Gel Denture Cleanser Composition and Method of Application

The instant invention relates to a liquid cleanser composition comprising (a) a detergent selected from the group consisting of sulfated, sulfonated and sulfoacetate fatty alcohols; (b) a chelating agent of the amino carboxylate or organo phosphonate type; and (c) about 50% to about 94% water. The composition is designed to be delivered to the surface through a spray pump system or device. The inventive cleansers are particularly useful as denture cleansers.

The denture cleanser prior art has focused on the use of oxidizing agents and bleaching agents in concert to remove visible stain and scale or plaque buildup. For the most part these compositions have employed a variety of sulfate salts, e.g., bisulfates and monopersulfates, to serve as detergents and oxidizers, as well as alkali metal and alkali earth metal halides as bleaches. Perborate, carbonate, bicarbonate and phosphate salts were conventionally included to provide effervescence and activation. These references have focused on making powdered or tableted products which dissolve rapidly and effervesce when placed in water. These products clean dentures generally in 12-30 minutes or longer and require constant emersion during this period, followed by brushing and rinsing with water.

The persulfate and perborate systems of the prior art tend to discolor the stain on the denture. Tablets made from these ingredients were limited to small amounts of detergents or surfactants in order to achieve fast dissolution and subsequent cleansing when placed in water. Detergents of the high fatty alcohol type could therefore not be incorporated except in minute quantities, e.g., 1% or less, or poor tablet dissolution rates resulted. The use of hypochlorites as bleaching agents discolor denture stain to an even greater extent then the persulfates and perborates. These chlorinated agents have a more serious disadvantage in that they produce an intolerable and unpleasant after taste and odor and may adversely discolor denture metal under certain conditions.

Additionally, although the prior art powder and tablet systems remove some of the denture stain, they tend to leave an undissolved residue which can only be removed mechanically. Consumers usually revert to a soaking and brushing regimen to obtain a thoroughly clean denture. Other types of undissolved residue include chewing gum residue and denture adhesive residue. These residues are particularly difficult to remove even with a regular brushing regimen since they become imbedded in the dentures or partial dentures. This obviously has adverse effects on the denture wearer. Even those chewing gums having non-stick properties and specially formulated for denture wearers become to some extent imbedded in the denture crevices. Denture wearers generally prefer a strong denture adhesive to insure proper adhesive of the denture in the mouth. These types of adhesives have the disadvantage of being very difficult to remove and clean from the denture. The use of water in combination with denture cleanser pastes tend to spread out rather than remove the chewing gum and adhesive residue and therefore fail to clean them from the denture surface. The inventive compositions solve this problem by loosening the chewing gum and adhesive residue such that it can then be removed with gentle rubbing with the fingers.

More recently a liquid denture cleanser has been disclosed in U.S. Pat. No. 4,511,486. This reference discloses a foam-producing liquid composition comprising from about 1 to about 10% by weight of a pharmaceutically acceptable surfactant, about 35 to about 70% by weight of ethanol or isopropanol or mixtures thereof, about 0.1 to about 10% by weight of a pharmaceutically acceptable humectant, about 25 to about 60% water and about 0.5% of an adjuvant. The composition must not contain more than 50% water when 42% alcohol is present and vice versa. Those surfactants disclosed are sodium lauryl sulfate (SLS), sodium dodecyl benzene sulfontates (SDBS), polysorbate 80, poloxomer 407 and mixtures thereof. Humectants are selected from the group consisting of glycerin, sorbitol, polyethylene glycol (PEG), propylene glycol (PG) and mixtures thereof. The use of the trisodium salt of ethylene diamine tetracetic acid (EDTA) in an amount of about 0.5% is also disclosed as a useful adjuvant.

The compositions of this reference rely on their high alcohol content for cleaning. As described hereinafter, comparative tests between the compositions of this reference and the instant invention clearly demonstrate that the compositions of the instant invention are significantly better at removing plaque, calculus, tartar and stains from denture tiles, as well as actual dentures.

FIGS. I and II are photographs of stained dentures. These pictures clearly demonstrate the superior cleaning efficacy of the inventive liquid spray denture compositions over the prior art tableted compositions as well as the prior art liquid denture cleanser of U.S. Pat. No. 4,511,486 described above.

FIGS. III and IV are photographs of stained dentures. These pictures clearly demonstrate the superior cleaning efficiency of the inventive composition over water as the control cleaning agent.

The inventive liquid compositions are designed to be dispensed from a pump spray bottle. Thus, the viscosity of the compositions should be kept within a range which is atomizable or sprayable. The spray is effectuated without aerosol ingredients or pressurized means. The compositions do not use oxidizing agents or chlorine-containing compounds and consequently do not suffer from the disadvantages associated with these agents, as does the prior art. The liquid cleanser is sprayed onto the denture, allowed to stand for about 20 to about 120 seconds and rinsed in tap water. The length of time the cleanser is permitted to remain on the denture is dictated by the type and intensity of stain. Most food, tobacco and plaque stains, however, are easily removed after about 2 minutes of contact with the liquid cleanser. The inventive compositions are particularly effective at removing the calculus and tartar buildup. The instant invention has been shown to be effective in vivo, i.e., on actual dentures, in removing this build-up. If the composition is used regularly, e.g., on a daily basis, very little buildup of stubborn calculus or tartar results. When buildup has occurred on the denture, longer contact time between the cleanser and the denture is required. In such a case, even soaking for a short time might be recommended. The force of the pump spray supplements the cleansing effect of the cleanser. The pump spray force is designed to maximize the removal of food particles and stain on the denture surface. Thus, a minimum spray force is required such that it provides a mechanical cleansing action without a separate brushing step. The maximum force must be kept within a range which is controllable and convenient for the user. This is dictated primarily by consumer acceptability and marketing considerations.

An alternative embodiment to delivery via a pump spray device, is the use of the composition as a soaking solution. In this embodiment, it is suggested that the solution be diluted with water, since it is in a concentrated form.

More particularly, the instant liquid denture cleansing compositions consist essentially of

(a) a detergent present in amounts of about 3 to about 18% by weight selected from the group consisting of sulfonate fatty alcohols having the formula ROSO.sub.3 M, sulfated fatty alcohols having the formula ROSO.sub.4 M, sulfoacetates having the formula ROCOCH.sub.2 SO.sub.3 M and mixtures thereof, wherein R is C.sub.10-16, M is a water soluble alkali metal or alkaline earth metal; and

(b) a chelating agent present in amounts of about 3 to about 18% by weight selected from the group consisting of amino carboxylates, organo phosphonates and mixtures thereof; and

(c) water present in amounts of about 50 to about 94% by weight.

The detergent is preferably used in the range of about 83 to about 12% and most preferably about 7 to about 10% by weight. As can be appreciated, the precise amounts chosen within these ranges will be dictated by the degree and type of stain present.

Preferred ranges of the chelating agent are from about 3 to about 15% by weight and more preferred about 3% to about 8% by weight.

When used in the preferred embodiment, e.g, the sprayable form, the weight ratio of detergent to chelating agent is about 2:1 to about 1:1. If the liquid concentrate is used alternatively as a soaking solution, the ratio is generally about 1:4 to about 1:2.

The use of sulfated higher fatty alcohols as detergents are well known. Such anionic detergents, however, when mixed with a suitable chelating agent, have surprisingly provided a highly effective denture cleanser which, when applied with the application force of a pump spray, provide a more convenient and efficient denture cleanser than the prior art methods. The user is able to clean his dentures without soaking them, as required in the prior art tablet and powder compositions, and without scrubbing or brushing, as required by the prior art sprayable compositions.

It is critical to the invention that the sulfated fatty alcohol detergent be used in conjunction with the recited chelating agents in aqueous solution. Certain of the useful detergents, e.g., sodium lauryl sulfate, when used by themselves and dispensed from a mechanical spraying device or from an aerosol mixture, produce an intolerable atmospheric condition situation which is harmful to the respiratory tract. Uncontrollable sneezing or coughing and respiratory irritation results. Such a situation would restrict the use to well ventilated, controlled areas. It has been discovered, quite unexpectedly, that the inventive compositions can be atomized or sprayed without these harmful side effects, by forming an aqueous mixture of the detergent with the amino carboxylate or organo phosphonate chelating agent. This combination helps alleviate the adverse respiratory and inhalation problems associated with the detergents and increases the cleaning efficacy of the composition. The weight ratio of detergent to chelator recited above has been carefully selected to achieve superior cleaning and to prevent the dispersion of irritating or harmful fumes.

Examples of useful sulfated fatty alcohol detergents are selected from the anionic water soluble class. The potassium, sodium and ammonium salts of the higher alkyl benzene sulfonates are preferred. Among these, the sodium linear alkyl benezene sulfonates are preferred. Other examples include magnesium lauryl sulfate, potassium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium lauryl sulfoacetate, sodium myristyl sulfate, sodium lauryl sulfate, sodium cetyl sulfate, sodium tridecyl sulfate and sodium-7-ethyl-2-methyl-4-undecyl sulfate. Mixtures of any and all of these detergents are also useful.

Other anionic detergents may be incorporated into the composition along with the above required detergents. These supplemental detergents may be present in amounts of about 1 to about 5%. These additional detergents include compounds such as the oleic acid ester of sodium isethionate, sodium N-cyclohexyl-N-palmitoyl taurate, sodium N-coconut acid-N-methyl taurate, sodium N-methyl-N-oleyl taurate and mixtures thereof. Fluorochemical surfactants, commonly known as fluorads, are also useful additives. Examples include those compounds disclosed in British Patent No. 1,322,548, having the formula: ##STR1## wherein n is an integer from 3 to 10, X is bromine or iodine; and Y is a glycol residue having 3 to 10 carbons derived, for example, from ethylene glycol or propylene glycol as an ethyoxylated alcohol having 1 to 10 moles of ethylene or propylene oxide.

The use of chelating or sequestering agents in the prior art was typically in combination with denture cleanser tablets containing peroxygen bleaching agents. The tetrasodium salt of ethylenediamine tetracetic acid (Na.sub.4 EDTA), among others, was commonly used to sequester the heavy metal impurities present in solution and prevent the decomposition of the bleaching agent.

Typically, denture cleansing tablets or powders have used chelating agents such as Na.sub.4 EDTA in amounts of about 0.5%. More recently a denture tablet composition was described in U.S. Pat. No. 4,540,504 to Eoga, whereby from about 10 to about 50% by weight of chelator is present. These prior art references are solid tablet compositions, however, not solutions as in the instant invention. Thus, when the tablets are dissolved in water, and the relative amounts of ingredients are based on the weight of the solution, the chelator range is very small. For example, if the chelator range of tablet of the above-mentioned U.S. Pat. No. 4,540,504 patent is measured based on a weight of the solution it forms when dropped in 125 ml of water, the range is from about 0.16% to about 0.8% by weight. If a typical commercial tablet containing 0.5% Na.sub.4 EDTA is dissolved in 125 ml of water, the chelating concentration based on the then formed solution is 0.012%. These amounts are much smaller than Applicant's range of about 3 to about 18% by weight.

Additional useful amino carboxylate chelators include tetrasodium ethylenediaminetetraacetate dihydrate, trisodium ethylenediaminetetraacetate, diammonium ethylenediaminetetraacetate, disodium ethylenediaminetetracetate dihydrate, trisodium N-hydroxyethylenediaminetriacetate hydrate, trisodium nitrilotriacetate monohydrate, pentasodium diethylenetriaminepentaacetate, trisodium ethylene-diaminetetraacetate trihydrate and mixtures thereof. These chelators, as well as other well known amino carboyxlates are generally used within the above-cited ranges in amounts sufficient to contribute to removal of calculus, tartar and any stain and plaque contained thereon.

Those organic phosphonates useful may be selected from a wide range of conventional materials. Examples include 1-hydroxy-1,1-diphosphonic acid and its sodium, potassium and ammonium salts. These salts are also sold under the tradename Dequest by Monsanto Company. In addition to being chelating agents, the organic phosphonates serve as detergent builders. These chelating agents are employed in the same amounts as the amino carboxylates. Mixtures of any and all of the chelators is also contemplated.

The inventive liquid denture cleansers can optionally contain detergent builders which are conventionally used in detergent formulations and which enhance cleaning and contribute to a brighter surface appearance of the denture. Useful builders include the water-soluble phosphates, pyrophosphates, ortho phosphates, carbonates, and mixtures thereof, and the like. Specific examples of inorganic phosphate builders useful include the sodium or potassium salts of tripolyphosphates, pyrophosphates and hexametaphosphates. These builders may also contribute to cleaning. As mentioned above, the organic phosphonate chelating agents also serve as builders. When incorporated into the composition, builders are generally present in amounts of about 3% to about 12%; and preferably in amounts of about 5% to about 10%.

Other conventional additives such as flavorings, colorants, perfumes, antimicrobials, preservatives (e.g., a paraben or mixtures of parabens), and the like may be optionally incorporated in the inventive compositions. For example, flavorings such as mint, oil of clove, artificial vanilla, to name a few, are useful. These materials may be blended in various combinations and the amounts may be varied according to the perception desired.

In the instance where colorants are used, F.D.& C. and D.& C. dyes may be used. Lakes are generally not useful due to their insolubility in the inventive compositions. Those dyes useful are certified by the Federal Food & Drug Administration as acceptable for use in food, drug and cosmetic applications and in drug and cosmetic colorings. The materials acceptable for the foregoing are preferably water-soluble and include F.D. & C. Blue No. 2 (indigo dye), F.D. & C. Green No. 1 and 3, to name a few. Conventional preservatives such as methyl and propyl paraben and mixtures thereof may be incorporated in amounts well known in the art.

As previously mentioned, the inventive liquid denture, cleanser compositions are designed to be applied to the denture surface from a mechanical spraying device. Simple hand spray pump bottles capable of disposing high viscosity fluids are sufficient. Aerosols, including piston-driven types, are also useful, but are not preferred since they are more costly and do not afford any advantages over the mechanical devices for purposes of this invention. Application by spraying imparts a certain mechanical cleaning force as the liquid hits the denture surface. By directing the spraying parameters, e.g., the spray pattern, the weight of liquid applied and the speed of the spray, the cleaning force can be controlled.

In measuring the force, one fluid once propylene cylindrical pump bottles having a high viscosity spray dispensing head were filled with the inventive compositions. The denture or other target was held stationery in an Instron tensile testing machine. The spray bottle was mounted horizontally above the target with the spray nozzle at a distance of 1" (2.54 cm) away. An air driven piston/solenoid device was used to actuate the spray pump. The air pressure driving the piston was approximately 5 psi (0.35 kg/cm2). The peak force of the spray against the target was recorded by a microprocessor connected to the Instron load cell's output. The measurement was in gram force units. The results indicated that a gram force of at least 1 and preferably between about 1 to 3 is required to provide enough mechanical action to supplement the cleaning effect of the composition itself.

The weight of the liquid dispensed per actuation of the mechanical spraying device was measured by subtracting the weight of the liquid and spray bottle after dispensation with the weight prior to dispensation.

The average weight delivered per actuation is about 90 to about 200 mg of liquid; and preferably about 100 to about 150 mg.+-.25 mg of liquid. These amounts are preferred for adequate cleaning of most stains and plaque.

The spray pattern was determined by stationing the spray pump bottle and directing the spray nozzle onto an absorbant pad situated about 2" (5 cm) away. The pump sprayer was actuated once and the vertical and horizontal diameters of the spray pattern were measured as they appeared on the pad. The spray pattern is preferably about 1.5" (3.81 cm) to about 2.5" (6.35 cm) by 1.5" (3.81 cm) to about 2.5" (6.35 cm) at a distance of about 2" (5 cm) from the target. Most preferably, the spray pattern is about 1.85" (4.6 cm).+-.0.65" (1.65 cm).times.1.85 (4.6 cm).+-.0.65" (1.65 cm) at the 2" (5 cm) distance from the target.

The above measurements were taken to obtain the minimum parameters related to the mechanical force required to achieve cleaning. While the composition itself is a good cleanser, surprisingly improved cleaning of the denture is achieved when the composition is sprayed with sufficient mechanical force to help remove stain, plaque and other debris.

Additional considerations must be given to the choice of detergent/chelator formulation such that the formation of undesirable precipitates is minimized and to prevent the liquid's viscosity from becoming so high that dispensing from a spray bottle is difficult. For example, when ethylenediamine tetracetic tetrasodium salt is used in conjunction with sodium lauryl sulfoacetate (Lanthanol LAL) or another linear alkyl sulfonates, the detergent tends to salt out, forming an insoluble precipitate and resulting in a thick unsprayable mass. Additionally, the cleansing efficacy of the composition is deleteriously affected when such precipitates form. Thus, it is important that the chelators be readily water-soluble and that the combination of the chelator and detergent result in a solution whose viscosity is readily and easily dispensed from a mechanical spraying device, and whose stability is maintained during storage. The viscosity problems and the salting-out effect generally occur at concentrations of chelator above 5% and at temperatures below room temperature. Once the insoluble precipitate is formed it is very difficult to reverse. To help alleviate these problems, agents which depress the freezing point and prevent the formation of insoluble precipitate can be added. Water soluble, non-toxic glycols, such as polyethylene glycols, in an amount sufficient to prevent an insoluble precipitate from forming, are particularly useful in addressing this problem. The addition of these materials in amounts of from about 1 to about 10% by weight help maintain a stable liquid solution during storage or shelf-life. Examples of preferred polyethylene glycols are those having an average molecular weight range of about 200 to about 600. These materials are sold under the trade name Carbowax by Union Carbide, Danbury, Conn. Other non-toxic, water-soluble derivatives of the polyethylene glycols, e.g., alkoxy or ether derivatives are also contemplated.

The term "denture" as used herein, includes artificial teeth, removable orthodontic bridges, dentures, plates and the like.

A high degree of cleansing is generally achieved in less than 1 minute and preferably in 30 seconds or less. The cleansers, with the aid of the mechanical force exerted by the spray, strip off calculus, tartar and plaque, remove mucous resulting from the depositions of proteins and glycoproteins, remove food particles and debris, remove and/or kill bacteria, remove residual denture adhesives and chewing gum, and remove food stains and tobacco stains as well as coffee and tea stains. These compositions have been shown to effectively loosen chewing gum and denture adhesive such that these residues can be easily removed by gently rubbing with the fingers or gentle brushing. These cleansing effects are achieved without adversely affecting the metal, plastic or other materials of the denture construction.

In another embodiment of this invention, the liquid denture cleanser compositions of this invention are formed into a gel using a suitable gel forming material. The gel form can be used in combination with brushing to clean dentures. Thus, the individual who prefers brushing to clean their dentures is provided with a particularly effective cleansing composition in a form convenient for brushing. This embodiment provides a gel denture cleanser composition consisting essentially of.:

(a) a water-soluble detergent present in amounts of about 3 to about 18% by weight selected from the group consisting of sulfonate fatty alcohols having the formula ROSO.sub.3 M, sulfated fatty alcohols having the formula ROSO.sub.4 M, sulfoacetates having the formula ROCOCH.sub.2 SO.sub.3 M and mixtures thereof, wherein R is C.sub.10-16, and M is a water soluble alkali metal or alkaline earth metal--i.e., M is an alkali metal or an alkaline earth metal such that the resulting detergent is water soluble;

(b) a water-soluble chelating agent present in amounts of about 3 to about 18% by weight selected from the group consisting of amino carboxylates, organo phosphonates and mixtures thereof;

(c) an effective amount of a gelling agent; and

(d) water present in amounts such that the total percent of (a)-(d) equals 100%, usually such amounts are within about 50% to about 94% by weight of the total composition.

Yet another embodiment of this invention provides a gel denture cleanser composition consisting essentially of:

(a) a water-soluble detergent present in amounts of about 3 to about 18% by weight selected from the group consisting of sulfonate fatty alcohols having the formula ROSO.sub.3 M, sulfated fatty alcohols having the formula ROSO.sub.4 M, sulfoacetates having the formula ROCOCH.sub.2 SO.sub.3 M and mixtures thereof, wherein R is C.sub.10-16, and M is a water soluble alkali metal or alkaline earth metal--i.e., M is an alkali metal or an alkaline earth metal such that the resulting detergent is water soluble;

(b) a water-soluble chelating agent present in amounts of about 3 to about 18% by weight selected from the group consisting of amino carboxylates, organo phosphonates and mixtures thereof;

(c) an effective amount of a gelling agent;

(d) a water-soluble, non-toxic glycol in an amount sufficient to prevent an insoluble precipitate from forming; and

(e) water present in amounts such that the total percent of (a)-(e) equals 100%, usually such amounts are within about 50% to about 94% by weight of the total composition.

The disclosure above pertaining to the liquid denture cleansing compositions applies equally well to the gel denture cleanser compositions unless indicated otherwise.

The storage stable gel denture cleansing compositions are formed by blending a suitable gel forming agent in effective amounts with the detergent, chelating agent, water and optional glycol components. A suitable gelling agent is a carboxymethylcellulose (CMC) with the sodium salt being preferred--i.e., sodium carboxymethylcellulose. Gelling agents which may prove useful include any suitable gum or thickening agent of either natural, cellulosic, or synthetic origin; cargeenates; alginates; cellulose ethers and esters; and the like. Additional gelling agents which may prove useful include xanthan gum; guar gum; locust gum; Pluronic Polyols; irish moss; gum tragacanth; methyl cellulose; polyvinylpyrrolidone; hydrophilic colloidal carboxyvinyl polymers; and the like. Other gelling agents which may prove useful are described in Peppas, Nikolaos A. (Editor), Hydrogels In Medicine and Pharmacy, Volumes I-III; and in McCutcheon's Functional Materials. published by Allured Publishing Co., Wheaton, Ill., copyright 1983, pages 224-240; the disclosures of each being incorporated herein by reference thereto. The gelling agent (or thickener) is, as stated above, used in amounts which are sufficient for producing a gel with the components utilized in the inventive compositions. The gelling agent may be used in amounts within the range of about 1% to about 50% by weight of the total composition. Generally, from about 0.5% to about 10% by weight of the total composition is suitable with about 1% to about 6% by weight being preferred and about 2% to about 4% by weight being most preferred. The components of the composition are blended together at a suitable temperature, usually room temperature, until the gel is formed and the components are well blended therein. If desired or convenient, heating may be used to dissolve the components and blend them into a gel with the proviso that the temperatures utilized do not adversely effect the components of the composition. Such techniques are well within the capabilities of those skilled in the art.

The chelating agent in the gel composition, as stated above, is used in amounts of about 3% to about 18% by weight of the total composition. Preferably the chelating agent is used in amounts of about 3% to about 15% by weight with about 3% to about 12% being more preferable and about 4.5% to about 10.5% being even more preferable. The weight ratio of detergent to chelating agent is usually about 2:1 to about 1:6 with about 2:1 to about 1:1 being preferred.

The instant invention allows the denture wearer to clean his dentures quickly, conveniently in a portable package without the need for a container for soaking.

A fuller understanding of the present invention will be gained from the following illustrative examples. Unless specified otherwise all amounts expressed as percent are intended to be a percent by weight of the total composition.

Denture Cleanser compositions were prepared using the formulations tabulated below. Compositions A and B represent preferred embodiments of the inventive liquid denture spray composition. Compositions C and D represent commercially available denture tablets.

In vitro denture tiles were prepared with plaque, a composite of food stain consisting of grapes, blueberry, tea and coffee as well as tobacco stain.

Samples of the tiles were then chosen to be cleansed with one of the three compositions listed above. The treatment with Compositions A & B (inventive) were accomplished by spraying the tiles and allowing the spray to remain on each tile type for 30, 60 and 120 seconds prior to rinsing with water at 45.degree. C. for 20 seconds.

The treatment with the tablets of Composition C and D (prior art) was accomplished by dropping the tablets in beakers of 45.degree. C. water containing the tiles. Those tiles treated with Composition C were allowed to soak for 5 minutes. Those tiles treated with Composition D were allowed to soak for 12 minutes.

The results showed that tiles cleaned by the inventive Compositions A and B for 120 seconds were significantly cleaner than those cleaned with Composition C and D.

Those denture tiles which were cleaned with the inventive Compositions A and B for 30 and 60 seconds required an additional spraying and an immediate rinsing in order to achieve similar results to the 120 second treatment.

Those tiles which had 24 hours plaque accumulated on them were sprayed with Compositions A and B and allowed to stand for 12 minutes. Additional plaque tiles were soaked in Compositions C and D for 5 and 12 minutes respectfully. All the tiles were then rinsed under running water at 45.degree. C. for 20 seconds and immersed in a basic 0.01% Fuchsin solution. The Fuchsin solution is used as a color indicator for plaque and calculus. The tiles were the rinsed again and qualitatively compared for red color. The tiles cleaned with Compositions A & B (inventive) had the least amount of red color resulting from the Fuchsin, and consequently the least amount of plaque.

This example is intended to show a comparison between the cleansing efficacy of inventive compositions as compared to a well known commercial tablet of the prior art and the liquid foaming denture cleanser disclosed in U.S. Pat. No. 4,511,486, Composition C.

A set of tiles (Set I) were prepared with coffee, tea, blueberry and grape stains. Another set (Set II) of tiles were prepared having tobacco, coffee, tea, blueberry and grape on a plaque matrix.

FIG. I shows the results of the food stained tiles after cleaning with each of the denture cleansers. "Prior Art I," as labeled in the Figures, is the commercial tableted denture cleanser (Composition D, Example One), which was dissolved in a beaker of water (45.degree. C.) containing the tile and left for 12 minutes.

The "Inventive Composition," as labeled in the FIGURES, is formulation A set forth in Example 1. The spray was left on the tile for 120 seconds and rinsed with water for 20 seconds at 45.degree. C..

"Prior Art II," as labeled in the Figures, is the liquid foaming Composition C set forth in U.S. Pat. No. 4,511,486. The chelator EDTA has been added for the sake of comparison to the instant inventive compositions. This composition had the following formula:

From observing the photographs in FIGS. I and II, the cleaner (whiter) surfaces are those cleansed with the inventive compositions. Those tiles cleaned with the composition of U.S. Pat. No. 4,511,486 did not become clean and therefore exhibit a dark color. These pictures were taken under identical conditions, and accurately reflect the actual appearance after cleaning. It is apparent that the inventive liquid spray denture cleanser compositions exhibited significantly better cleaning than the prior art tableted denture cleanser and the prior art liquid denture cleansers.

Further tests were conducted for the purpose of comparing inventive liquid denture spray composition with those compositions disclosed in U.S. Pat. No. 4,511,486, particularly with respect to their abilities to clean visible tartar and calculus deposits without brushing. Additionally, a preliminary experiment was conducted for the purpose of comparing the respective abilities of the compositions to dissolve hydroxyapatite, the main ingredient found in tartar and calculus deposits. Hydroxyapatite is a major type of calcium phosphate responsible for calculus and tartar deposits. (Schroeder, H. E., Formation & Inhibition of Dental Calculus. Hans Huber Publishers, p 117-119, 1969).

Five denture cleaning solutions were prepared in accordance with the following compositions:

Composition A represents an embodiment of the present invention. Compositions B-E represent compositions of U.S. Pat. No. 4,511.486. The control formulation (F) was ordinary tap water.

Prior to testing the cleaning efficacy of the compositions on tartar and calculus, a preliminary test was conducted to determine the effectiveness of the compositions in dissolving hydroxyapatite (HA), a compound known to be a common type of calculus. To each of the above solution compositions was added powdered hydroxyapatite (HA), the known main ingredient found in tartar and calculus deposits. To 50 ml of the Inventive Composition (A) was added 100 mg of HA. To 100 ml of each of Compositions B-F was added 100 mg of HA. The concentration of HA in the Inventive Compositions (A) was twice that of the prior art (B-F) to emphasize the greater ability of the Inventive Compositions at dissolving HA (calculus).

At the end of two hours of soaking the Inventive Compositions (A) had completely dissolved the HA and the solution remained clear even after one (1) week at room temperature. The prior art and control solutions, however, exhibited cloudy solutions after one (1) week of soaking, indicating failure of these compositions to dissolve the HA. Composition B, which had the least amount of alcohol present relative to compositions C-E, exhibited less cloudiness than the others.

At this point actual dentures were obtained, having visible buildup of tartar and calculus stain and deposits, from subjects. The dentures had not been exposed to any pretreatment whatsoever, nor were the subjects on any special oral hygiene program. The tartar and calculus stains and deposits represented buildup occurring during ordinary usage and hygiene. Photographs of the dentures clearly indicated the buildup.

A denture was selected which was evenly stained with tartar and calculus deposits on both the right and left sides. The denture was first photographed, then rinsed under running water and subjected to the following regimen.

The left side of the denture was soaked in U.S. Pat. No. 4,511,486 Composition B for four (4) hours at room temperature. The denture was the rinsed, air dried and photographed. No visible stain difference was detectable between the side which was treated and untreated side, indicating that no significant removal of the tartar and calculus deposits occurred.

The right side of the same denture was then soaked in the Inventive Composition (A) for one (1) hour at room temperature. The denture was then rinsed, air dried and photographed. The result was that no visible detectable tartar or calculus deposit remained, indicating that the deposits were removed from the denture.

The above experiments indicate the following:

(1) The inventive composition are able to dissolve hydroxyapatite, the main constituent in calculus and tartar, while the prior art compositions of U.S. Pat. No. 4,511,486 are not.

(2) The inventive compositions are capable of removing stubborn calculus and tartar deposits and stain on dentures in one (1) hour of soaking, without brushing or other mechanical action. The compositions of U.S. Pat. No. 4,511,486 did not visibly show any removal of the deposits even after four (4) hours of soaking.

It is therefore evident, in view of this experiment that the inventive denture spray compositions exhibit surprisingly superior results over U.S. Pat. No. 4,511,486.

The following compositions were prepared as a means of demonstrating some of the various combinations possible within the ranges claimed. Those solutions which remained clear during storage are considered preferred embodiments since they remained free of precipitate and were therefore easier to dispense through a spray nozzle. Additionally, those solutions which remained free of precipitate maintained the availability of the total detergent for cleaning. The balancing of amounts of the ingredients within the preferred ranges such that adequate cleaning and sprayability exist, without excessive precipitate, is within the scope of routine experimentation.

Gel denture cleanser compositions of this invention were prepared using the formulations tabulated below:

The gel denture cleanser compositions were prepared by blending the sodium carboxymethylcellulose (NaCMC), either the sodium lauryl sulfate (SLS) or sodium dodecylbenzene sulfonate (SDBS), the ethylenediaminetetraacetic acid tetrasodium salt (Na.sub.4 EDTA), the polyethylene glycol (PEG) and the water together at room temperature (about 21.degree. C.). Blending (mixing) was continued until the gel was formed and all the ingredients were dissolved therein (about 1 hour).

Denture tiles were prepared with coffee, tea, blueberry and grape stain on a plaque matrix. Inventive compositions 1-6 of Example 5 were tested for their ability to clean duplicate sets of denture tiles. Each composition was tested by treating each denture tile of a duplicate set with about 0.5 grams to about 0.6 grams of the composition. The composition was placed on a toothbrush and the denture tile was brushed for about 30 seconds and then rinsed with water at about 45.degree. C. for about 20 seconds. The denture tiles were rinsed using a constant stream of water at a distance of about 3 to about 4 inches from the outlet. Control denture tiles were made in duplicate by placing about 0.5 grams of water on a toothbrush, brushing the denture tile for about 30 seconds, and then rinsing the denture tile with water at about 45.degree. C. for about 20 seconds. There was no change in the stain remaining if the denture tiles were brushed for longer than about 30 seconds. The was no change in the stain remaining when the denture tiles were rinsed for longer than about 20 seconds.

The results obtained are shown in FIGS. III and IV which are photographs of the treated denture tiles. The same control (c) was used in FIG. III and FIG. IV. FIG. III is a photograph of the control denture tiles (C) and the denture tiles (1, 2 and 3) treated with inventive compositions 1, 2 and 3. FIG. IV is a photograph of the control denture tiles and the denture tiles (4, 5 and 6) treated with inventive compositions 4, 5 and 6. Both figures clearly demonstrate that there is significantly less stain (less brown areas) remaining on the denture tiles cleaned with the inventive compositions than on the tiles cleaned with only water (the control).

An attempt was made to prepare comparative gel denture compositions containing alcohol. In one attempt about 3.0 grams of sodium carboxymethylcellulose was mixed with about 70.0 ml of water to produce a gel. Then about 27 ml of 95% ethanol was added and an attempt was made to mix the gel and the ethanol together. It was found that the gel and the alcohol were not miscible and therefore could not be blended together. Adding additional ethanol did not result in miscibility of the gel and the ethanol, the components still could not be blended together into a homogeneous gel.

In another attempt to prepare a gel containing alcohol, about 3.0 grams of sodium carboxymethylcellulose were mixed with about 70.0 ml of water to produce a gel. About 15.0 ml of 95% ethanol were mixed with about 15.0 ml of water. This ethanol and water mixture was added to the ge1 and the resulting blend was mixed. The ethanol and water mixture was miscible with the gel, however, the gel was destroyed as a result of mixing these components together. The resulting mixture was a viscous solution rather than a gelatinous gel.

This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present disclosure is therefore to be considered as illustrative and not restrictive, the scope of the invention being indicated by the appended claims. All modifications which come within the meaning and range of equivalency are intended to be embraced herein.