WO1987005501A1

WO1987005501A1 - Treatment of dental surfaces with plaque retardants

Info

Publication number: WO1987005501A1
Application number: PCT/US1987/000553
Authority: WO
Inventors: Robert L. Goldemberg
Original assignee: Oral Research Laboratories, Inc.
Priority date: 1986-03-17
Filing date: 1987-03-16
Publication date: 1987-09-24
Also published as: AU7204787A

Abstract

Oral compositions for dental hygiene, and, in particular to dental rinse formulations comprising substantive biocides capable of adhering or adsorbing onto dental surfaces, oral surfactants and detergent builders. These compositions, upon application to the teeth, loosen plaque present on dental surfaces, rendering the plaque more amenable to removal during brushing with a conventional dentifrice.

Description

TREATMENT OF DENTAL SURFACES WITH PLAQUE RETARDANTS

FIELD OF THE INVENTION

This invention relates to improved oral compositions for retarding and loosening plaque, reducing stain area or intensity, and contributing to improved oral hygene, and, in particular, to anti-plaque dental rinse formulations which upon use in the oral cavity make more practicable both the simultaneous use of pharmacologically acceptable substantive biocides which act as potent anti-plaque agents, and the use of such biocides in close time proximity to (i.e. soon before or soon after) use of the anti-plaque dental rinse formulations. The invention further relates to formulations which loosen plaque present on dental surfaces and render plaque more amenable to removal during brushing with a conventional dentifrice, or during other conventional oral hygiene practices, and to methods of plaque control and stain reduction.

BACKGROUND OF THE INVENTION

Dental plaque is present to some degree, in the form of a film, on virtually all dental surfaces. It is a by¬ product of microbial growth, and comprises a dense microbial layer consisting of a mass of microorganisms embedded in a polysaccharide matrix. The microorganisms present in plaque are mainly coccoidal organisms, particularly in early plaque, which, in the mouths of some persons at least, change to filamentous organisms after a few days. Plaque itself adheres firmly to dental surfaces and is removed only with difficulty even through a rigorous brushing regimen. Moreover, plaque rapidly reforms on the tooth surface after it is removed.

A wide variety of microorganisms are found in the oral cavity, and among these are gram-positive anaerobic rods associated with the development of plaque such as Corvnebacterium, Nocardia, Neisseria and Streptococci , such as S. mutens, S. bovis, S. salivarius, and gram- positive streptococci of the genus Peptostreptooccus (See Robert J. Fitzgerald in "The Alabama Journal of Medical Sciences" Volume 5, No. 3, July, 1968, pp. 241- 242) .

In addition to the aforementioned microorganisms, there is also present in plaque relatively small amounts of other substances such as salivary proteins, carbohydrates, epithelial cells and leucocytes. The organisms play a key role in the etiology of plaque. The bacterial organisms associated with plaque formation produce a capsular material which apparently causes the cells of the organism to adhere to each other, holding the plaque together and allowing for further growth. For example, one of the capsule forming bacteria which occurs in large numbers in early plaque is Neisseria sicca.

Plaque may form on any part of the tooth surfaces, and is found particularly at the gingival margin, in cracks in the enamel, and on the surface of dental calculus. As discussed in greater detail below, the danger associated with the formation of plaque on the teeth lies in the tendency of plaque to build up and eventually produce gingivitis, periodontitis and other types of periodontal disease, as well as dental caries and dental calculus.

More specifically, dental plaque is a precursor to the formation of the hard crystalline buildup on teeth referred to as dental calculus. Both the bacterial and the nonbacterial components of plaque mineralize to form calculus, which comprises mineralized bacteria as well as organic constituents, such as epithelial cells, live bacteria, salivary proteins, leucocytes, and crystals of substances having molecularly bound calcium and phosphorus, e.g., hydroxyapatite, 3[Ca₃(P0₄)_]Ca(OH) - , octacalcium phosphate, Ca_(HP0₄)₂(P0₄)..5H₂0, brushite, CaHP0₄.-H₂0, and whitlockite, which is considered to have the formula beta-Ca₃(P0₄)₂, Dental plaque and, hence, calculus are particularly prone to form at the gingival margin, i.e., the junction of the tooth and gingiva. The buildup of plaque at the gingival margin is believed to be the prime cause of gingivitis and other periodontal disorders.

Regular tooth brushing with a conventional dentifrice for some persons greatly retards or even prevents the accumulation of significant amounts of plaque and calculus. For other persons, however, plaque builds up rapidly even with regular brushing, which, in turn, leads to the formation of calculus, caries, and presents the danger of periodontal diseases. Removal, by a dentist is currently the only safeguard against serious gingival inflammation caused by the accumulation of significant amounts of plaque in some individuals. It is widely recognized in dentistry that a rigorous brushing regimen alone for many individuals will not prevent the formation of significant amounts of plaque. Mouthwashes are employed in conventional regimens of oral hygiene. However, conventional outhwashes serve primarily to sweeten the breath, are formulated for that purpose, and are believed not to function in any significant way to loosen or remove plaque from the dental surfaces. Moreover, since the user typically does not employ a mouthwash expressly for the purpose of cleansing the teeth of plaque, mouthwashes are not routinely used immediately prior to brushing as a way of rendering plaque and/or calculus more amenable to removal during the subsequent brushing process. Additionally, mouthwashes have not normally been used as effective stain removal formulations.

There is, therefore, a definite need in the art for an oral hygiene composition which renders the plaque present on the dental surface more susceptible to removal during a subsequent brushing regimen employing a conventional dentifrice.

Substantive biocidal agents are those which when topically applied to dental surfaces inhibit plaque buildup. For example, substantive biocidal agents useful herein may be attracted to the surface of plaque or to other surfaces of the oral cavity to provide a plaque-prevention effect for a time period after initial topical application of the biocide. For instance, Johnson et al. report in "A Review of Chemotherapeutic Plaque Control," ORAL SURG 47(2) :136-41 (Feb. 1979) that the biguanide chlorhexidine has been demonstrated to successfully control plaque. As is explained in greater detail below, the effectiveness of plaque inhibiting compositions can be enhanced by adding one or more substantive biocides in addition to any other biocides present in the formulation. Many substantive biocides can be compatible with mouthwash formulations and are effective in killing bacteria associated with plaque. However it is believed that certain substantive biocides can lead to discoloration of dental surfaces, and can be disfavored for use in oral hygiene because of this side effect. For example, such discoloration has been observed with respect to chlorhexidine. See Hull, P.S., "Chemical Inhibition of Plaque" I. Clin Periodontol. 7(6):431-42 (Dec. 1980).

It is an object of this invention to provide improved dental compositions containing biocides and/or substantive biocides which function to retard the buildup of plaque on the dental surfaces, and which also function to loosen the plaque present on dental surfaces, and to thereby make plaque amenable to removal by tooth brushing, all without producing objectionable discoloration on the dental surfaces to which the composition is applied.

Other objects and advantages of the present invention will become apparent to one of skill in the art from a reading of the specification of this application.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the foregoing, this invention provides dental hygiene compositions for loosening the adherence of plaque present on teeth, retarding the further accumulation of plaque on the treated surfaces, and allowing use of substantive biocidal compositions without discoloration or staining. As is explained below, the compositions of the invention comprise a dental rinse solution effective for loosening plaque which contains detersive amounts of an oral surfactant in combination with an orally compatible benzoic acid salt or derivative thereof, wherein the foregoing plaque-loosening composition includes a substantive biocide in an amount effective to retard the buildup of plaque .

Preferred substantive biocides for use in the foregoing compositions include, for instance, chlorhexidine, its derivatives, and pharmacologically acceptable salts or esters thereof such as l,l'-hexamethylene bis -[5-(4- chlorophenyl) biguanide] digluconate.

These or other substantive biocides may be added directly to the formulation before use or, alternatively, the substantive biocide may be excluded from the plaque loosening formulation and instead employed as part of separate formulation. For example a separate chlorhexidine dental rinse formulation may be comprised of a solvent, preferably an aqueous solvent comprising about 0.005 to about 0.50 percent chlorhexidine by weight, and further may include other known agents for improving the mouthfeel, taste and other properties of the formulation. For instance, flavoring and wetting agents may be added.

It is believed that the plaque loosening properties of the dental rinse described herein may well serve to reduce the tendency of certain substantive biocides such as chlorhexidine to stain dental surfaces. While not wishing to be bound by theory, it may be that chlorhexidine staining is caused by the action of chlorhexidine on the plaque thereby staining the plaque and not by action on the natural white enamel of teeth. Thus, when chlorhexidine or other substantive biocides are used in conjunction with the plaque loosening and removing dental rinse disclosed herein, staining should be eliminated or at least reduced since less plaque should be available for any staining which might otherwise be caused by the substantive biocide. Thus, the rinse described herein may well render more desirable the use of particularly potent substantive biocides whose use has not been widespread because of their tendency to cause staining on dental surfaces.

In preferred embodiments, the dental rinse of this invention comprises at least about 1%, and most preferably at least about 2% by weight of an orally compatible benzoic acid salt or ester, preferably sodium benzoate. It has been found that when sodium benzoate is employed in the dental composition described above, the ability of the formulation to loosen plaque and to prevent plaque buildup subsequent to the application of the dental composition is unexpectedly and significantly enhanced. It is also preferred to employ a detergent building component in the formulation.

In further embodiments of the dental compositions of this invention, minor effective amounts of colorant, flavorant, antiseptics, healing agents and other additives are advantageously employed in combination with the other ingredients. More specifically, formulations of the dental composition of this invention may include antiseptically effective amounts of sodium salicylate, ethanol (which may also serve as all or part of the liquid carrier), and an antiseptically active flavorant, e.g., thymol/eucalyptol menthol. Of course, sodium benzoate itself imparts antiseptic properties to the formulation. Formulations, containing the foregoing ingredients, serve to soothe gums irritated from brushing, and when healing agents are employed, to actually enhance the rate of healing of gums and associated tissues which may have become irritated during brushing or due to an existing periodontal disorder such as gingivitis.

The pH of the compositions may be adjusted to optimize the effectiveness of certain components of the rinse. In one embodiment of the present invention, a pH above the pKa of benzoic acid is employed. For example, an alkaline pH of above about 7.0, i.e., 7.0 to about 9.5 may be employed. On the other hand, it is also desirable to adjust the overall pH to maximize the efficacy of the given substantive biocide selected for use, while at the same time ensuring that plaque loosening properties of the composition are maintained, and the solubility of the components is maintained, etc. For instance, when chlorhexidine is used as the substantive biocide, it is believed that the plaque- retarding efficacy of the chlorhexidine can be achieved by adjusting the pH of the overall formulation to between about 5.7 to about 6.6. However, when chlorhexidine is employed, the overall pH is preferably above about 6.0, most preferably above about 6.3 to about 6.6.

This invention also provides a method for loosening plaque from dental surfaces which comprises the step of applying the dental rinse composition described above to the dental surfaces of the oral cavity. By repetitive or regular use the dental rinse of this invention will retard plaque build-up. In preferred embodiments of the method of this invention, the rinse is applied to the dental surfaces in conjunction with a conventional tooth brushing or oral hygiene regimen. It is believed that the dental rinse of this invention renders the plaque present on dental surfaces quite susceptible to subsequent removal during an ordinary brushing process. The invention also provides a method for reducing stains on dental surfaces by applying dental hygiene compositions comprised of detersive amounts of an oral surfactant and a pharmacologically acceptable benzoic acid salt or ester or derivatives thereof.

Compositions of the invention may be applied to the surface of the teeth by any conventional process. Preferably, however, the dental rinse is applied by placing a comfortable amount of the dental rinse in the oral cavity and then circulating the rinse about the mouth with the intention of thoroughly soaking the teeth and gums.

The dramatic reduction in plaque content accomplished through the use of the dental rinse and associated methods of this invention should also serve both to reduce dental caries closely associated with plaque buildup, as well as preventing or ameliorating plaque and plaque-associated oral disorders such as gingivitis and periodontitis.

Further advantages and objects of this invention will be apparent from the detailed description of the invention which follows.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

Preferred dental rinses of this invention comprise one or more substantive biocides in an amount effective to retard plaque buildup; preferably chlorhexidine in the form of chlorhexidine gluconate is present in a concentration of about 0.005 and 0.500 percent by weight of the composition and most preferably about 0.05 to about 0.20 percent. In addition to the chlorhexidine or other substantive biocide the dental rinse comprises detersive amounts of an oral surfactant, as well as amounts of a benzoic acid salt or a derivative thereof which is effective to loosen plaque in combination with the oral surfactant. The active ingredients are dissolved within a liquid carrier. Preferred liquid carriers include water and a solution of water and alcohol (ethanol). The preferred liquid carrier may comprise from about 70% to about 95% of the formulation. The formulation may include as the liquid carrier a component of about 65% to 95% water and about 5% to 35% ethanol.

Pharmacologically acceptable substantive biocides may be employed in the dental rinse. In general, the bis- biguanide biocides as a class are very useful as the substantive biocides. It is believed that certain substantive biocides are especially effective to inhibit - the buildup of plaque because of their ability to physically be adsorbed onto or "stick" to plaque colonies and thus act upon them longer than biocides which are easily washed away. Substantive biocides also stick to other dental surfaces from which they are washed away gradually such that they continue to retard plaque growth for a time period after the original application.

Chlorhexidine, its structural analogs and salts and esters thereof, are especially preferred. Other useful substantive biocides include alexidines, l,6-di-(2- ethylhexyl diguanide) hexane compounds; octinidines, l,10-bis[4-(octylamino)-l-pyridinium] decane compounds and structural analogs of alexidines and octinidines. These compounds would normally be added to the formulation in the form of a salt or ester. Octinidine hydrochloride is a preferred octinidine. Cationic biocides can be effective substantive biocides.

Substantive biocides may be provided either directly within the plaque-removing and loosening rinse of this invention or as part of a separate rinse, or both. When chlorhexidine is used as the substantive biocide for instance, it is preferably added in the form of chlorhexidine gluconate and represents from about 0.005 to about 0.500, most preferably about 0.05 to about 0.20 percent by weight of the dental rinse, e.g., above about 0.100 percent by weight of the dental rinse formulation. -li¬ lt may be added directly to the plaque loosening dental rinse, or alternatively, dilute chlorhexidine solutions may be used in a separate rinse in close time proximity to (e.g. soon before or after) use of the above- described rinse. In accordance with this alternative embodiment, chlorhexidine need not be present in both rinses, but it may be if desired.

The oral surfactants employed in the dental rinse of this invention are those surfactants which are nontoxic and therefore suitable for use in the oral cavity, and which provide a detersive effect when the formulation containing them is applied in about tablespoon quantities to the oral cavity. As explained below, it is preferable to employ a detergent builder in conjunction with the oral surfactant, most preferably one of the benzoic acid salts referred to above. The nonionic oral surfactants are preferred for use as the oral surfactant component, although suitable anionic and cationic surfactants may also be employed.

Nonionic oral surfactants which may be employed herein include mixtures of laurate esters of sorbitol and sorbitol anhydrides consisting predominantly of the monoester condensed with about 15 to 25 (e.g. 20) moles of ethylene oxide, such as the commonly available nonionic detergent Tween 20 available from I.C.I. Americas, Wilmington, Delaware; as well as the block polymers of polypxyethylene and polyoxypropylene, such as Pluronic F108 available from BASF-Wyandotte Co., Wyandotte, Michigan. In addition, suitable oral surfactants for use herein include alkyl sulfonates and sulfates such as sodium lauryl sulfate or a sulfonated monoglyceride of a fatty acid having about 10 to about 18 carbon atoms, as well as N-methyl-N-palmitoyl tauride, sodium-N-lauroyl sarcosinate, other sarcosinates, sulfosuccinates, or the like. The oral surfactant is preferably employed in the aqueous or ethanolic solvent of the dental rinse at levels ranging from about .1% to about 10% by weight of the composition, and most preferably from about .5% to about 2% of the composition. However, in general, the amount of nonionic detergent employed is adjusted to provide the desired degree of detersive effect or, if desired, foam in the oral cavity during use.

Alkaline alkyl sulfates, especially where the longest chain of the alkyl portion ranges from 9 to 15 carbon atoms, when added in concentrations from 0.1% to 1.5% are especially desirable. Dental rinses formed with these oral surfactants display a number of desired characteristics. For instance, when sodium lauryl sulfate is added at a concentration from 0.1% to 1.5%, plaque removal on initial use is high, and unremoved plaque exhibits markedly decreased viability and markedly increased susceptibility to removal by simple mechanical methods. The pH drop that usually occurs shortly after using a rinse is effectively delayed, indicating that production of acid by unremoved plaque has been substantially halted. Furthermore, a rinse formulated with sodium lauryl sulfate is effective at a much greater dilution than is a rinse formulated without such an alkaline alkyl sulfate. It is believed, without limitation, that sodium lauryl sulfate acts as a potentiator for other ingredients of the rinse, thereby increasing their ability to loosen plaque, and their ability to penetrate bacterial colonies. A rinse having the surfactants described above is appropriate for combination with substantive biocides in accordance with Applicant's teachings.

A detergent builder may be employed in combination with the oral surfactant component of the dental rinse. The detergent builders employed herein include nontoxic. orally compatible materials which are distinctly basic in aqueous solution, for example, sodium carbonate, sodium borate, mixtures thereof, or alkaline mixtures of sodium carbonate and/or sodium borate with sodium bicarbonate. Preferably, the detergent builder is sodium borate and is present in amounts ranging from about .1% to about 1%, and most preferably, .2% to about .5% by weight of the rinse formulation. However, most preferably the detergent builder is an orally compatible benzoic acid salt or derivative thereof. Combinations of such a benzoic acid or derivative are advantageously employed in combination with other builders. It is believed that the use of a detergent builder in conjunction with the surfactant component of this invention in basic solution enhances the ability of the dental rinse to both loosen and dislodge plaque from dental surfaces during rinsing, while at the same time enhancing the ability of the rinse to maintain the loosened plaque or calculus materials in suspension in the rinse, enabling the user to finally discharge them from the mouth. Significantly, the plaque-loosening effect of the rinse renders the plaque remaining on the dental surface far more amenable to removal during a subsequent brushing process.

When the dental rinse is distinctly basic, as will be the case when sodium borate is employed, sodium bicarbonate is advantageously employed in combination with sodium borate, both for its detergent building properties, as well as for its buffering properties in an aqueous solution. In particular, an amount of sodium bicarbonate may be employed in an aqueous ethanolic, or aqueous/ethanolic solvent base containing one or more distinctly basic ingredients (e.g., sodium borate) in order to adjust the dental rinse to the desired basic pH level discussed above. For example, when sodium borate is employed in the amounts stated above, sodium bicarbonate is preferably employed at levels ranging from about .1% to about 1.5%, and most preferably about .3% to about 1.0% by weight of the rinse formulation.

The pH of the dental rinse may be adjusted to preferred levels by use of buffers or by other known methods. The upper limit of the pH of the composition is limited, however, by the possible irritative effects of strongly alkaline solutions in the oral cavity. Thus, the pH is preferably not above 10.0.

It has been found that when sodium benzoate is employed in combination with the other ingredients of the dental rinse of this invention, the plaque loosening and retarding properties of the composition are significantly enhanced. Thus, in a preferred embodiment of this invention, the dental rinse comprises an alkaline solution having a pH of at least about 7.5, of a liquid solvent carrier selected from the group consisting of water, ethanol or mixtures thereof containing sodium borate, an oral surfactant, and sodium benzoate. Sodium benzoate is employed at a level of a least about 1% by weight, and most preferably at least about 2% by weight of the composition.

Plaque consists of about 80% live bacteria in a polysaccharide matrix. Therefore, it is desirable for a dental rinse to possess significant antibacterial properties in order to eliminate or retard the growth of the bacterial colonies present in plaque. Bactericides and biocides other than substantive biocides can be beneficial. For instance, the relatively high levels of sodium benzoate employed in embodiments of this invention impart additional antiseptic properties to the formulation over and beyond those imparted by substantive biocides. Moreover, in order to advantageously enhance the antiseptic properties of the dental rinse, other auxiliary antiseptics may be included in the formulations. Further, antiseptic properties may also be imparted to the dental rinse by the use of a liquid carrier comprised of ethanol or ethanol/water, and/or auxiliary antiseptics suitable for use in the oral cavity.

A preferred antibacterial (and analgesic) compound which can be added in addition to substantive biocides is sodium salicylate. It is believed that sodium salicylate is advantageously employed in the dental rinse formulation of this invention because it also functions to aid in the solubilization and removal of plaque from the dental surface. In addition to, or in place of sodium salicylate, other oral antiseptics which are soluble in the liquid carrier (i.e., water and/or alcohol) and which are compatible with other ingredients of the formulation may be employed, for example, benzethonium chloride, N-alkyl-pyridinium chloride, N- cetyl pyridinium bromide, sodium N-lauroyl sarcosine, N-myristoyl glycine and potassium N-lauroyl sarcosine. The sodium salicylate or other analgesics preferably comprise about .1 to 1%, and most preferably, about .2 to about .5% by weight of the rinse.

In addition to the foregoing ingredients, the dental rinse of this invention may include adjuvant ingredients effective to provide the desirable flavoring and coloring, and to impart the desired mouthfeel to the formulation. In further embodiments of this dental rinse, the flavorant employed is one which possesses antiseptic properties, e.g. a flavorant based upon thymol, eucalyptol and menthol. Thus, the formulation may include as combined antiseptic ingredients sodium benzoate, sodium salicylate and the above-mentioned antiseptic flavorant or an equivalent antiseptic flavorant. The concentration of the flavorant is adjusted to impart the desired taste and/or degree of antibacterial activity to the overall formulation.

In further embodiments of the dental rinse formulation of this invention, effective amounts of one or more analgesics and/or substances which promote wound healing, i.e., healing agents, are employed. To this end, sodium salicylate discussed above is particularly preferred because of its associated antiseptic and plaque solubilizing properties. The healing agent may be suitably employed at levels of, for example, .1 to about 3%. The preferred healing agent for use herein is allantoin (glyoxyl diuride).

In particular, a combination of a soluble hydrocolloid (e.g. xanthan gum), sodium salicylate and allantoin is advantageously employed for its combined wound healing analgesic properties. That combination of ingredients provides both a soothing effect to gums that may be irritated following brushing, and additionally may enhance the rate of gum-healing due to the debriding and healing action of the allantoin. Sodium bicarbonate also promotes debridement and, hence, it is advantageously employed in the formulation of this invention for that purpose, as well as for the other reasons discussed above.

The dental rinse of this invention may also contain ingredients such as glycerine in amounts up to about 20% by weight, or, for example, about 8% to 18% by weight. The glycerine functions as a sweetener, and also imparts body to the composition (along with the alcohol or any gums present) as well as the desired mouthfeel. Equivalent materials may be employed in place of, or in combination with, the glycerine such as sorbitol and/or propylene glycol. The dental rinse is prepared by mixing the active ingredients together to form a homogeneous solution of the constituent ingredients. The rinse is used in a conventional manner: that is, by applying a comfortable amount in the mouth, say one tablespoon full, and rinsing it about the dental surfaces. As illustrated by the appended examples, a striking reduction in the amount of plaque on tooth surfaces is accomplished over a relatively brief usage period when the dental rinse of this invention is employed in conjunction with an ordinary tooth brushing regimen.

The manner of making and using the present invention will be illustrated further by the following detailed examples.

EXAMPLE 1

The following dental rinse was formulated:

Weiqht- Percent Component

Portion A- -1

15. .50 glycerine, USP

0. .8 01% FDC Red 40

72, .82 water

Portion A- -2

0, .03 xanthan gum

0. .20 allantoin

0. .20 sodium salicylate

Portion A- -3

00.. ,5500 sodium bicarbonate, USP

0. ,20 sodium borate, USP

2. ,00 sodium benzoate, NF

Portion B

6. ,60 ethanol

00.. ,3311 flavor compound

(4483T, Carruba Inc.)

0. ,84 Polysorbate 20

100. ,00%

A dry mix of the portion A-2 ingredients was prepared, and then slowly added to a mixture of the portion A-l ingredients with high-speed propeller agitation. Also under high-speed agitation, the phase A-3 ingredients were individually added in the listed order, followed by the slow addition of a previously prepared mixture of Portion B to the phase A 1-3 mixture. The resultant dental rinse had a pleasing red appearance and an acceptable mouthfeel. The product was uniform in appearance and did not separate even after prolonged standing at room temperature. The pH of the dental rinse was 7.7. EXAMPLE 2

Four patients were administered the dental rinse of Example 1, and were instructed to use the rinse as follows:

a. Use one tablespoon of the dental rinse before each brushing. Rinse vigorously around the mouth for 30 seconds.

b. follow immediately with the usual brushing routine (toothbrush plus toothpaste), brushing thoroughly.

c. repeat steps (a) and (b) twice daily.

All four test patients were examined prior to usage of the dental rinse ("Day 1" on chart below). Plaque area was monitored during the test period through the use of POH disclosing tablets in accordance with the standard Quigley & Hein Index. See G. A. Quigley and J. W. Hein, Comparative Cleaning Efficiency of Manual and Powered Brushing, J.Amer.Dent.Assn. , Vol. 65:26 (1962).

Gingival inflammation was measured by the Loe & Silness Index (See, Journal of Periodontology, Vol. 36, pg. 178 (1965), Loe, Theilades, Jensen), employing the Ranfjord Index which uses 6 teeth, numbers 3, 9, 12, 19, 25 and 28. The results are summarized in Table 1. TABLE 1

Patient Area of Plaque % Inflammation %

No. Day 1 Dav 8 Reduction Day 1 Dav 8 Reduction

1 2.38 1.60 33 1.67 1.21 28

2 2.75 1.77 36 1.58 1.25 21

3 1.44 1.00 31 0.95 0.63 34

4 2.29 1.43 38 1.04 0.54 48

The foregoing demonstrates that the dental rinse of this invention was an effective agent in significantly reducing both plaque and gingival inflammation over the test period, when used in a regular home dental care regimen.

EXAMPLE 3

The following formulations were prepared:

Ingredient Red Green Amber sorbitol (70% 15.50* 15.50 15.50 aqueous soln. ) sodium salicylate 0.20 0.20 0.20 sodium borate 0.20 0.20 0.20 sodium benzoate 2.00 2.00 - ethanol (95%) 6.95 6.95 6.95 flavor compound 4483T 0.31 - .31 peppermint oil - 0.15 - propylene glycol - 0.16 - polysorbate 20 0.84 0.84 0.84 water 73.20 73.75 75.95

1% FDC Red 40 0.80 — -

2% FDC Green 3 - 0.25

1% FDC Brown mixture - - 0.05

* Table values are given in weight percent on a composition basis.

A double blind study of the test formulations was conducted. (Neither the dentist administering the test nor the patients who used the dental formulations set forth above knew any details about the composition of the rinse).

Five patients were randomly chosen to use the red, five patients to use the green and five randomly chosen patients to test the amber formulation. At the start of the test each patient was given an initial examination with plaque disclosure tablets. The plaque disclosure tablets contained a red dye which preferentially stains plaque but does not stain the clean enamel surfaces of the teeth. The percent surface areas of the inside and outside tooth surfaces covered with plaque were then estimated, tooth by tooth, by a dentist in accordance with the method of Quigley & Hein, mentioned above.

After the initial examination, five patients were given a bottle of the red formulation, five patients were given the green, and five patients the amber formulation. Each patient was instructed to rinse with the formulation he was given twice a day prior to brushing. The patients were each instructed to retain the rinse in their mouths for at least 30 seconds, moving it around in the mouth in order to insure that all of the tooth and gum surfaces were well soaked in the rinse. After completing the rinsing step, the patient was instructed to brush in accordance with his regular routine and using his own toothpaste. After seven days of use of the test formulation, the patients returned to the clinic for a re-examination of their dental surfaces in accordance with the same procedures employed at the start of the test. The results of the test are summarized in Table 2. TABLE 2

Initial Score

Patient (befoi :e test) After 7 Days

Red Formula

#1 2.54* 0.96

#2 3.60 1.84

#3 2.86 0.54

#4 2.06 0.39

#5 3.73 0.45

Red Fc >rmula Averaαes 2.96 0.84

(72% reduiction)

Green Formula

#1 3.13 0.67

#2 2.82 0.71

#3 2.54 0.73

#4 3.14 0.00

Green Formul .a Averaqes 2.91 0.53

(82% rediiction)

Amber Formula

#1 1.19 1.04

#2 3.24 2.24

#3 2.70 3.20

#4 3.37 2.63

Amber Formula Averages 2.63 2.28 (13% reduction)

* Plaque scores are averages of front and back readings of all teeth in each patient's mouth.

The foregoing demonstrates the ability of the dental rinse of this invention to loosen, dislodge and retard the buildup of plaque when the dental rinse is employed prior to brushing. It is noted that even in test formulations which did not include sodium benzoate, plaque was reduced by 13% over the test period, while the effect was unexpectedly enhanced to 72% - 82% in the sodium benzoate containing formulations. EXAMPLE 4

A dental rinse can be formulated from the following components combined in the indicated weight percentages. Although the following formulation has not been tested for its ability to prevent staining by chlorhexidine, it is believed that such staining would be minimal.

Weiqht Percent Component

2. ,0 Sodium Benzoate, NF 0 0.. ,22 Sodium Salicylate, USP

0. ,5 Sodium Bicarbonate

0. ,2 Sodium Borate

0. ,8 FDC Red 40 (1% aq. )

0. ,5 Sodium Lauryl Sulfate, 94% 0 0.. ,88 Polysorbate 20

0. ,3 Flavor other than sodium saccharin

7. ,0 ethanol, 95%

72. ,58 water 1 155.. ,00 Glycerin, USP

0. ,02 sodium saccharin

0. ,10 Chlorhexidine gluconate

This invention has been described in terms of specific embodiments set forth in detail herein, but it should be understood that these are by way of illustration and the invention is not necessarily limited thereto. Modifications and variations will be apparent from the disclosure and may be resorted to without departing from the spirit of the invention as those of skill in the art will readily understand. Accordingly, such variations and modifications are considered to be within the purview and scope of the invention and the following claims.

Claims

WHAT IS CLAIMED IS:

1. A dental rinse composition for loosening and retarding the buildup of plaque on dental surfaces, comprising a solution containing an amount of a substantive biocide effective to retard the formation of plaque on dental surfaces, said composition further comprising at least about 1% by weight of said composition of a benzoic acid salt and detersive amounts of an oral surfactant; wherein said solution is effective when applied in rinsing fashion to dental surfaces to loosen plaque present on dental surfaces rendering it amenable to removal by brushing.

2. The composition of claim 1 wherein the substantive biocide is chlorhexidine, derivates of chlorhexidine or a pharmacologically acceptable salt or ester thereof.

3. The composition of claim 2 wherein the substantive biocide is chlorhexidine present in an amount between about 0.005 and 0.500% by weight of the composition.

4. The composition of claim 3 wherein the substantive biocide is chlorhexidine gluconate, said benzoic acid salt is sodium benzoate present in an amount of at least about 2% by weight of said composition.

5. The composition of claim 4 wherein said oral surfactant is sodium lauryl sulfate.

6. The composition of claim 1 wherein said substantive biocide is chlorhexidine gluconate which is present in an amount of above about 0.1% by weight of the composition.

7. The composition of claim 6 comprising at least about 2% by weight of the composition of a benzoic acid salt, and wherein said oral surfactant is sodium lauryl sulfate.

8. The composition of claim 1 wherein the substantive biocide is a bis-biguanide substantive biocide.

9. The dental composition of claim 1 wherein the substantive biocide is selected from the group consisting of chlorhexidine, alexidine, octinidine and pharmacologically acceptable salts, esters and analogs thereof.

10. The dental composition according to claim 1 wherein said surfactant comprises a sulfosuccinate, sarcosinate, or an alkyl sulfate salt, or mixtures of the foregoing.

11. The composition of claim 1 wherein the oral surfactant is sodium lauryl sulfate in an amount between about 0.1% and 10% by weight of the composition, said composition further includes sodium borate, and said composition comprises at least about 2% by weight of sodium benzoate.

12. The dental rinse according to claim 1 wherein said benzoic acid salt comprises at least about 2% by weight of said composition, and the pH of said solution is about 7.5 to about 9.0.

13. The composition of claim 1 further comprising about .1 to 1% by weight of sodium borate.

14. The composition of claim 1 further comprising minor effective amounts of an antiseptically active agent.

15. The composition according to claim 14 wherein said antiseptic is sodium salicylate, said composition also including sodium borate and sodium benzoate.

16. The composition according to claim 1 comprising by weight of said composition about .1 to about 10% of said oral ^• surfactant, about .1 to about 1% of sodium borate, and at -26- least about 2% by weight of sodium benzoate.

17. A method for loosening and retarding the buildup of plaque on dental surfaces comprising applying to the dental surfaces of the mouth an effective amount of the substantive biocide-containing dental rinse according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16.

18. The method according to claim 17 further comprising the step of removing plaque loosened by the application of said dental rinse said removal being accomplished by brushing the dental surfaces which had previously been contacted by said dental rinse.

19. The dental composition of claim 1 wherein the pH of the dental rinse is between about 7.0 and about 9.0.

20. A method for loosening and retarding the buildup of plaque on dental surfaces comprising applying two dental rinses to the dental surfaces wherein one of said rinses is comprised of an amount of a substantive biocide effective to inhibit the growth of plaque, and the other rinse is effective to loosen plaque on dental surfaces.

21. A dental rinse for retarding and reducing plaque buildup which comprises an effective amount of a substantive biocide selected from the group consisting of chlorhexidine, octinidine, alexidine, and the pharmacologically acceptable salts and esters thereof, an alkali alkyl sulfate surfactant, and in solution therewith a compound selected from the group consisting of sodium borate, sodium carbonate, sodium bicarbonate and mixtures of the foregoing, said dental rinse further comprising at least about 2% by weight of benzoic acid salt.

22. The dental rinse of claim 21 wherein the biocide is selected from the group consisting of chlorhexidine gluconate and octinidine hydrochloride, and the surfactant is sodium lauryl sulfate in an amount of from about 0.1% to about 1.5% by weight of the rinse.

23. The dental hygiene composition of claim 1 wherein the substantive biocides are selected from the group consisting of l,6-di-(2-ethylhexyl diguanido) hexane; l,10-bis(4-(octylamino)-l-pyridinium) decane;

1,1'hexamethylene bis-5-(4-chlorophenyl) biguanide; and pharmacologically acceptable salts and esters thereof.

24. A method of oral hygiene comprising periodic rinsing of the dental surfaces with a composition effective to loosen plaque present on dental surfaces, removing loosened plaque by brushing, and applying amounts of a substantive biocide to the dental surfaces effective to retard the formation of plaque on said dental surfaces.

25. The method of oral hygiene according to claim 24 wherein said composition effective to loosen plaque is comprised of an orally compatible solution of an oral surfactant and at least about 1% by weight of a benzoic acid salt.

26. The method of oral hygiene according to claim 25 wherein said oral surfactant is sodium lauryl sulfate.

27. The method according to claim 24 wherein said substantive biocide comprises chlorhexidine.

28. The dental rinse composition of claim 1 wherein the solution contains an amount of a substantive biocide effective to adhere or adsorb onto dental surfaces.