during brushing tend to interlock, resulting in less open space between bristles effecting a more contiguous contact with W O 98/04167 PCTrUS97/12206 tooth surfaces, resulting in optimum CEC and AEC values. This interlocking of the channeled bristles of the present invention is best illustrated in Figures 5, 7 and 1 1 (a) of the drawings.

Generally, the bristles of the present invention have sides more adaptable to interlocking and accordingly are readily distinguished from their round cross-section cou~ ~ LS. As a result, toothbrushes of the present invention, with "interlocking"
during brushing produce higher CEC and AEC values than other toothbrushes.

As described in greater detail below, the present invention is based upon the clinical observations that:

1. Best toothbrush action is accomplished by the "sides" of the bristles, rather than by the tips of the bristles. (see Figures 6 and 7) 15 2. Conventional bristles in combination with abrasive particles effect minim~l "bristle driven abrasive cleaning action" during brushing.
3. During toothbrushing the bristles "flex" whereby the sides of the bristles rather than the tips become the "primar,v cleaning contact" area of the toothbrush with the surfaces of the teeth, (see Figures 6 and 7), and 20 4. Means for enL,~phlg abrasive in the sides of toothbrush bristles will improve abrasive/tooth surface contact and cleaning efficiency of the toothbrush.

The current state of the art for toothbrush m~mlf~cturing e",phasizes that:
"superb end-rounding (of bristles) enh~nres gentleness to the gum line area" (see 25 Tynex~ reference, supra). The present invention suggests that channeled bristles entrapping abrasive producing improved CEC and AEC values assures gentleness to the gum line area, that can be clinically subst~nti~te~l End-rounding the bristle tips of the present invention although doable, (See 30 Figures 9 & 10) is not re~uired for achieving comfort along the gum line and W O 98104167 PCT~US97tl2206 avoiding darnage to the delicate gum tissue. That is, the overall softness of the bristles of the present invention in combination with the "flagging" achieved with the multi~channeled bristle tips of the present invention reduces the necessity of end-rounding these bristles. "Flagging" is discussed in detail below. The bristles of 5 the present invention are generally perceived as softer and gentler on gums than most and rounded commercial bristles. The improved CEC and AEC performance of the brushes of the present invention reduces the brushing force required to achieve cleaning, thereby obviating darnage to gum surfaces.

Toothbrushes of the present invention are particularly complementary of the dentist recommended Bass Method for brushing teeth. The Bass Method calls for upand down strokes on the sides of the teeth with back and forth strokes on the tops of teeth. The multi-channeled bristles of the present invention with their entrapped abrasive assure improved abrasive tooth surface contact with both "up and down" as well as "back and forth" strokes of the toothbrush. As a result, effective abrasion cleaning is achieved on the tops of the teeth while soft gentle thorough abrasion cleaning is effected on the sides of the teeth. This entrapped abrasive cleaning of the tops of the teeth and the sides of the teeth is schematically illustrated in Figs. 6 and 7.

It is generally recognized in the art that non-round bristles (which would include the unique multi-channeled bristles of the present invention) provide substantially more softness than colllp~able round cross-section bristles when brushing the teeth with up and down strokes. (See Tynex~ reference, supra). It is suggested that, this softness combined with the inherent gentleness on gums reported for the bristles of the present invention should help reduce gum retraction due to toothbrushing.

Historically, toothbrushing based gum retraction has been considered a major reason for tooth loss along with gum Ai~e~ce The toothbrushes of the present invention with their 'rflagged" tips, and improved CEC and AEC values, promise to r WO 98/04167 PCTtUS97/12206 minimi7e toothbrushing based gum retraction, as detailed below.
The multi-channeled bristles of the present invention are particularly adaptable to splitting at the ends, i.e. "flagging", producing soft fine strands or "feathers" that have been reported to affect efficient interdental and gum cleaning S while still being gentle on gums. These "feathers" at the tips of the bristles offer outct~n~ling clinical benefits including:

(a) Higher contact surface area for the bristle tip which in combination with the channel entrapped abrasive affects unexpectedly improved cleaning efficiency, CEC;

(b) Superior plaque removal without f~m~ging the gum: These soft multi-channeled bristles with feathered tips have the ability to reach further between teeth and gum line areas to enhance interdental and gum line cleaning; and (c) Superior cushion effect on the gums as perceived by subjects and generally described as "gentle on gums" during clinicals.

"Flagging" is described in U.S. Patent Nos. 2,697,009, 2,911,761, 3,295,156, and 5,128,208, the disclosures of which are hereby incorporated herein by reference.

In a pr~rt;"ed embodiment of the invention, as illustrated in Figures l ar~d 5-7, the toothbrush bristles contain longitudinal cavities such as çh~nnçl~ extçn~ling along the length thereof having a depth sufficient to entrap abrasives having a particle size between about 3 and about 25 microns and preferably between about 6 and about 20 microns. Figs. 2 and 3 illustrate various cross-sectional configurations of p~e~lled abrasive entrapping bristles of the invention.

In another embodiment of the invention, the toothbrushes of the present invention are combined with toothpastes that also contain active ingredients that fight plaque buildup to provide an irnproved method of brushing teeth. This combination results in teeth with improved CEC and AEC scores that surprisingly also exhibit an improvement in fighting plaque buildup.
s In a specific embodirnent of the invention the combination of the toothbrushes of the present invention with certain toothpastes, in addition to providing improved cleaning and abrasion of the teeth, including irnproved plaque removal, unexpectedly produce a surprising reduction in plaque buildup. That is, when the toothbrushes of 10 the present invention are used with toothpastes containing MICRODENT~
ULTRAMULSION(~) an unexpected method of reducing plaque buildup is also obtained. Such toothpastes are disclosed in U.S. Application Serial No. 08/461,698, filed June 5, 1995, now U.S. Patent No. . Other preferred toothpaste compositions are disclosed in U.S. Application Serial No.
, Attorney Docket No. 1648/46678, filed on even date herewith. The contents of these two applications are hereby incorporated herein by reference.

It appears the irnproved cleaning and abrasion obtained by the 20 channel-entrapped abrasives contacting the tooth surfaces provides optimum tooth surface preparation which is then followed up by a coating of tooth surfaces with MICRODENT~ ULTRAMULSION~).

When a toothpaste cont~ining MIC~ODENT~) ULTRAMULSION~ is used, 25 those tooth surfaces that have been cleaned with the toothbrushes of the invention generally indicate a most thorough, con~i~tent and effective coating that is well suited to resisting plaque buildup.

Specific preferred embodiments of abrasive e~lll~ping bristles according to 30 the present invention will now be described with reference to the accompanying r W O 98/04167 PCT~US97112206 drawings. In the description that follows, specific bristle constructions will be used-for purposes of clarity, but these are not int~n~ed to define or to limit the scope of the invention, which is defined solely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figs. lA and lB are srh~ tic side views illustrating a 0.012 inch cross-section bristle embodying an abrasive entrapping channel of the invention, wherein the channel depth is about 0.003 and the channel breadth is about 0.006.
In Fig. lA the bristle channel is shaded in order to accentuate the abrasive entrapping feature to be described hereafter.

Figs. 2A, B and C r~p~esel,t the present invention various tri-channeled cross-15 sectional bristle shapes applicable to the improved Cleaning Efficiency Coefficient(CEC) and Abrasion Efficiency Coefficient (AEC) toothbrush of the present invention.

Figs. 3A, B and C represents various quadra-channeled cross-sectional bristle 20 shapes with various "channeling" suitable for the improved Cleaning Efficiency Coefficient (CEC) and Abrasion Efficiency Coefficient (AEC) toothbrush of the present invention.

Fig. 4A, B and C l~resellt various poly-channel cross-sectional bristle shapes 25 with various channeled bristles suitable for delivering the CEC and REC values of the present invention.

Fig. 5 is a perspective plan view of a toothbrush tuft of the present invention illustrating the tuft arrangement of one of the bristles of the present invention.

Fig. 6 illustrates sehem~tically, the general contact between the channeled bristles of the present invention cont~ining entrapped abrasive, and the tooth surface, during brushing.

S Fig. 7 illustrates schç~n~tic~lly a m~gnified view of the contact between bristle-channel-el.tl~ped abrasives and interproximal surfaces of the teeth during brushing with an abrasive cont~ining toothpaste.

Fig. 8 is a bar chart that compares the average plaque scores for a quadra-channeled bristle toothbrush of the present invention compared to a toothbrush with round bristle configuration when both are used in a crossover clinical study, with a common commercial toothpaste, as described in detail in Example 1.

Figs. 9 and 10 are electron microphotographs of tips of toothbrush bristles of the present invention, and a conventional round toothbrush bristle tips.

Figs. 11 (a) illustrates schem~tically a m~nified view of a cross-section of the"packing" of one of the bristles of the invention into a tuft with the bristle interlocking feature of the present invention (1 lA) compared to the cross-section packing of rounded bristles into a tuft Fig. 11 (b).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of the present invention, multi-sided channeled bristles are defined as toothbrush bristles that have been formed in a multi-channeled cross-section shape, wherein at least three, p,eÇe,dbly four, most ple~l~bly five like-shaped individual channels are provided at the lower (i.e., tip) end of each bristle. The individual channels are thus capable of ~lllla~pi~lg appreciable quantities of abrasive particles during brushing with a toothp~te, and the ellll~ped abrasive particles will be delivered to the surface of the teeth with a force su~cient to affect improved r cleaning and abrasion efficiency, while avoiding abrasion of the enamel dentin and while avoiding adversely affecting the soft tissue.

For the purposes of the present invention, a "channel" is defined as a S depression, hollow or cavity, which preferably extends the entire length of each bristle, wherein the cavity is of sufficient depth to accommodate sufficient toothp~te abrasive such that the entrapped abrasive is delivered to the tooth surface during brushing with a force from the channeled bristle sufficient to effect a CleaningEfficiency Coefficient (CEC), of at least about 1.5, and an Abrasion Efficiency 10 Coefficient (AEC), of at least about l.S.

In one ~ ed bristle dimension of 0.012 inches in diameter as shown in Fig. 1, the plef~,led channel is about 0.013 inches deep with a breadth of about 0.006 inches. See also Figs. 2-7 and 1 1 (a) and Tables 2, 3 and 5. The dimensions of the 15 çh~nnel.c are described in various Examples as set forth below. For example, at bristle ~ m~t~rs ranging from between about 0.008 and about 0.014 inches, channel depths from between about 0.007 and 0.00S inches are disclosed along with a channel breadth ranging from between about 0.003 and 0.006 inches. It is understood that for larger diameter bristles these channel depth and breadth values may increase 20 subst~rlti~lly.

For the purposes of the present invention a toothbrush is defined as any m~ml~l, inte~u~ilnal, or mechanical toothbrush cont~ining multiple tufts of thermoplastic polymeric bristles, and specifically includes the various cornmercially 25 available toothbrush handles and head designs popular today, as well as the various tuft arrangements, bristle variations, including various lengths of bristles and bristle bundle packs. These toothbrushes are marketed in the U.S. under tr~d~m~rk.
including: Braun~, Interplak~, Oral-B~), Complete~, Precision(~3), Total(g), REACH(~, MentaDent~, IUMTM, Gumg), InterPlak~, Oral Logic, etc. Various 30 toothbrushes as described in the following U.S. Patents are suitable for adaptation of ~ . . .. . ... ...

W O98/04167 PCTrUS97/12206 the bristles of the present invention: 3,072,944,3,188,673,3,263,258,5,396,678, 5,274,873,5,335,389,5,355,546,5,360,025,5,497,526, and 5,5l1,275. The teachings of these references are to be included in this specification by reference.

Suitable bristles of this invention having various cross- sectional shapes are illustrated in Figs. 2 through 4 and .li.cc.l~sed in detail in Tables 2-5 below.
Referring now to Figures 6 and 7, the channel entrapped abrasive 10, is brought into contact with the various surfaces of the teeth 11 by bristle 12 in a wiping mechanism of action. In other words, upon flexing of bristle 12, bristle channel 13 achieves extended abrasive/tooth surface contact as illustrated at 6 and 7. In the wiping action, this surface contact is m~int~ined between the bristle channel 13 and the tooth surface.

The polymers useful with the bristles of the present invention may be prepared by methods now well know in the art such as the procedures described byG. Notta in the Journal of Polymer Science, Vol.~rVI.pp.143 to 154(1955) and in U.S. Patent Nos. 2,882,263;2,874,153;2,913,442;3,112,300 and 3,112,301 the disclosures of which are hereby incorporated herein by reference.

The bristles may be formed by melt extruding various thermoplastic polyrneric materials through a~plup~iately shaped extrusion orifices in various dies following various processes such as described in U.S. Patent Nos. 2,226,529 and 2,418,482;3,745,061;3,238,553;3,595,952;4,279,053; French Patent No.
2,125,920, and European Patent Appln. No. 0663162171.

The tufting, cutting, staplin~, etc., of the bristles is performed by processes known in the art; for instance as described in U.S. Patent Nos. 4,441,227;4,688,857;
979,782;5,274,873;5,335,389; and 5,511,275, the disclosures of which are hereby incorporated herein by reference.

r For the purposes of the present invention, thermoplastic polymeric compositions suitable for the bristles of the present invention include synthetic linear con~Pnc~tion polyamides, such as described in U.S. Patent Nos. 2,071,250, 2,071,251, 2,130,948 and 3,671,381.

The synthetic polyamides useful in the bristles of the present invention includes those which are of sufficient molecular weight to be fiber-forming such as:
polycaprolactam, polyhexamethylene adipamide, polyhexamethylene sebacamide, the polyamide formed from 1,4,(cis)cyclohexane-bis(methylamine) and adipic acid (seeU.S. 3,012,994); the polyamide from m-xylene diamine and adipic acid (see U.S.
2,916,475); the polyamide from 3,5 dimethyl hexamethylene diamine and terephthalic acid (see U.S. 2,752,358); the polyamide from 2,5 dimethyl piperazine and adipyl chloride (see U.S. 3,143,527). See also U.S. 2,152,606. The p,efell~dpolyamides are polyhexarnethylene adipamide; and polyhexarnethylene sebac~mi~le In general, the number average molecular weight of the polymer used for these bristles should be in excess of 10,000 and preferably greater than 30,000 to provide the strength and stiffness needed in a toothbrush bristle. The commercial polyarnides preferred include nylon 6,6; nylon 6,10 and nylon 6,12. Ofthese nylon 6,10 (polyhexamethylene sebac~mic~e) and nylon 6,12 (hexamethylene diarnine are particularly p.efelled. See Table 2.

Polyesters that have been found particularly well suited to the bristles of the present invention include polybutylene terphth~l~te and polyethylene terephtalate.
(See Tables 3 and S below).

The overall diameter, or maximum cross-section for the bristles of the present invention can be between about 4 and 20 mils. Bristles outside this range, in general, will exhibit stiffilPss~ which is lln~llit~ble for toothbrush bristle applications of the invention. The bristles generally extend from between about 8 and 15 mIn above the toothbrush head.

It is known that bristles of thermoplastic materials may have their properties 5 enhanced by drawing or stretching the bristles to increase the molecular orientation along the fiber axis. Therefore, it is ple~lled to stretch orient the f1larnents used to make the bristles of the present invention or to apply other standards property-enhancing processing to the techniques thereto.

Examples of other thermoplastic polymeric compositions from which the bristles of this invention may be formed include: polyolefins such as polyethylene and polypropylene; polyacrylics such as polyalc~ylonitrite, polyacrylamide, copolymers of acrylonitrile with methyl methacrylate, etc.; polyvinyl chloride and copolymers of vinyl chloride with other vinyl monomers, polymers of fluorinated 15 olefins such as polytetrafluoroethylene; polystyrene; and the like.

Additionally, the uniquely channeled cross-sectional shapes of the bristles of the present invention can be co-extruded from two or more distinct thermoplasticpolymeric materials.

For example, a polybutylene terephtalate core can be co-extruded with a multi-channeled sheath of 6,12 nylon to produce a multi-channeled bristle that has a smaller diameter core than an extruded polybutylene terephtalate multi-channeledbristle. Such co-extruded multi-channeled bristles combine the best properties of 25 different thermoplastic polymeric m~tçn~l~ to create co-extruded bristles with functional versatility including improved stiffn~s~ softness, increased "packing", etc.
Some of those are described in the Tvnex~) publication referenced above.

It is well known to those skilled in the art of toothbrush design and 30 m~nllf~cture, that the bristle and its resulting "tuft" must possess certain OplilllUln r characteristics commonly described, for example, as (a) softness, (b) flex strength, (c) recovery, (d) wet strength, (e) bendability, (f) permanent deformation, and others.

Typically, this requires balancing parameters such as (a) polymer type, (b) diarneter of bristle (c) end rounding, (d) fl~gging, (e) extent of orientation during bristle drawdown, (f) bristle length, and others.

It will be equally clear to those skilled in the art that similar commercial optimization is required for each of the novel bristle of this invention. In addition to the parameters balanced when studying round bristle construction, one must additionally consider such parameters as, for example, (a) the dimensions of the"core" around which the channels are arranged, (b) the dimensions of the sides of the channels and (c) the internal dimensions of the channel itself. Generally, it isp,e~l,ed that the channel depth is approximately lO to 30% ofthe bristle diameter, as measured at the maximum cross-section, where the channel breadth can vary from between about 10 to about 60% of the bristle diarneter. In a particularly plef~lled embodiment of this invention, a penta-channel bristle having a maximum cross-section diarneter of about 0.012 inches, has five channels with an average depth of about 0.003 inches and an average channel breadth at the center of the channel of about 0.006 inches. See Figure 1 of the drawings.

The currently prefell~d embodiment of the bristle design of the present invention is a five-sided star shape bristle. While the f1ve-sided star shape has been selected as the first cornmercial embodiment, due to its mouth-feel, clinical results, 25 and ability to withstand deformation or "wear-out" during a simulated one-to-three month wear test, it is anticipated that other star shapes will also prove to be commercially viable. Accordingly, it is anticipated that other bristle ~esi~n~, e.g., 4, 5, 6, etc. sided stars (or other shapes) having dimensions which vary from that of the ~iullclltly p,e~.led embodiment will also prove useful in this invention.

W O 98/04167 PCTrUS97/12206 One practical side-effect of providing the multi-channel bristles of this invention is that industry standards deter nined by experience over the years for round bristle parameters may need to be altered for charmeled bristles. Thus, each channeled bristle should be optimized in its own right. For example, a round bristle made of 6,12 nylon with a 0.008" diameter will exhibit certain desired commercial properties described as a "soft toothbrush, where as a channeled bristle may require a larger total diameter and careful attention to the "core" dirnension or even a different polymer in order to achieve the same properties. This is illustrated in Table 2 below.

r Table 2 Bristle Properties RESIN TYPE NYLON 6,12 NYLON 6,12 NYLON 6,12 NYLON 6,6 NYLON 6,6 NYLON6 NYLON6 Bristle Shape Trichannel X-shaped Quadrachannel Pentachannel Hexachannel Cruciforrn Octafoliate D
Size (inch) .006-.040 .008-.020 0025-.005 .006-.043 .005 .006-.040 .005 ~
Specific gravity ~, (g/cm3) 1.04-1.05 1.04-1.05 1.13-1.14 1.13-1.13 1.13-1.14 1.13-1.14 1.13-1.14 Tensile Strength r~ ~
(psi) in m 50-60 50-60 50-60 60-70 60-70 50-60 50-60 , ~
Tensile elongative (%) 45-65 45-65 45-65 35-50 35-50 35-50 35-50 Melting Point ~F 403-419 403-419 403-419 500 500 410-436 410-436 Dry Stiffness Modulus (psi) in m 450 450 450 500 500 450 450 2 Wet Stiffness Modulus (psi) in m 415 425 425 180 180 65 65 o W O 98/04167 PCT~US97/12206 Polybutylene terepht~l~te bristles illustrative of the toothbrushes of the present invention are described in Table 3 below.

r Table 3 Ci Therrnoplastic Polybutylene terephtalate Bristles ,~

BristleShape Trichannel Tetrachannel (X) Pentachannel Hexachannel Diarneter (inch) 0.010 0.008 0.007 0.014 Channel Depth(inch) 0.003 0.0025 0.0025 0.002 O
Channel Breadth (inch) 0.006 0.0045 0.0040 0.003 ~, Sp. Gravity(g/cc) 1.32 1.32 1.32 1.32 1 ~, Tensile Strength(psi) 40-50 40-50 40-50 40-50 l o TensileElongation(%) 35-55 35-55 35 55 35 55 ~
Melt Point (~F) 435 435 435 435 Dry Stiffness Modulus (psi) 320-365 320-365 320-365 320-365 Wet Stiffness Modulus (psi) 300-340 300-340 300-340 300-340 ~;

W O 98/04167 PCT~US97112206 For the purposes of the present invention, abrasive is defined as traditional toothpaste abrasives as discussed in detail below, wherein the particle size (mean diameter) is between about 3 and about 25 microns.

Particularly pler~lled are abrasive mixtures where the secondary abrasive is thetype used in translucent dentifrice gels at levels up to about 20%. Some of these mixtures are described in the following U.S. Patent Nos. 3,927,200; 3,906,090;
3,937,321; 3,911,102; 4,036,949; 4,891,211; 4,547,362; 5,374,368; 5,424,060;
5,180,576; 4,943,429; 4,160,022. Some of these mixed abrasives are commercially available, e.g., Sylodent 15, Sylodent 2 (W.R. Grace), Aerosil 200 (Degussa) andCabosil (Cabot).

The size of the abrasive particles are most commonly expressed in "mean diameter" i.e., the arith~netical average of the diameters of particles in a representative sample. The mean diameter value of abrasive particles is usually described in microns. Abrasives having particle sizes between about 3 and 25 microns and preferably between about 6 and about 20 microns are particularly preferred for the channel designs of the toothbrush bristles of the present invention.

The plt;palalion of suitable particle size abrasives can be accomplished by conventional techniques well known to the art. Basically, these techniques involve milling various abrasive materials, followed by standard screen sieving (or air separation) to segregate the desired particle size range.

Ple~elled plaque and tartar fi~htin~ active ingredients that help control plaque and tartar buildup when included in a toothpaste are the surfactant/polydimethyl-siloxane hot melt emulsions commercially available under the tr~ m~k MICRODENT~.
These are described in U.S. Patent Nos. 4,950,479 and 5,032,387. Particularly Ille~lled plaque and tartar fightin~ active ingredients are surfactant/polydimethyl-siloxane emulsions where the polydimethyl-siloxanes are high molecular weight r subst~n~es Such surfactant -polydimethyl-siloxane emulsions are described in pending U.S. Patent Application Serial No. 08/144,778 and related applications.
These are available commercially under the tr~dem~rk UL~AM~LSION~. See Examples 6-9 below for improved methods of fighting tartar, plaque and stains 5 utili~ing the toothbrush of the present invention with certain toothpastes that capitalize on the clean tooth surfaces obtained with the toothbrushes of the present invention.

The present invention will be further illustrated with reference to the following 10 examples which aid in the underst~n~ing of the present invention, but which are not to be construed as limitations thereof. All percentages reported herein, unless otherwise specified, are percent by weight. All temperatures are expressed in degrees Celsius.

.. . . ... . . .

CA 0226l763 l999-0l-20 W O 98/04167 PCT~US97/12206 EXAMPLE I

In a crossover clinical toothbrushing study, patients brushed with a quadrachannel bristle toothbrush and/or a contour rounded bristle toothbrush and then switched to 5 the other toothbrush. The ends of the bristles in these brushes are shown electron micrographs in Figs. 9 and 10. Plaque scores were established before and after brushing with each brush.

The results are reported in Table 4 below and in Figure 8. The CEC values for this quadr~ch~nnel bristled brush were substantially greater than 1.5, i.e., about 2.59.
This was a statistically significant value with (p = 0.001), even with the smallnumber of subjects per cell.

W O98/04167 PCTnUS97/12206 Table 4 Data Sumrnary of the Crossover Clinical Study Quadr~rh~nn~.l Round Subject Before After Difference Before After Difference 02 2.20 0.82 1.38 2.29 1.88 0.41 03 1.85 0.63 1.22 2.26 1.62 0.64 04 1.58 0.57 1.01 1.96 1.40 0.56 06 1.60 0.55 1.05 1.83 1.36 0.47 07 2.30 1.73 0.57 2.30 1.97 0.33 09 2.06 1.26 0.80 1.94 1.82 0.12 2.03 0.99 1.04 1.79 1.78 0.01 Il 2.19 1.20 0.99 2.27 1.84 0.43 12 2.49 1.16 1.33 1.79 1.78 0.01 13 2.09 1.48 0.61 2.37 2.05 0.32 14 3.67 2.00 1.67 3.38 2.21 1.17 Average 2.19 1.13 1.06 2.20 1.79 0.41 Std. Dev. 0.56 0.48 0.33 0.45 0.26 0.33 Min. 1.58 0.55 0.57 1.79 1.36 0.01 Max. 3.67 2.00 1.67 3.38 2.21 1.17 ....

W O 98/04167 PCTrUS97/12206 Examples 2 through 5 Exarnples 2 through 5 below are illustrative of various unique toothbnush/toothpaste embodiments of the present invention. These Examples are shown in Table S below.

r .

WO g~/04l67 PCT/US97/12206 Table 5 Example No. ~ 2 3 4 5 Bristle Polybutylene Polypropylene Polybutylene Polyacrylo-Thermoplastic terephtalate terephtalate nitrate Polymeric Material Bristle Shape Hex~ch~nn~led X-shaped Cruciform Pentachannel No. of Bristles/Tuft and No. of Tufts in 6120 8/30 4/15 l0/24 Toothbrush Head Particle size of toothpaste 3-6 6-20 3-25 6-18 abrasive in microns CEC in % l0 65 30 70 Antiplaque/
Anti-tartar ~lCRODENT~) MICRODENT~) ULTRA- ULTRA-Active 12,000 1500 MULSION~ MULSION~
ingredienVand 2.5 million cs 50 million cs mol. wt. of polydimethyl-siloxane . . . . ... .

Examples 6-9 Using standard toothpaste fonn~ ting procedures such as those taught in U.S.
Patent No. 4,254,101, the ULTRAMULSION(~) cont~ining toothpastes identified 5 below in Table 6 were prepared. All percentages reported below are percent by weight. PDMS is an abbreviation for polydimethyl-siloxane.

r W O 98/04167 PCTrUS97/12206 Table 6 ULTRAMULSION~) Toothpaste Example No. 6 7 8 9 Ingredients (wt. %):
Deionized Water 16.87 30.44 43.76 16.87 Sorbitol-70% Aq. 18 24.6 20 18 Glycerin 10 8 10 10 Dicalcium Phosphate 49 x x 4g Al~minnm Oxide x 10 x x Hydrated Silica x 20 19 x Cellulose Gum 1 0.8 x Xanthan Gum x x 0.9 x Sodium Monofluoro Phosphate 0.76 0.76 0.76 0.76 Titanium Dioxide 0.5 0.4 0.6 0.5 Sodium Saccharin 0.27 0.2 0.28 0.27 PEG-8 x 1 0.8 x Flavor 0.8 1 0.9 0.8 Sodium Lauryl Sulfate 0.8 0.8 1 0.8 UL~?AMULSION
(2,500,000 cs PDMS) 2 x x x ULT~MULSION
(50,000,000 cs PMDS) x 2 x x ULTRAMULSION
(12,500 cs PMDS) x x 2 x ULTRAMULSION
(1,500 cs PMDS) x x x 2 W O 98/04167 PCT~US97112206 Example 10 Comparison of Penta-Channeled Bristles of Varying Channel Depth With Round Bristles (polybutylene terphthalate) s Clinical Protocol:
Nineteen subjects, screened for good oral health were instructed to refrain from brushing for 24 hours. The plaque of each subject was stained and scored for Plaque lltili~ing a standard method (Turesky modification of Quigley-Hein). The subjects then took their assigned brush and assigned toothpaste (Colgatel~ Fluoride Toothpaste) and brushed without benefit of a mirror for one minute, after which they were re-stained and residual plaque was re-scored using the sarne ~ndex. Each of the nineteen used each brush in trials one week apart so the subjects were their owncontrol. Between trials the subjects retumed to their normal oral hygiene habits, assuring a constant retum to baseline.

All toothbrushes tested were identical in shape, number and placement of bristles and by the naked eye, appeared to be completely identical. Only microscopic ~x~min~tion of the bristles for the presence of channels could disclose a difference.
The toothbrush shape selected for this trial was the very popular "diarnond head"
shape comrnercially available as Colgate PlusA and numerous private label brands.

Results: -2S As shown in Table 7 below, there is a dramatic difference in plaque removal comparing the channeled bristle to the round bristle. There is likewise a distinct correlation between channel depth and relative plaque removal. These differences are statistically significant (p < 0.0001) after a single brushing. Although both penta-channeled bristle designs were effective, these data suggest that the deeper thechannel, the greater the effectiveness on cleaning.

Table 7 Comparison of Pent~h~nnel Bristles of Varying Depth With Round Bristles (polybutylene terphthalate) x ROUND PENTACHANNEL (1) PENTACHANNEL (2) ~' Outside diarneter0.007 0.007 0.007 (inch) CHANNEL -0- 0.0012 0.0009 DEPTH (inch) PLAQUE INDICES (Std. Dev.) INDEX Before After Before After Before After Brushing Brushing BrushingBrushing Brushing Brushing WholeMouth 2.28(0.27) 1.81 (0.27) 2.21 (0.5)1.04(0.44) 2.23(0.31) 0.83(0.36) .
Proximal 2.40 (0.24) 1.99 (0.28) 2.38 (0.11)1.13 (0.12) 2.34 (0.28) 0.88 (0.39) Surfaces Posterior 2.43 (0.23) 1.94 (1.94) 2.29 (0.41)1.14 (0.47) 2.38 (0.29) 0.92 ~0.37) ~, Surfaces o Smooth Surfaces 2.04 (0.32) 1.45 (0.27) 1.87 (0.57)0.88 (0.35) 2.03 (0.37) 0-74 (0-30) (I) There was no statistical dil~-el-ces between the "Before Brushing" means for any bristle shape using any of the reported Indices. (ANOVA) (2) Underlined means are statistically sigmificamt (p < 0.0001) from their l?OUND "Af er Brushing" cohort. (paired t-test) ~.
o Example 1 1 Comparison of Round Bristles of Two Polymer Types 5 With Pent~ch~nneled Bristles This protocol was i~l~ntic~l to the previous Example except that there were five (5) subjects using the round nylon bristle and the pentachannel PBT bristle in 10 this trial. The toothbrushes were also of the same construction as in Example 10 and not rliscenlibly diffelent to the naked eye.

The results comparing a nylon round bristle, a PBT round bristle and a PBT
pentachannel bristle are set out in Table 8 below. The column of data for the round PBT bristle is the same as in the previous Example. In spite of the disparity in the number of subjects tested, the statistical .ci~nific~nce remained and this experiment clearly indicates that it is the presence of the channels which contributes to the greater removal of plaque in a single brushing, whereas the polvmer selected form~nllf~cturing the bristle did not produce a comparable effect on the plaque removing properties.

However, standard wear tests of various bristles suggest that channeled bristle toothbrushes constructed of polybutylene terephtalate are plet~lled over comparably channeled bristle toothbrushes constructed of nylon (TYNEX~).

r T

Table 8 Comparison of Two Round Bristle Types with One Pentachannel Bristle Type NYLON (TYNEX(E~)) PBT PBT O~
ROUND ROUND PENTACHANNEL
Outside diarneter (in)0.007 0.007 0.007 CHANNELDEPTH(in) -0- -0- 0.001 WHOLE MOUTH PLAQUE INDEX (Std. Dev.) ~
Before After Before After Before After ~, Brushing Brushing Brushing Brushing Brushing Brushing 2.14(0.10) 1.79(0.06) 2.28(0.27) 1.81(027) 2.17(0.13) 0.95(0.18) Footnotes:
1. PBT = polybutylene terephtalate.
2. PLAQUE INDEX = Turesky modification of Quigley Hein. "~
3. Underlined mean was statistically significant (p<0.0006) difference when compared to either "After Brushing" with round ~i bristles. (unpaired t-test) 4. There was no statistical significance between any "Before Brushing" means. (ANOVA) The present invention has been described in detail, including the prefelled embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of the present disclosure, may make modifications and/or improvements on this invention and still be within the scope and spirit of this 5 invention as set forth in the following claims.

r

Claims (26)

WHAT IS CLAIMED IS:

1. A toothbrush having improved cleaning efficiency, wherein the toothbrush bristles are composed of a synthetic thermoplastic polymeric composition and comprise a multiplicity of groups of multichanneled bristles, wherein lateral surfaces of said bristles contain at least two longitudinal channels extending along the length of said bristles, said channels having a depth sufficient to entrap a quantity of toothpaste abrasive, having an average particle size between about 3 and about 25 microns; wherein the cleaning and abrasion contact between said quantity of abrasive entrapped in said channels and the surfaces of the teeth is improved during brushing, resulting in a cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5.

2. A toothbrush according to claim 1, wherein the lateral surface of said bristles comprise from between about 3 and 8 channels extending substantially the length of the bristles.

3. A toothbrush according to claim 2, wherein said bristles have crosssectional configurations as illustrated in Figures 2, 3 and 4 of the drawings accompanying this specification.

4. A toothbrush according to claim 2, wherein the cross-sectional configuration of said bristles comprises three or more channels, shaped to readily accept a quantity of abrasive having an average particle size between about 6 and about 20 microns.

5. A toothbrush according to claim 1, wherein the bristles have a diameter between about 0.008 and 0.014 inches, a channel depth between about 0.002 and 0.005 inches and a channel; breadth between about 0.003 and 0.006 inches.

6. A toothbrush according to claims 1, wherein the bristles interlock during brushing.

7. A toothbrush according to claim 1, having a cleaning efficiency coefficient of at least about 2.0 and an abrasion efficiency coefficient of at least about 2Ø

8. A toothbrush according to claim 1, wherein the bristle tips are flagged.

9. A toothbrush according to claim 1, wherein the bristles are formed by melt extruding a synthetic thermoplastic polymeric composition selected from thegroup consisting of synthetic linear condensation polyamides, polyolefins, polyacrylics, polyacrylamides, copolymers of acetonitrile with methyl methacrylate, polyvinyl chloride, copolymers of vinyl chloride with other vinyl monomers, polymers of fluorinated olefins and polystyrene.

10. A toothbrush according to claim 9, wherein the bristles are formed by melt extruding nylon.

11. A toothbrush according to claim 9, wherein the bristles are formed by melt extruding polybutylene terephtalate.

12. A toothbrush according to claim 9, wherein the synthetic polyamide is Nylon 6,12.

13. A toothbrush according to claim 9, wherein the synthetic polyamide is Nylon 6,6.

14. A toothbrush according to claim 9, wherein the synthetic polyamide is Nylon 6.

15. A toothbrush according to claim 1, wherein the abrasion efficiency coefficient values for one or more of RDA, Stain Index and Polishing Index are above about 1.5.

16. A method of gently cleaning teeth and soft tissue in the oral cavity comprising brushing with an abrasive containing substance in combination with a toothbrush having improved cleaning efficiency and abrasion efficiency, wherein:(a) the average particle size of said abrasive is between about 3 and about 25 microns, (b) said toothbrush comprises a multiplicity of groups of multichanneled bristles, wherein lateral surfaces of said bristles contain at least two longitudinal channels extending substantially along the longitudinal length of each bristle, with said channels of a depth sufficient to entrap a effective quantity of said abrasive, and (c) the contact between said abrasive entrapped in said channels and surfaces of the teeth is improved during brushing, resulting in a cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5, without adversely effecting the soft tissue in the oral cavity.

17. A method of manufacturing a toothbrush having improved cleaning and abrasion efficiency, comprising securing several bundles of multi-channeled bristles to a conventional toothbrush head/handle arrangement, wherein the lateral surfaces of said bristles contain at least two longitudinally extending channelssubstantially along the length of said bristles, with said channels having a depth sufficient to entrap an effective quantity of abrasive, said abrasive having an average particle sizes between about 3 and about 25 microns, whereby the use of said toothbrush during brushing resulting in a cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5.

18. A method according to claim 17, wherein said lateral surfaces of said bristles are quadrachannel shaped to readily deliver effective quantities of said abrasive to the surfaces of the teeth, gurns and tongue during brushing.

19. An improved method of cleaning tooth and soft tissue surfaces in the mouth comprising brushing said surfaces with toothbrush bearing an abrasive based toothpaste containing a plaque fighting active ingredient comprising an emulsion of a polydimethyl-siloxane in a nonionic poloxamer surfactant, and wherein the toothbrush comprises multichanneled abrasive entrapping bristles and contact between said abrasive and said tooth and soft tissue surfaces during brushing isimproved over conventional nonchanneled bristle toothbrushes, with an improved cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiencycoefficient of at least about 1.5.

20. An improved method of mechanically cleansing plaque, tartar, stains, and materia alba from tooth surfaces in the mouth while avoiding gingival abrasion and protecting the base of the gingival sulcus comprising brushing said tooth surfaces with toothbrush bearing an abrasive based toothpaste containing a plaque fighting active ingredient comprising an emulsion of a polydimethyl-siloxane in a nonionic poloxamer surfactant, and wherein the toothbrush comprises multichanneled abrasive entrapping bristles and contact between said abrasive and said tooth surfaces during brushing is improved over conventional nonchanneled bristle toothbrushes, with an improved cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5.

21. An improved method of mechanically cleansing teeth with an abrasion wiping action wherein a toothbrush with abrasive entrapping multi-sided, channeled bristles is used in combination with a toothpaste containing abrasive having an average particle size between about 3 and 25 microns, the use of said toothbrush and toothpaste resulting in an improved cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5.

22. A method of enhancing the cleaning of tooth surfaces contiguous to the gingival margin and to interproximal surfaces comprising; combining an abrasive based toothpaste with a toothbrush containing a multiplicity of multi-channeled bristles, wherein the lateral surfaces of said bristles contain channels extending substantially the length thereof, said channels having a depth sufficient to entrap an effective cleansing amount of abrasive particles having an average particle size of between about 1 and 25 microns, such that the contact between said entrapped abrasive and tooth surfaces resulting in an improved cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5.

23. A toothbrush having improved cleaning efficiency, said toothbrush comprising a multiplicity of bristles wherein lateral surfaces of said bristles contain at least one longitudinal channel extending along the length of said bristles, saidchannels having a depth sufficient to entrap toothpaste abrasive having a particle size between about 1 and about 7 microns; wherein the contact between said abrasive entrapped in said channels and surfaces of the teeth is improved during brushing, resulting in a cleaning efficiency coefficient, CEC, from between about 20% and about 90%.

24. A toothbrush according to claim 23, wherein the lateral surface of said bristles comprise a multiplicity of channels extending the entire length of the bristles.

25. A toothbrush according to claim 24, wherein said bristle channels are selected from trichannel, quadrachannel, pentachannel, hexachannel and heptachannel configurations in cross-section, or combinations thereof.

26. An improved method of treating hypersensitive teeth in the oral cavity comprising brushing teeth and gums with a tubule blocking active ingredient contained in a toothpaste in combination with a toothbrush having improved hypersensitivity treating and cleaning efficiency wherein:
(A) the active ingredient is selected from the group consisting of potassium nitrate, potassium oxalate, sta~~ous fluoride and zirconium chlorides and abrasives and mixtures thereof, (B) said toothbrush comprises a multiplicity of groups of multi-sided bristles, wherein lateral surfaces of said bristles contain at least one longitudinal channel-extending along the length of said bristles, with said channels of a depth sufficient to entrap said active ingredient, and (C) the contact between said active ingredient entrapped in said channels and the surfaces of the teeth including those tubules responsible for hypersensitivity is improved during brushing resulting in improve active-ingredient treatment of the hypersensitive tubules, said toothbrush further providing an improved cleaning efficiency coefficient of at least about 1.5 and an abrasion efficiency coefficient of at least about 1.5, incomparison to round bristle toothbrushes.