Non-crystalline saliva-soluble coatings for elastomeric monofilament dental tapes

[0002] This application claims priority from copending U.S. Provisional Application Serial No. 60/263,220, filed Jan. 22, 2001, the disclosure of which is hereby incorporated herein by reference.

[0003] The present invention relates to improved dental tapes. Specifically, the improved dental tapes of the present invention contain substantially crystal-free coatings that: (a) comprise from 20 to 120% by weight of the floss filament, (b) are saliva soluble and (c) exhibit a minimum of flaking. Yet these coatings are released in total into the oral cavity during flossing and can contain ingredients such as abrasives that work with the tape to help physically remove biofilms from interproximal and subgingival surfaces, and chemotherapeutic ingredients affecting oral health and subsequent systemic diseases caused or exacerbated by poor oral health. These coatings are particularly adapted to monofilament dental tapes.

[0004] Historically the purpose of dental floss was: (1) to dislodge and remove decomposing food material that accumulated at interproximal and subgingival surfaces and could not be removed by brushing or rinsing, and (2) to dislodge and remove bacteria, plaque and/or calculus that accumulated since the previous flossing and/or cleaning.

[0005] The concept of the use of dental floss for cleansing interproximal spaces appears to have been introduced by Parmly in 1819. Parmly suggested the use of waxed silk to clean teeth of persons subject to gingival inflammation.

[0006] The role of plaque, now described as subgingival biofilm, in gum disease is well documented. The need to physically remove subgingival biofilms routinely has become an accepted treatment for gum disease. Mechanical removal of subgingival biofilms can be achieved professionally through: scaling, planing, prophylaxis and polishing, and individually by tooth brushing, proxy brushing and flossing.

[0007] While these methods of physically removing subgingival biofilms from tooth surfaces are effective and well accepted; gum disease continues to be prevalent in the adult population, and consequently, improved means for the individual to physically remove subgingival biofilms routinely are indicated.

[0008] Furthermore, the spacing between teeth is not uniform and it varies considerably, not only from one place to another between the same pair of teeth, but also from one pair of teeth to another pair of teeth. The spacing varies in the same individual, among different individuals, and especially in the case of twisted teeth and teeth that have fillings, crowns, etc.

[0009] To accommodate tight spacing and those interproximal contacts that do not allow multifilament dental floss to be worked between teeth without fraying, breaking, etc., a vast array of “TEFLON” dental flosses have been commercialized. These shred-resistant, monofilament tapes are described in detail in the following U.S. patents, which are hereby incorporated by reference: U.S. Pat. Nos. 3,664,915; 3,953,566; 3,962,153; 4,096,227; 4,187,390; 4,256,806; 4,385,093; 4,478,665; 4,776,358; 5,033,488; 5,209,251; 5,220,932; 5,518,012; 5,718,251; 5,765,576; and 5,911,228.

[0010] The TEFLON-type tapes available commercially in the marketplace today, include: Gore's Glide®, Oral-Bs Satin Floss®, Johnson & Johnson's Easy Slide®, and Colgate's Total®). All of these tapes can be worked between tight spaces with a minimum of fraying and breaking. Yet, unlike their multifilament counterparts such as Johnson & Johnson's woven floss, REACH®Gentle Gum Care, during flossing, these tapes do not release substantial quantities of cleaners, abrasives, tartar control ingredients, whiteners and active ingredients such as fluoride, antimicrobials, antibiotics, etc. The net of this shorting in failing to deliver substantial quantities of ingredients to those sites being flossed is that the tapes are generally perceived as most convenient fitting between teeth, but unfortunately, they are generally perceived as: “not cleaning”, “not working”, “not doing much”, etc., once they are positioned between teeth.

[0011] When substantial quantities of cleaning, conditioning and treating substances are coated onto tapes, the resultant tapes are characterized by excessive flaking and breaking off of these coatings during processing, dispensing and wrapping of tape around the fingers. As a result, there are no commercial tapes available with substantial coatings of releasable ingredients suitable for working into and physically removing biofilms from interproximal and subgingival spaces.

[0012] Biofilms are notorious throughout nature for being difficult to remove. Working a monofilament tape over biofilms in the absence of substantial quantities of cleaners, abrasives, etc., is not effective in physically removing and/or disrupting substantial quantities of biofilms. The net is, critical biofilm buildup interproximally and subgingivally cannot be effectively physically removed with routine flossing with current commercial dental tapes, both PTFE tapes and bicomponent tapes.

[0013] Monofilament interproximal devices are described and claimed in: U.S. Pat. Nos. Re 35,439; 3,800,812; 4,974,615; 5,760,117; 5,433,226; 5,479,952; 5,503,842; 5,755,243; 5,845,652; 5,884,639; 5,918,609; 5,962,572; 5,998,431; 6,003,525; 6,083,208; 6,148,830; 6,161,555; and 6,027,592, the disclosures of which are hereby incorporated herein by reference. These dental tapes generally have serious shortcomings in gentleness, in delivering coatings during flossing and in being handled easily and conveniently during flossing.

[0014] Polytetrafluoroethylene (PTFE) based interproximal devices are described in: U.S. Pat. Nos. 5,209,251; 5,033,488; 5,518,012; 5,911,228; 5,220,932; 4,776,358; 5,718,251; 5,848,600; 5,787,758; and 5,765,576. To date, no commercial versions of these tapes have been coated effectively and cannot be used to deliver active ingredients, interproximally and subgingivally during flossing. Handling during flossing is difficult. Most have to provide a consumer acceptable edge. Many are plagued with serious dimensional inconsistency problems, as well.

[0015] Several patent applications have been filed on monofilament dental tapes with coatings comprising from between about 20% by weight and about 120% by weight of the monofilament tape. These are described in copending U.S. Provisional Patent Application Serial Nos. 60/227,433 and 60/227,255, filed Aug. 23, 2000 and Ser. No. 60/263,220, filed Jan. 22, 2001, all of which are hereby incorporated by reference.

[0016] There is clearly a need for a commercial, shred-resistant tape that is coated with releasable ingredients that help disrupt and/or physically remove biofilms from critical interproximal and subgingival sites when used regularly, and deliver chemotherapeutic agents as required in a site-specific manner.

[0017] The present invention centers around the observation that the substantivity of coatings onto flexible surfaces, including dental tapes, can be enhanced such that during flexure of the surface, these enhanced coatings remain substantive to said surface and resist cracking, fracturing and flaking off. Specifically, it has been observed that most coated flexible surfaces, especially those formulated to be saliva-soluble and carry effective quantities of abrasives, cleaners, surfactants, and chemotherapeutic agents, fracture along crystal faces during flexure, thereafter releasing the ingredients from the flexible surface by cracking, chipping, flaking and/or falling off etc. In response to these observations, it has been unexpectedly found that the addition of certain substances to various coatings at relatively modest levels reduces crystal formation while simultaneously enhancing the coating's substantivity to flexible surfaces subjected to flexure, which properties thereby impart outstanding flake resistance and release value to said tape.

[0018] Those coating additives that reduce, control and/or eliminate crystal formation and enhance the substantivity of the coating to flexible surfaces when added to these coatings at modest levels include certain aliphatic, long chain, fatty alcohols having from between about 10 and 30 carbon atoms and/or various liquid surfactants such as polyethylene glycol sorbitan dialiphatic esters.

[0019] Suitable aliphatic, long chain, fatty alcohols for the crystal-free coatings of the present invention can be represented by the structural formula ROH, wherein R represents a long chain alkyl group having from 20 to 30 carbon atoms. Specific examples include:

[0020] Naturally occurring mixtures with substantial quantifies of these fatty alcohols, or isomers thereof; including those chemically derived from natural sources also constitute suitable sources of aliphatic, long chain fatty alcohols for the purpose of this invention.

[0021] The long chain fatty alcohols can be represented by the structural formula ROH wherein R represents a long chain alkyl group having from 10 to 30 carbon atoms. These can be purchased commercially from Stepan, Proctor & Gamble and Aldrich Chemical Co. and a variety of companies processing vegetable and animal derived fatty alcohols.

[0022] Suitable liquid surfactants for the crystal-free coatings of the present invention include polyoxyethylene glycol sorbitan mono- and di-aliphatic esters represented by the general formula:

[0023] wherein R₁, R₂, R₃, R₄are H or aliphatic acyl groups from (10 to 30) and the sum of w, x, y, and z is from between 20 and 80. These liquid surfactants are available under the trade names Emsorb®, Span®, Tween® from Cognis N.A. and ICI. Specific examples of these include:

[0024] PEG 20 sorbitan monooleate (Tween® 80, ICI);

[0025] PEG 40 sorbitan monostearate (Span 60®, ICI); and

[0026] PEG 40 sorbitan diisostearate (Emsorb® 2726, Cognis, N.A.).

[0027] Similar esterified, PEG-based surfactants, which are known to those having ordinary skilled in the art, are also suitable liquid surfactants.

[0028] One preferred embodiment of this invention thus comprises substantive coatings for flexible surfaces that, under flexure, resist cracking, flaking, breaking off, etc.

[0029] Another preferred embodiment of the present invention comprises a shred-resistant dental tape that physically removes biofilms from interproximal and subgingival sites.

[0030] Another preferred embodiment of the invention comprises a method of applying substantive coatings of biofilm disrupting substances to shred-resistant tapes which coatings are released onto and worked into biofilms during flossing.

[0031] A further preferred embodiment of the invention comprises shred-resistant tapes with substantive coatings that exhibit minimum flaking, yet achieve total release during flossing.

[0032] Yet another preferred embodiment of the invention comprises monofilament tapes with substantially crystal-free coatings that are substantive, saliva soluble and exhibit with a minimum of flaking.

[0033] Still another preferred embodiment of the invention comprises a shred-resistant dental tape with a substantive coating that helps physically remove biofilms when released from the tape during flossing.

[0034] A further preferred embodiment of the present invention comprises substantive coatings for dental tapes that contain biofilm disrupting and physically removing ingredients along with biologically active or chemotherapeutic ingredients, all of which are largely or totally released during flossing.

[0035] Still another preferred embodiment of the present invention comprises a method for treating interproximal and subgingival sites to remove subgingival and interproximal biofilms while treating said sites with active ingredients.

[0036] Yet another preferred embodiment of the invention comprises a method for manufacturing a shred-resistant dental tape that contains substantial levels of biofilm disrupting/removing ingredients that do not flake off; yet are totally releasable during flossing.

[0037] Another preferred embodiment of the invention comprises coated dental tapes with a flaking value of less than about 20.

[0038] A further preferred embodiment of the invention comprises a class of coated dental tapes with coating release values approaching about 100.

[0039] These and other embodiments of the invention are described in detail below.

[0040] For the purposes of the present invention, “crystal-free” is defined as a smooth surface as distinguished from rough surface typical of crystalline coatings when observed through a 30× stereo zoom microscope.

[0041] For the purposes of the present invention, flaking resistance measures the propensity of the coatings of the present invention to flake off a flexible elastomeric, TEFLON®, bicomponent or other polymeric dental tapes during flexure. flaking resistance (or “flake value”) is a percentage value based on the reduction by weight of the crystal-free coating alter flexing, under suitably controlled and reproducible conditions, an 18-inch piece of the coated tape for 30 seconds.

[0042] For the purposes of the present invention, release value is measured after 18-inches of the tape is thoroughly flossed for 60 seconds. The percent of the crystal-free coating removed from the tape during flossing establishes the release value.

[0043] For the purposes of the present invention, dental tape is defined as monofilament tapes including elastomeric tapes such as Perident's Fibaclean™, PTFE tapes, such as Gore's Glide®, J&J's Easy Slide® and Colgate's Total® and bicomponent tapes such as Oral-B's Satin Tape®.

[0044] Certain petroleum waxes are suitable and preferred traditional additives for the crystal-free coating of the present invention. These include any of a range of relatively high molecular weight hydrocarbons (approximately C₁₆to C₅₀), solid at room temperature, derived from the higher-boiling petroleum fractions. There are three basic categories of petroleum wax; paraffin (crystalline), microcrystalline, and petroleum. Paraffin waxes are produced from the lighter lube oil distillates, generally by chilling the oil and filtering the crystallized wax they have a melting point range between 48° C. (118° F.) and 71° C. (160° F), Fully refined paraffin waxes are dry, hard, and capable of imparting good gloss. Microcrystalline waxes are produced from heavier lube distillates arid residue (one bottoms) usually by a combination of solvent dilution and chilling. They differ from paraffin waxes in having poorly defined crystalline structure, darker color, higher viscosity, and higher melting points ranging from 63° C. (148° F.) to 93° C. (200° F.). The microcrystalline grades also vary much more widely than paraffins in their physical characteristics: some are ductile and others are brittle or crumble easily.

[0045] Petrolatum is derived from heavy residual lube stock by propane dilution and filtering or centrifuging. It is microcrystalline in character and semi-solid at room temperature. There are also heavier grades for industrial applications, such as corrosion preventives, carbon paper, and butcher's wrap. Traditionally, the terms slack wax, scale wax and refined wax were used to indicate limitations on oil content. Today, these classifications are less exact in their meanings, especially in the distinction between slack wax and scale wax. Natural waxes such as beeswax and carnauba wax are also suitable and may provide specifically desired properties.

[0046] Suitable additional ingredients in the crystal-free coating of the present invention include anti-plaque ingredients˜such as MICRODENT® and ULTRAMULSION^™as described in various U.S. patents to Hill, et al., including U.S. Pat. Nos. 4,911,927; 4,950,479; 5,032,387; 5,098,711; 5,165,913; 5,538,667; 5,561,959; 5,66,374 and 5,733,529. The foregoing are incorporated herein by reference.

[0047] Various other active ingredients can be included in the substantive saliva-soluble coatings applied to the various dental tapes of the present invention including antimicrobial, anti-tartar, whitening, cleaning, desensitizing, antibiotic, anti-inflammatory, anti-gingivitis ingredients, as well as prostaglandin (PGE₂) and C-reactive protein control substances.

[0048] Specific active ingredients suitable for use in the coated dental tape of the present invention include: fluoride, potassium nitrate, triclosan, chlorhexidine, cetylpyridinium chlorhexidine, domaphen bromide, metronidazole, doxycycline, aspirin, the essential oils in Listerine®, and mixtures thereof.

[0049] The substantial coatings for the dental tapes of the present invention can be further characterized as: (a) containing a crystal control substance, (b) being saliva soluble, (c) substantially crystal-free, and (d) comprising from between about 20% and 120% by weight of said tape, and having a flake value of less than about 20 and a release value of about 100.

[0050] Elastomeric dental tapes such as described in the referenced co-pending applications coated with the crystal-free coatings of the present invention are described in Table I below.

[0051] The present invention has been described in detail, including the preferred 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 invention as set forth in the following claims.