Improved anticariogenic oral preparations having a pH of about 2.5 to about 5.0 comprise an anticariogenically effective amount of a water-soluble aluminum salt in a surfactant-containing emulsion system suitable for use in the mouth.

BACKGROUND AND SUMMARY OF THE INVENTION 
This invention relates to an oral preparation for use in the prevention of 
dental caries. More particularly, this invention relates to a stable, 
low-pH emulsion for oral administration as a dental caries prophylactic. 
It has been found that aluminum salts can be used in a flavored emulsion 
with selected nonionic surfactants to produce a cariostatically active 
low-PH composition that is both stable and palatable to humans. The oral 
composition may be used in the preparation of a wide variety of products, 
including mouthwashes, chewing gums, prophylaxis pastes, dentifrices, 
dental rinses, and lozenges. 
Anticariogenic preparations are well known in the art. Topical formulations 
containing fluoride, stannous fluoride, or sodium fluoride, for example, 
are known to provide partial protection against dental caries. Although 
effective dental caries protection has been obtained through the use of 
such fluoride-containing compounds, occasional side effects have been 
experienced with certain of the known fluoride-containing anticariogenic 
agents, particularly certain tin-containing salts. A brownish pigmentation 
has been noted after anticariogenic agents containing the stannous ion 
have been applied to the teeth. Although the pigmentation is not 
necessarily undesirable from a physiological standpoint, for aesthetic 
reasons, it would be desirable to provide an effective anticariogenic 
agent that does not discolor enamel. 
The utility of fluoride materials has also been limited by the extent of 
their solubility and stability in aqueous media. For example, sodium 
fluoride is only soluble to the extent of about 4% in water. Furthermore, 
because of toxicity concerns, current regulations imposed by the U.S. Food 
and Drug Administration limit the amount of fluoride that can be provided 
in products sold for over-the-counter use. 
For the foregoing and other reasons, dental researchers have continued 
their efforts to develop new anticariogenic agents which not only 
demonstrate a high level of anticariogenic effectiveness but are 
non-toxic, stable, and widely available. It has been suggested that 
aluminum salts may have a beneficial effect in reducing dental caries or 
in facilitating the uptake of fluoride by the dental enamel. See, e.g., 
Manly, et al., J. Dent. Res. 28: 160 (1948); Regolati, et al., Helv Odont. 
Acta. 13: 59 (1969); and Kelada, "Electrochemical Characteristics of Free 
and Complexed Fluorides in drinking Water and the Effects of Aluminum and 
Iron on Fluoride Incorporation Into Tooth Enamel," Univ. Michigan Thesis 
(1972). 
In vitro studies have shown that pretreatment of enamel with aluminum 
solutions resulted in increased fluoride uptake when followed by treatment 
with a fluoride solution; however, treatment with combinations of aluminum 
and fluoride did not afford any added benefit over that of fluoride alone. 
McCann, Arch. Oral Biol 14:521 (1969); and Gerhardt, et al., J. Dent Res 
51:870 (1972). The foregoing techniques dealt primarily with the use of 
aluminum in combination with fluorides and did not focus on the effect of 
aluminum in the absence of fluoride. 
Nor has the use of aluminum salts in dentifrices demonstrated a desirable 
result, primarily because there has been but recent recognition that 
conventional dentifrice abrasives are incompatible with sources of 
biologically available aluminum (U.S. Pat. No. 4,108,979). While French 
Patent No. 3610M describes a specific combination of aluminum lactate, 
aluminum fluoride, and calcium pyrophosphate, the abrasive interferes with 
aluminum ion activity by forming insoluble aluminum phosphate. Similarly, 
U.S. Pat. No. 3,095,356 uses aluminum salts such as aluminum fluoride to 
coact with insoluble sodium metaphosphate abrasives to reduce the 
solubility of such abrasives and to increase fluoride uptake, but without 
independent therapeutic advantage being taken of the aluminum. 
Canadian Pat. No. 829,272 describes acidic dentifrices comprising a 
combination of surface active substances and albumen-coagulating 
substances such as certain carboxylic acid salts of aluminum and other 
metals. However, this patent fails to teach that the satisfactory use of 
aluminum ions in dentifrices is dependent upon the use of aluminum 
compatible constituents, that is, constituents which when present in 
solution with aluminum ions, do not complex or react with them to render 
said ions unreactive with the surface of teeth. 
U.S. Pat. No. 4,108,981 describes an alkaline mouthwash composition (pH 
7-9) comprising aluminum salts and carboxylic acid. However, that patent 
teaches that the carboxylic acid is required to stabilize the aluminum in 
the mouthwash preparation. Similarly, U.S. Pat. No. 4,153,732 teaches that 
ascorbic and adipic acids can be used to stabilize an aluminum-containing 
comestible. It further teaches that, in fact, many carboxylic acids 
interfere with aluminum ions. (Column 5; lines 7-9). There is nothing to 
suggest the use of aluminum ions without a stabilizing acid, merely that 
certain carboxylic acids are more compatible with aluminum. 
In sum, the prior art has not heretofore suggested a stable anticariogenic 
preparation of aluminum ions at low pH without the presence of carboxylic 
acids and/or fluoride. One of the main problems associated with the 
formulation of such aluminum ion preparations is that aluminum is 
naturally very astringent, tart-tasting, and produces a profound drying 
sensation in the oral cavity. Another problem is that aluminum is very 
reactive and can easily be inactivated by many conventional cosmetic 
ingredients. 
An object of the present invention therefore is to provide a novel, low-pH 
composition for inhibiting dental caries employing aluminum in a 
compatible emulsion system. 
A further object is to provide cariostatically effective 
aluminum-containing oral preparations which are both stable and palatable. 
A still further object is to provide new anticariogenic emulsions useful 
for preparation of mouthwashes, dentifrices, chewing gums, lozenges, and 
prophylaxis pastes. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention is directed to anticariogenic aluminum-containing 
emulsions having a pH of about 2.5 to about 5.0 and adapted for 
application to teeth. The compositions comprise water-soluble aluminum 
salts in an amount sufficient to provide an anticariogenic concentration 
of aluminum ions in an aqueous emulsion stabilized with selected 
surfactants. Preferably for enhanced palatability the present compositions 
include, in addition, one or more substances selected from flavor oils, 
humectants and sweeteners. 
Cariostatically active emulsions of this invention may be prepared by a 
variety of methods so long as aluminum ions are provided in an aqueous 
medium having a PH in the range of about 2.5 to about 5.0. At pH levels 
less than 2.5, the emulsion is generally too astringent-tasting, causes 
erosion of the teeth, and is generally not palatable. Above pH 5.0, 
substantially all of the aluminum is precipitated as aluminum hydroxide. A 
preferred pH range for the present formulation is about 3.0 to about 4.5, 
and more preferably about 3.5 to about 3.9. 
The invention features water-soluble aluminum salts in an emulsion. The 
particular water-soluble aluminum salt employed is not critical, and 
substantially any nontoxic, water-soluble aluminum ion-containing salt may 
be used. Suitable water-soluble aluminum salts include aluminum potassium 
sulfate, aluminum chloride, aluminum sodium sulfate, aluminum sodium 
phosphate, aluminum sulfate, aluminum nitrate, sodium aluminate, and 
mixtures thereof. Other water-soluble aluminum salts are aluminum acetate, 
aluminum ammonium sulfate, aluminum bromate, aluminum bromide, aluminum 
chlorate, aluminum iodide, aluminum lactate, aluminum phenylsulfonate, and 
potassium aluminate. Aluminum potassium sulfate and aluminum chloride are 
preferred by reason of their wide availability and well-established 
safety. The aluminum salts are present in an amount sufficient to provide 
an emulsion having a concentration of available aluminum ions of about 10 
to about 50,000 ppm, preferably about 250 to about 10,000 ppm and 
particularly for mouthwash formulations, most preferably about 500 ppm. 
"Available aluminum ions" for the purpose of defining this invention are 
aluminum ions capable of reacting or complexing with a substance of the 
teeth, including enamel, cementum and dentin. Aluminum ions which are 
complexed with anionic/chelating substances exhibit little if any 
reactivity with tooth surfaces. 
Representative humectant materials useful in this invention include 
glycerin, mannitol, sorbitol, xylitol and mixtures thereof. Glycerin is 
the preferred humectant on the basis of cost, availability, and ability to 
reduce the astringency of the aluminum. Humectant materials are present in 
the emulsion in an amount ranging from about 1 to about 90 percent by 
weight, preferably about 5 to about 60 percent by weight, and more 
preferably, about 5 to about 20 percent by weight. In mouthwash 
formulations, a humectant is typically used at about 10 percent by weight 
of the formulation. 
The emulsion also includes a sweetening agent. Suitable sweeteners include 
sucrose, fructose, levulose, and dextrose, and mixtures thereof as well as 
noncariogenic artificial sweeteners such as saccharin, cyclamate and 
aspartame. Preferably a noncariogenic sweetener is employed in the oral 
composition of this invention. 
Due to the astringent-tasting uncomplexed aluminum compounds, it is 
typically necessary to utilize a flavoring material to mask effectively 
the astringent taste. Representative flavoring oils include oils of 
wintergreen, peppermint, citrus, cassia, cherry, tutti frutti, raspberry, 
root beer, orange, grape, and other suitable flavor oils. The flavor oils 
are present in concentrations ranging from about 0.1 to about 5.0 percent 
by weight and preferably, about 0.2 to about 2.0 percent by weight. For 
most formulations, no more than about 1.0 weight percent flavor oil is 
required to obtain acceptable palatability. 
The emulsions of this invention are predicated on the discovery that 
certain surfactants, especially nonionic hydrophilic surfactants, enable 
formulation of stable, low-pH, flavor oil-aqueous aluminum salt emulsions. 
The use of such aluminum-compatible surfactants enables the formulation of 
stable, aqueous systems containing high flavor oil levels, thereby 
eliminating the need of ethyl alcohol for flavor oil solubilization. 
Nonionic surfactants, in general, tend to decompose at alkaline PH. They 
are, however, quite stable under acidic conditions, as is the case for the 
aluminum compositions of this invention. 
Certain classes of cationic and anionic surfactants have also been 
demonstrated to exhibit surprising compatibility and efficacy in the 
anticariogenic compositions of this invention. Thus aluminum ions have 
also been found to retain "activity" in the presence of art-recognized 
polyalkoxylated, e.g., polyethoxylated and polypropoxylated surfactants, 
particularly polyalkoxy carboxylates, polyalkoxy sulfates and 
polyalkoxylated amines. Polyalkoxylated anionic and cationic surfactants 
possess a sufficient and apparently dominant nonionic character which 
manifests itself in an unexpected level of compatibility with cationic 
aluminum. Quarternary ammonium surfactants and amphoteric surfactants 
derived from the amino acids glycine, cysteine and phenylalanine have also 
exhibited acceptable compatibility with aluminum ions. 
The surfactants used for an aluminum rinse in accordance with this 
invention are non-toxic and water-soluble, each preferably with a dominant 
hydrophilic moiety. The hydrophilic surfactants are nonionic or have the 
aluminum-compatible functionality of nonionic surfactants. 
One suitable nonionic surfactant is a polyoxyethylene derivative of a 
sorbitan fatty acid ester and preferably, a sorbitan mono fatty ester. 
More preferably, the sorbitan mono fatty ester surfactant is a 
polyoxyethylene derivative of a sorbitan fatty acid ester wherein the 
ester-forming fatty acid is selected from lauric acid, palmitic acid, 
oleic acid, and stearic acid. A nonionic surfactant having the desired 
chemical properties is Tween* 20 from Atlas Chemical Industries, Inc. 
Chemically, it is a polyoxyethylene 20 sorbitan monolaurate. Another 
suitable surfactant manufactured by Atlas is SPAN* 80 sorbitan monooleate. 
Another suitable nonionic surfactant is one selected from a class of block 
copolymers of propylene oxide and ethylene oxide. One such water-soluble, 
nontoxic, nonionic surfactant is Poloxamer 407 (tradename Pluronic* Fl27) 
from BASF Wyandotte Company. Its use is discussed in U.S. Pat. No. 
3,864,472 entitled Clear Lemon-flavored Mouthwash. Chemically the 
Pluronics are block copolymers of propylene oxide and ethylene oxide 
containing various amounts of hydrophobe (polyoxypropylene) and hydrophile 
(polyoxyethylene). The Pluronic* F127 is characterized as a hydrophilic 
surfactant. 
The surfactants and surfactant mixtures employed in this invention have a 
composite hydrophile-lipophile-balance (HLB) of between about 9 and about 
30. Preferably, the sorbitan fatty acid ester is a polyoxyethylene 
derivative of sorbitan monolaurate having an HLB of about 9 to about 18, 
preferably about 17, and the block copolymer of propylene oxide and 
ethylene oxide has an HLB of about 15 to about 30, preferably about 22. 
The block copolymer and the sorbitan fatty acid ester are preferably used 
in combination in a ratio of about 2:1 to about 200:1, and more 
preferably, in a ratio of about 4:1 to about 50:1. The present emulsions 
preferably contain about 0.1 to about 5 percent by weight sorbitan fatty 
acid ester and about 0.1 to about 20 percent by weight block copolymer of 
propylene oxide and ethylene oxide. 
The emulsions of the present invention may also contain water-soluble, 
fluoride-containing, anticariogenic adjuvants. Preferably such an adjuvant 
is present in the form of water-soluble, fluoride-containing compounds 
capable of supplying fluoride ions. The preferred adjuvant is sodium 
fluoride, although other materials such as sodium monofluorophosphate, 
stannous fluorozirconate, indium fluorozirconate, stannous fluoride, and 
complex zirconium-germanium fluorides may be employed. Sodium fluoride is 
preferred by virtue of the absence of objectionable taste, lack of enamel 
pigmentation, the freedom from damage to gingival tissue, and by reason of 
anticariogenic effectiveness obtainable therewith. Other suitable 
adjuvants include water-soluble fluoride salts such as NH.sub.4 F, 
SnF.sub.4, KF, InF.sub.3, PbF.sub.2, FeF.sub.2, and LiF, as well as more 
complex water-soluble, fluoride-containing, adjuvants such as 
fluorosilicates, fluorozirconates, fluorostannites, fluoroborates, 
fluorotitanates, fluorogermanates, and mixed halides. Mixtures of suitable 
adjuvants may also be utilized. Aluminum fluoride may be used to supply 
both aluminum and fluoride to the system. In general, such fluoride 
adjuvants are present in anticariogenically effective and non-toxic 
amounts, typically at a level of about 0.05 up to about 1.0 percent by 
weight of the dentifrice preparation so as to provide up to about 1000 ppm 
fluoride ion. 
The emulsions of this invention have demonstrated significant utility as 
anticariogenic agents for use in oral compositions comprising carriers 
such as water and other non-toxic materials. The compositions of this 
invention may be applied to teeth in aqueous solution of such carriers as 
in a topical treatment solution or in the form of a mouthwash. However, 
the compositions of the present invention are also well-suited for 
formulation of other oral compositions for dental caries prophylaxis, 
e.g., dentifrices and prophylaxis pastes/gels containing one or more 
compatible abrasives, lozenges, and chewing gums. Indeed, substantially 
any carrier capable of supplying active aluminum agent to the surface of 
the teeth may be employed in accordance with this invention. 
In a preferred embodiment of the present invention, the emulsion is formed 
by mixing an aqueous solution of the aluminum salts with a sweetener and a 
blocked copolymer of propylene oxide and ethylene oxide. A second mixture 
of a polyoxyethylene derivative of a sorbitan fatty acid ester, flavor 
oil, and glycerin is prepared. The first and second mixtures are 
thereafter blended to form an emulsion of the present invention. 
Emulsions of this invention are employed at their natural pH values, which 
range from about 2.5 to about 5.0 due to the Lewis acid effect of the 
aluminum. In a preferred embodiment, the pH of the emulsion ranges from 
about 3.5 to about 3.8. In all cases, the ingredients provided in the 
emulsions of this invention are selected so as to be compatible with 
aluminum ions.

Exemplary preparations employing the oral compositions of the present 
invention are given in the following Examples 1-5. 
EXAMPLE 1 
______________________________________ 
MOUTHWASH PREATION 
Ingredients % By Weight 
______________________________________ 
Distilled water 85.070 
Pluronic* F127 (BASF Wyandotte) 
3.000 
AlK(SO.sub.4).sub.2 "12H.sub.2 O 
0.885 
Sodium saccharin 0.100 
Glycerin 10.000 
Tween* 20 (ICI Americas) 
0.600 
Flavor oil 0.300 
5% solution F D & C yellow dye #4 
0.040 
5% solution F D & C blue dye #1 
0.005 
100.000% 
______________________________________ 
EXAMPLE 2 
______________________________________ 
DENTIFRICE PREATION 
Ingredients % By Weight 
______________________________________ 
Abrasive 32.00 
Water 20.31 
Glycerin 17.50 
Sorbitol (70%) 14.00 
NaOH (331/3%) 1.00 
Binder 1.00 
Pluronic F-87 9.00 
AlK(SO.sub.4).sub.2 "12H.sub.2 O 
3.54 
Sodium saccharin 0.25 
Tween 20 0.80 
Cassia flavor 0.40 
Methyl paraben 0.15 
Prophyl paraben 0.05 
100.00 
______________________________________ 
EXAMPLE 3 
______________________________________ 
LOZENGE PREATION 
Ingredients % By Weight 
______________________________________ 
Sorbitol (70%) 97.9 
Pluronic F-127 1.2 
A1Cl.sub.3 "6H.sub.2 O 
0.5 
Tween 80 0.2 
Flavorings, color, etc. 
0.2 
100.0 
______________________________________ 
EXAMPLE 4 
______________________________________ 
CHEWING GUM PREATION 
Ingredients % By Weight 
______________________________________ 
Gum Base 26.0 
Sorbitol powder 47.9 
Sorbitol (70%) 17.3 
Glycerin 4.5 
Pluronic F-127 2.0 
Tween 60 0.1 
AlK(SO.sub.4).sub.2 "12H.sub.2 O 
1.0 
Flavoring 1.2 
100.0 
______________________________________ 
EXAMPLE 5 
______________________________________ 
PROPHYLAXIS PASTE PREATION 
Ingredients % By Weight 
______________________________________ 
Abrasive 48.0 
Water 14.0 
Glycerin 10.0 
Sorbitol (70%) 6.0 
NaOH (331/3%) 2.0 
Binders 1.5 
Pluronic - F88 8.0 
Al(NO.sub.3).sub.3 "9H.sub.2 O 
7.0 
Tween 80 1.0 
Sweeteners, flavor, etc. 
2.5 
100.0% 
______________________________________ 
EXPERIMENTAL EVALUATION 
Rat Dental Caries Study 
The significant anticariogenic benefits of the aluminum-containing emulsion 
of this invention have been demonstrated in a dental caries study 
performed with rats. 
The rat dental caries model used was that recommended by the National 
Institute of Dental Research NIH, (Larson, R. H. et al., J. Dent. Res., 
56:1007-1012, 1977). The study was designed to examine the effect of two 
experimental aluminum-containing dental rinses (Groups 3 and 4) on dental 
caries formation in the albino rat. The aluminum rinses were compared to a 
positive control fluoride rinse (Group 5) and two negative control cells 
consisting of water (Group 1) and a placebo rinse (Group 2). Furthermore, 
since aluminum has been demonstrated to enhance the effect of fluoride, a 
double treatment group (Group 6) was included in which the animals were 
treated first with aluminum followed by fluoride 
Twenty litters of eight weanling Wistar strain rats were randomly 
distributed into eight equal groups of 20 animals according to sex, body 
weight, and litter mates. The rats were weighed initially, at one month, 
provided with NIDR cariogenic diet 2000 and distilled drinking water for 
the ten-week study. 
All weanling rats initially were inoculated with the caries-inducing 
microorganisms, Streptococcus mutans 6715. The molars of the rats were 
swabbed with a 24-hour culture of the S. mutans 6715 and the residual was 
placed in their drinking water at a 1:100 dilution. The inoculations were 
repeated for 3 consecutive days to insure implantation of the 
microorganism. 
The formulae for preparation of the dental rinse solutions used for 
treatment Groups 2-5 in the study are set forth in Table 1. 
TABLE 1 
______________________________________ 
Dental Rinse Formulae for Rat Dental Caries Study 
Percentage by Weight 
Group 
Group 2 Group 3 Group 4 
5 
Ingredients Placebo AlK(SO.sub.4).sub.2 
AlCl.sub.3 
NaF 
______________________________________ 
Distilled water 
85.955 84.177 85.062 85.800 
Pluronic* F127 
3.000 3.000 3.00 3.000 
Aluminum potassium 
-- 1.758 -- -- 
sulfate 
dodecahydrate 
Aluminum chloride 
-- -- 0.893 -- 
hexahydrate 
Sodium fluoride 
-- -- -- 0.155 
Sodium saccharin 
0.100 0.100 0.100 0.100 
Glycerin 10.000 10.000 10.000 10.000 
Tween* 0.600 0.600 0.600 0.600 
Citrus flavor 
0.300 0.300 0.300 0.300 
FD&C yellow dye #4 
0.040 0.040 0.040 0.040 
(5% solution) 
FD&C blue dye #1 
0.005 0.005 0.005 0.005 
(5% solution) 
Sodium hydroxide 
-- q.s. q.s. -- 
(331/3%) 
Final pH 6.5 3.8 3.8 6.5 
______________________________________ 
The dental rinse solutions were prepared in accordance with the following 
procedure. The aluminum salt (or NaF) was first dissolved in 90% of the 
water with stirring. The sodium saccharin was then dissolved in the 
solution, following by the Pluronic* Fl27 surfactant. The solution was 
stirred for about one hour to totally dissolve the Pluronic* Fl27. The 
Tween* 20 and flavor oil were mixed in a separate container and the 
glycerin was subsequently added to and mixed with the flavor-oil Tween* 20 
solution. The oil-surfactant mixture was slowly added to the aqueous 
mixture with stirring to form a clear emulsion. Coloring dyes were then 
added to the dental rinses. The pH of the aluminum rinses was slowly 
adjusted to 3.8 with the sodium hydroxide. The rinses were quantitatively 
transferred to a volumetric container of appropriate size, filled with the 
remaining distilled water, and used throughout the entire study. 
Each hemijaw of each rat was swabbed for 15 seconds with the respective 
dental rinse twice daily, five days per week. The group treatment sequence 
was varied each day in order to minimize any potential error due to time 
of day of treatment. 
After final weighing, the treated rats were sacrificed in pairs by 
chloroform inhalation and decapitated. The mandibles and maxillas were 
then surgically removed and defleshed in preparation for caries scoring. 
All animals were coded to prevent identification of the treatment vs. 
control groups by the examiner. 
Dental caries was determined by scoring the number and severity of carious 
areas in sectioned teeth. The mandibles and maxillas were soaked overnight 
in an aqueous 0.05% ammonium purpurate (Murexide) solution to stain the 
decayed enamel. The buccal, lingual, and morsal surfaces were scored using 
a binocular dissection microscope and the location and size of lesions 
recorded on individual caries scoring charts. The hemijaws were 
subsequently sectioned mesially-distally into halves and graded for sulcal 
and proximal lesions. 
The dental caries results are summarized in Table 2. This table includes 
the average final weight, smooth surface caries, and fissure caries 
scores, the percent reductions, and the statistical results. The smooth 
surface caries data, which are a combination of the buccal, lingual, and 
proximal lesion scores, represent the amount of dental decay observed on 
the outer surfaces of the rat teeth. The results demonstrated that the 
AlCl.sub.3, AlK(SO.sub.4).sub.2, and NaF rinses (Groups 3, 4, and 5, 
respectively) significantly reduced smooth surface dental caries by 43, 
37, and 37%, respectively. 
Numerically, the best reduction in smooth surface caries was observed for 
Group 6, which received the dual phase treatment of AlCl.sub.3 and NaF. 
Although the 51% reduction observed for this double treatment group was 
significantly different from the controls, it was not statistically better 
than the 37% reductions observed for the individual NaF or AlCl.sub.3 
treatments 
TABLE 2 
__________________________________________________________________________ 
SUMMARY OF RAT DENTAL CARIES STUDY 
Final Wt. (gm) 
Smooth Surface Caries 
Fissure Caries 
Group 
Treatment.sup.a 
pH 
n Score.sup.b 
Sig..sup.c 
Score.sup.b 
Red..sup.c 
Sig..sup.c 
Score.sup.b 
Red..sup.c 
Sig..sup.c 
__________________________________________________________________________ 
1 Distilled water 
6.5 
20 
239 none 
11.10 
-- 3,4,5,6 
24.45 
-- 3,4,5,6 
2 Placebo 6.5 
20 
241 none 
11.40 
-- 3,4,5,6 
26.80 
-- 3,4,5,6 
3 AlK(SO.sub.4).sub.2 
3.8 
20 
241 none 
6.45 
43% 1,2 17.35 
35% 1,2,5,6 
4 AlCl.sub.3 
3.8 
20 
246 none 
7.20 
37% 1,2 17.35 
35% 1,2,5,6 
5 NaF 6.5 
20 
237 none 
7.15 
37% 1,2 7.45 
72% 1-4 
6 AlCl.sub.3 & NaF 
-- 
20 
242 none 
5.55 
51% 1,2 6.75 
75% 1-4 
__________________________________________________________________________ 
.sup.a All active agents present at a concentration of 0.037 Molar 
.sup.b Mean value, n = 20 
.sup.c The numbers represent the treatment groups which are significantly 
different according to the NewmanKeuls statistical test. 
(Groups 4 and 5, respectively). However, these data seem to indicate that 
aluminum may enhance the effect of fluoride. 
The fissure caries results also summarized in Table 2 are a combination of 
the sulcal and morsal lesions and represent the amount of dental decay 
observed in the pit and fissure areas of the rat molars. The results 
demonstrated that AlCl.sub.3 and AlK(SO.sub.4).sub.2 (Groups 3 and 4), 
significantly reduced the number of fissure caries by 35% each. NaF (Group 
5) significantly reduced fissure caries by 72%. Group 6, treated first 
with AlCl.sub.3, and then NaF, resulted in the greatest reduction in 
fissure caries of 75%. 
The overall results demonstrated that the ingredients used to formulate the 
dental rinse vehicle did not inactivate the aluminum or fluoride and did 
not possess any anticariogenic properties themselves. The rats in all six 
groups exhibited consistent and equivalent weight gains. This, coupled 
with the fact that no deaths occurred during the ten-week study period, 
provided further evidence regarding the lack of toxicity of aluminum. 
Thus, the dental rinse formulation was safe and effective to use as a 
vehicle for administering the aluminum in the human dental caries clinical 
study. 
Human Dental Caries Clinical Investigation 
A human clinical investigation was undertaken to determine the 
effectiveness of a topically-applied aluminum dental rinse prepared in 
accordance with the subject invention in reducing the incidence of dental 
caries compared with a positive control fluoride dentifrice. 
AlK(SO.sub.4).sub.2 was used in the human dental caries study because of 
its GRAS (generally regarded as safe) status with the U.S. Food and Drug 
Administration. 
A total of 260 elementary school children having a high incidence of caries 
was selected from three schools located in a low-fluroide area (0.4 ppm F 
or less in the water supply). All children who were caries-free or had 
fissure sealants or orthodontic appliances were excluded. This precaution 
minimized the natural interference and variability these factors introduce 
into a dental caries clinical study. The children were examined both 
clinically and radiographically for dental caries and stratified into 
three groups. Group 1 served as the positive control and received a 
fluoridated dentifrice approved by the American Dental Association. Group 
2 was given an experimental dental rinse containing 0.81% aluminum 
potassium sulfate with the pH adjusted to 3.8. In order the examine the 
anticariogenic effect of aluminum, it was essential that the subjects in 
Group 2 were not exposed to any exogenous sources of fluoride during the 
study. This necessitated: (1) conducting the study in an area where there 
was minimal fluoride content in the drinking water and (2) providing the 
children in Group 2 with a non-fluoride dentifrice. Group 3 received the 
same rinse as Group 2, but was supplied with the same fluoride dentifrice 
as Group 1 in order to examine the synergistic effect of aluminum and 
fluoride. For ethical reasons there was no placebo. The experimental 
groups were compared to the fluoride dentifrice positive group. 
The dental rinses were self-administered under direct supervision at school 
after the noon meal, 5 days per week. When school was not in session, the 
rinses were self-applied at home under parental supervision. The procedure 
consisted of rinsing for 30 seconds each day with 10 ml of the dental 
rinse. After one month, the children were examined for gingivitis, mucosal 
irritations, enamel decalcification, etc., but no significant side effects 
were observed. 
After six months, the children were again examined clinically and 
radiographically for dental caries. Because all groups exhibited a 
significant or directionaly positive effect at the six-month examination, 
the study was allowed to continue for a one-year examination period. At 
all times the double-blind status of the test was maintained. Examiner 
efficiency was maintained by scheduling reasonable numbers of examinations 
per session with adequate rest periods. 
The dental rinses were as similar in appearance and taste as possible and 
were formulated in a form most palatable to children. The particular 
flavor of the rinses were changed periodically to provide variety and to 
maintain interest. Each batch was checked for enamel solubility reduction 
(ESR) in the laboratory before distribution in order to ensure cariostatic 
activity of the formulation. 
The ESR tests were performed using the method described by Putt and Kleber 
(J. Dent. Res., 64:437-440, 1985). 
Table 3 presents the ESR data for the six various flavored aluminum rinses 
utilized in the clinical study. Enamel dissolution by acid was reduced by 
approximately 70% after treatment with the aluminum dental rinses. The 
data indicated that all the aluminum-containing formulations were highly 
active and no significant incompatibilities occurred between aluminum and 
the other dental rinse ingredients. Placebo formulations without aluminum 
demonstrated no effect whatsoever in reducing enamel solubility, verifying 
that the aluminum was the active component. 
Participants in Group 1 and 3 received adequate supplies of toothbrushes 
and a standard fluoride dentifrice (Crest*) repackaged in unmarked white 
tubes to use at home according to their normal oral hygiene habits. 
Participants in Group 2 were supplied in like manner with a standard 
non-fluoride dentifrice (Pepsodent*). 
Examinations were performed by two dentists experienced in conducting 
dental caries studies. The techniques employed in the dental caries 
examinations were those recommended by the 1955 A.D.A. Dental Caries 
Symposium, the Ohio State Symposium, the 1961 Zurich Caries Symposium, and 
the 1968 A.D.A. Conference on the Clinical Testing of Cariostatic Agents. 
TABLE 3 
__________________________________________________________________________ 
REDUCTION IN ENAMEL SOLUBILITY BY VARIOUS 
FLAVORED DENTAL RINSES USED IN HUMAN CLINICAL STUDY 
Dental Rinse.sup.a Enamel Solubility 
Active Agent Flavor pH 
n Reduction Score.sup.b 
__________________________________________________________________________ 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.3% citrus-mint 
3.8 
3 74 .+-. 3 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.075% cassia 
3.8 
6 71 .+-. 1 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.3% lemon 
3.8 
4 63 .+-. 2 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.3% grape 
3.8 
6 64 .+-. 3 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.3% pineapple 
3.8 
6 69 .+-. 4 
0.885% AlK(SO.sub.4).sub.2.12H.sub.2 O 
0.3% strawberry 
3.8 
6 72 .+-. 3 
None 0.075% cassia 
6.8 
3 -7 .+-. 5 
None 0.3% lemon 
6.8 
3 -8 .+-. 9 
__________________________________________________________________________ 
.sup.a All rinses prepared according to formula in Example 1, except for 
the pineapple flavor in which 1.2% Tween 20 was used. 
.sup.b Mean .+-. standard error 
During the examination procedures neither the examiners nor the trained 
recorder had knowledge of the previous diagnosis or the group assignments. 
Two film, bite-wing radiographs were obtained immediately following the 
clinical examination. The radiographs were developed on-site and retakes 
obtained as needed. 
The subjects were randomly assigned to the study groups after 
stratification based on dental caries susceptibility, dental age, and past 
dental caries experience. Control and test subjects were examined in 
random order. Only permanent teeth were included in the examination and 
diagnostic findings were recorded by teeth and surfaces. When lesions had 
been restored, they were recorded. Extracted teeth were recorded as were 
erupted noncarious teeth. Visual dental caries examination findings were 
called out in code to a trained recorder who wrote the information on an 
individual patient chart for each clinical examination. 
The clinical dental caries findings were expressed in terms of the average 
increase in the number of decayed, missing, and filled teeth (DMFT) and 
surfaces (DMFS) per person in each group. The various components of each 
index, and the distribution on the various surfaces (occlusal, 
buccal-lingual, and proximal) were also obtained. A separate category was 
tabulated for teeth erupting during the study. 
The six-month results for the aluminum rinse dental caries study are 
presented in Table 4. These results demonstrated clinically that aluminum 
is effective in reducing dental caries in humans. 
TABLE 4 
__________________________________________________________________________ 
DENTAL CARIES INCREMENTS AFTER SIX MONTHS 
Treatment DMFT DMFS 
Group 
Rinse Dentifrice 
N Mean 
SEM.sup.c 
% Red 
Sig Mean 
SEM.sup.c 
% Red 
Sig 
__________________________________________________________________________ 
Examiner A 
1 Placebo 
Fluoride.sup.a 
77 
1.00 
0.162 
-- -- 1.62 
0.268 
-- -- 
2 Aluminum.sup.b 
Placebo 
80 
0.58 
0.168 
42% p = .04 
1.04 
0.265 
36% p = .06 
3 Aluminum.sup.b 
Fluoride.sup.a 
80 
0.59 
0.140 
41% p = .03 
0.89 
0.215 
45% p = .02 
Examiner B 
1 Placebo 
Fluoride.sup.a 
77 
0.75 
0.141 
-- -- 1.22 
0.233 
-- -- 
2 Aluminum.sup.b 
Placebo 
80 
0.57 
0.136 
24% p = .18 
0.92 
0.200 
25% p = 0.16 
3 Aluminum.sup.b 
Fluoride.sup.a 
80 
0.67 
0.154 
10% p = .35 
0.97 
0.220 
21% p = 0.22 
__________________________________________________________________________ 
.sup.a Crest.sup. .RTM. With Fluoristat; contains 1100 ppm F as NaF 
.sup.b Contains 500 ppm Al.sup.+3 as AlK(SO.sub.4).sub.2.12 H.sub.2 O, pH 
3.8 
.sup.c Standard error of the mean 
The data in Table 4 demonstrate the differences (W) in decayed, missing, 
and filled teeth (DMFT) and surfaces (DMFS) observed by both examiners 
after six months. The results for Examiner A demonstrated that: (10 a 
30-second rinse with a 500 ppm aluminum solution five days per week 
reduced the DMFT and DMFS significantly better than daily use of a 
positive control fluoride dentifrice by 42% and 36%, respectively; and (2) 
the use of the aluminum rinse in combination with fluoride dentifrice 
resulted in similar statistically significant reductions in DMFT and DMFS 
of 41% and 45% respectively, compared to the fluoride dentifrice positive 
control group. The results of Examiner B likewise demonstrated that the 
two aluminum rinse groups reduced dental caries better than the fluoride 
positive control group. 
The increments in DMFT and DMFS observed by both examiners after one year 
are presented in Table 5. The results confirmed the 6-month data that 
aluminum is effective in reducing dental caries in humans. For the most 
part, the results paralleled the findings for both examiners at six 
months. The results for Examiner A demonstrated that: (1) the 500 ppm 
aluminum dental rinse reduced WDMFT and WDMFS significantly better than 
daily use of a positive control fluoride dentifrice by 38% and 40% 
respectively; and (2) the use of aluminum rinse in combination with 
fluoride dentifrice resulted in similar statistically significant 
reductions in WDMFT and WDMFS of 32% and 32%, respectively, compared to 
the fluoride dentifrice positive control group. Thus, the significant 
caries reductions for aluminum observed by Examiner A at six months were 
still apparent after one year. 
TABLE 5 
__________________________________________________________________________ 
DENTAL CARIES INCREMENTS AFTER ONE YEAR 
Treatment DMFT DMFS 
Group 
Rinse Dentifrice 
N Mean 
SEM.sup.c 
% Red 
Sig Mean 
SEM.sup.c 
% Red 
Sig 
__________________________________________________________________________ 
Examiner A 
1 Placebo 
Fluoride.sup.a 
78 
1.33 
0.21 
-- -- 2.15 
0.35 
-- -- 
2 Aluminum.sup.b 
Placebo 
79 
0.83 
0.19 
38% p = .04 
1.29 
0.28 
40% p = .04 
3 Aluminum.sup.b 
Fluoride.sup.a 
77 
0.91 
0.16 
32% p = .06 
1.47 
0.28 
32% p = .06 
Examiner B 
1 Placebo 
Fluoride.sup.a 
78 
1.12 
0.17 
-- -- 1.90 
0.26 
-- -- 
2 Aluminum.sup.b 
Placebo 
79 
1.04 
0.17 
7% p = 0.37 
1.59 
0.24 
16% p = 0.19 
3 Aluminum.sup.b 
Fluoride.sup.a 
77 
1.06 
0.19 
5% p = 0.40 
1.66 
0.32 
13% p = 0.28 
__________________________________________________________________________ 
.sup.a Crest.sup. .RTM. With Fluoristat; contains 1100 ppm F as NaF 
.sup.b Contains 500 ppm Al.sup.+3 as AlK(SO.sub.4).sub.2.12H.sub.2 O, pH 
3.8 
.sup.c Standard error of the mean 
The results of Examiner B likewise demonstrated that the two aluminum rinse 
groups reduced dental caries better than the fluoride positive control 
group. However, all the percentage reductions were slightly less than 
Examiner A. This is believed to have resulted from the fact that Examiner 
B was not as critical as Examiner A in scoring incipient dental caries. 
The lack of additional cariostatic benefit for aluminum after one year was 
probably the result of the low decay rate during the second six-month 
period and the reduced usage of the aluminum rinses by the subjects due to 
unsupervised rinsing during the summer vacation period. 
Table 6 lists the number of reversals in dental caries observed in each 
group for both examiners at the six-month and one-year examinations, which 
is indicative of remineralization or "healing" of incipient lesions. In 
all cases the two aluminum rinse groups results in a much greater number 
of reversals and of subjects with reversals than in the fluoride positive 
control. This was a very significant finding because it is known that 
fluoride is effective in remineralizing incipient lesions. Thus, reversals 
would be expected for the fluoride positive control. A greater percentage 
of the reversals was noted in the two aluminum groups for both examiners 
after both six and twelve months. For Examiner A, a greater percentage of 
subjects in the fluoride positive control group exhibited an increase in 
dental caries compared to the two aluminum groups. 
TABLE 6 
__________________________________________________________________________ 
SUMMARY OF CHANGES IN DENTAL CARIES IN THE STUDY POPULATION 
Percent Change in Dental Caries of Study Population 
Six Months One Year 
Examiner A 
Examiner B 
Examiner A 
Examiner B 
Group 
Rinse Dentifrice 
Rev. 
NC. 
Inc. 
Rev. 
NC. 
Inc. 
Rev. 
NC. 
Inc. 
Rev. 
NC. 
Inc. 
__________________________________________________________________________ 
1 Placebo 
Fluoride 
12% 
26% 
62% 
12% 
38% 
51% 
10% 
24% 
65% 
4% 
36% 
60% 
2 Aluminum 
Placebo 
19% 
36% 
45% 
20% 
24% 
56% 
15% 
35% 
49% 
11% 
27% 
62% 
3 Aluminum 
Fluoride 
19% 
34% 
48% 
13% 
40% 
48% 
14% 
30% 
56% 
13% 
32% 
56% 
__________________________________________________________________________ 
Rev. = Reversal in Dental Caries 
NC. = No Change in Dental Caries 
Inc. = Increase in Dental Caries 
TABLE 7 
__________________________________________________________________________ 
NUMBER OF CARIES-FREE SUBJECTS OF EACH EXAMINATION 
Caries-Free Subjects 
Examiner A Examiner B 
Treatment Initial 
6-Month 
1-Year 
Initial 
6-Month 
1-Year 
Group 
Rinse Dentifrice 
N (%) N (%) N (%) N (%) N (%) N (%) 
__________________________________________________________________________ 
1 Placebo 
Fluoride 
10 (12%) 
8 (10%) 
6 (8%) 
15 
(17%) 
8 (10%) 
7 (9%) 
2 Aluminum 
Placebo 
9 (10%) 
7 (9%) 
8 (10%) 
14 
(16%) 
8 (10%) 
8 (10%) 
3 Aluminum 
Fluoride 
7 (8%) 
5 (6%) 
6 (8%) 
11 
(13%) 
8 (10%) 
9 (12%) 
__________________________________________________________________________ 
Table 7 presents the number and percentage of subjects having caries-free 
permanent dentition during the course of the study. The number of subjects 
in the fluoride control group declined by one-half, while essentially no 
change was observed in the number of caries-free subjects in the two 
aluminum groups. 
To investigate the possible cariostatic mechanism of aluminum, the clinical 
data for Examiner A were reanalyzed in three different ways: (1) the 
dental caries data for each group were broken down into subcategories with 
respect to tooth location and tooth surface type; (2) the new permanent 
teeth erupting during the study were examined for caries developing in 
each group; and (3) the reversal data for each group were subcategorized 
with respect to tooth location and surface. 
This analysis indicated that the greatest caries protection afforded by the 
aluminum rinses occurred on the buccal surfaces of the posterior teeth 
(although the overall decay rate for buccal surfaces was not that high 
compared to the occlusal and interproximal surfaces). Because the children 
held the aluminum rinse predominantly between their cheeks and the buccal 
surfaces of the posterior teeth while mouth rinsing, it is consistent that 
the buccal surfaces exhibited the greatest reduction in decay because of 
the longer contact time with the aluminum. 
In general, the aluminum rinse provided its second greatest cariostatic 
effect on the occlusal surfaces compared to the fluoride positive control. 
Ordinarily fluoride provides the least effect on the occlusal surfaces. 
Consequently, administration of aluminum in a chewing gum vehicle may 
enable even more prolonged contact with the occlusal surfaces, thus 
providing a means of protecting an area that is both very susceptible to 
decay and generally unprotected by fluoride. 
The aluminum rinse also provided a good effect interproximaly, but had a 
minimal effect on the lingual surfaces. However, the lingual surfaces 
likewise developed minimal dental caries. 
Analysis of dental decay developing in the new permanent teeth that erupted 
during the course of the study demonstrated that very few of the newly 
erupted teeth in all three groups became carious. After one year only 10% 
of the newly erupted teeth in the fluoride positive control exhibited any 
decay on their surfaces. Even a lesser amount of decay (5% to 1%) was 
observed for the two aluminum groups. The predominant location for new 
carious development was the posterior occlusal surface. It appears that 
the aluminum-fluoride dual treatment may provide its greatest effect on 
newly erupting teeth. 
Further analysis of the number and locations of reversals in DMFS occurring 
after six months and one year demonstrated that the majority of reversals 
occurred in the posterior dentition, predominantly with respect to the 
occlusal and interproximal surfaces. Moreover, the two aluminum rinse 
groups resulted in approximately twice as many reversals as fluoride in 
these two locations, especially in the interproximal locations. It 
therefore appears that aluminum provides greater remineralization of 
incipient lesions in those two surfaces most susceptible to dental decay. 
The one-year dental caries clinical study demonstrated that aluminum in an 
acidic (PH 3.8) mouthwash emulsion, formed without use of stabilizing 
carboxylic acids, is a safe and effective agent in reducing the incidence 
of dental caries in humans. The study has given a strong indication that 
aluminum is actually superior to fluoride in cariostatic potential. 
Moreover, in this clinical study the odds were in favor of the Crest 
dentifrice fluoride positive control. It was probably used more than the 
aluminum rinse (daily versus 4-5 times per week), it contained more 
cariostatic agent (1100 ppm F versus 500 ppm Al.sup.+3), and it has been 
clinically proven to prevent dental decay by 40%, compared to the 
approximately 25% reductions noted for most other commercial fluoride 
dentifrices. 
Surfactant Compatibility Study 
Representative samples of surfactants from common chemical subclasses 
within each class (anionic, nonionic, cationic, and amphoteric) of 
surfactants were selected and examined for their effect on enamel 
solubility reduction (ESR) using the procedure described by Applicants in 
J. Dent. Res., 64:437-440 (1985). Results from these studies are presented 
in Tables 8 and 9. 
3 TABLE 8 
ESR, pH, AND VISUAL APPEARANCE OF ANIONIC, NONIONIC, CATIONIC, AND 
AMPHOTERIC SURFACTANTS SURFACTANT CALCIUM ESR PHOSPHORUS ESR 1% CONC. 1 
PTD 4 PTD 1 PTD 4 PTD TYPE OF SURFACTANT EXAMPLE TESTED TRADE NAME 
SOURCE pH SOL. MN SD MN SD MN SD MN SD 
CONTROL distilled water none stock 6.6 tr 2 7 -6 6 14 17 -2 18 I. 
ANIONIC A. Carboxylates 1. regular sodium stearate none stock 10.7 cl, 
fm 10 7 -17 8 13 9 -19 9 2. polyalkoxycarboxylates Sandopan MS-40 
Sandoz 6.1 tr 8 8 -4 1 2 2 -4 1 B. N-Acylsarcosinates Na lauryl sarcosine 
Hamposyl L WR Grace 3.3 i,ppt.26 8 8 8 20 10 5 4 Na lauryl sarcosinate 
Hamposyl L.30 WR Grace 6.6 tr 12 10 -25 14 4 10 -27 7 C. Acylated 
Protein none none none 
Hydrolysates D. Sulfonates 1. alkylbenzenesulfonates Conco AAS-45S Con 
Chem 2. alkylarenesulfonates 3. lignosulfonates 4. naphthalenesulfonates 
Daxad 11 WR Grace 6.6 tr -4 2 2 10 -7 2 -1 8 5. a-olefinsulfonates 
Conco AOS-40 Con Chem 6. petroleum sulfonates 7. dialkylsultosuccinates 
Aerosol OT Am Cyn 5.7 tr -4 7 -3 14 -6 10 -7 13 8. amidosulfonates 
Concogel Con Chem 9. acyl isethionates Dowfax 2A1 Dow Chem 7.5 tr 1 2 
-8 3 -2 3 -11 1 E. Sulfates and Sulfonated Products 1. alcohol sulfates 
Na lauryl sulfate stock 8.0 tr, fm -3 14 -18 10 -3 10 -21 12 2. 
ethoxylated alcohol Conco Sulfate-219 Con Chem sulfates 3. ethoxylated 
alkylphenol Triton X-301 Rohm/Haas 6.7 tr -1 6 -10 9 1 4 -13 7 
sulfates 4. sulfated acids, amides, & esters 5. sulfated oils & fats F. 
Phosphate Esters Na nonoxynol-6 Emphos CS-1361 Witco phosphate II. 
NONIONIC A. Ethoxylates 1. alcohol ethoxylates Brig 35 ICI Amer 3.6 tr 
17 1 -6 13 21 1 -5 13 alkylated polyether Triton X-100 Rohm/Haas 4.1 
tr, fm 8 7 -5 12 7 6 -5 14 alcohol 2. alkylphenol ethoxylates Igepal 
CO-660 GAF Co 6.6 tr 26 1 -3 6 24 1 -7 10 B. Carboxylic (Fatty) Acid 
Esters 1. glycerol esters glycerol monostearate Adacel 165 ICI Amer 
glycerol & polyoxy- Arlacel 165 ICI Amer 4.7 v cl -5 7 -15 9 -7 7 -18 7 
ethylene stearate 2. polyoxyethylene esters Myrj 525 ICI Amer 6.1 tr -1 
6 -2 4 -2 6 -7 5 polyoxyethylene 20 Arlasolve 200 ICI Amer 4.1 tr 2 8 
-6 8 1 8 -7 7 isohexadecyl ether 3. anhydrosorbitol esters Span 20 ICI 
Amer 5.7 cl -3 5 -14 9 -3 4 -13 6 Span 40 ICI Amer Span 60 ICI Amer 
7.3 cl 0 3 0 2 2 6 -3 2 4. ethoxylated Tween 20 ICI Amer 4.8 tr 17 2 -8 
9 17 4 --13 9 anhydrosorbitol esters Tween 60 ICI Amer 4.4 s. cl 15 6 
-4 1 15 7 -6 2 Tween 80 ICI Amer 5. ethoxylated fats, oils, ethoxylated 
castor Emulphor EL719 GAF Co 6.6 tr 1 12 -16 10 4 8 -11 6 & waxes oil 
polyoxyethylene Atlox 1045A ICI Amer 7.0 v. cl -1 7 -2 6 6 17 1 7 
sorbitol oleate- laurate polyoxyethylene G-1441 ICI Amer 7.6 s. cl 8 7 
-12 9 4 12 -11 10 sorbitol lanolin 6. glycerol esters of diethylene 
glycol stock 6.1 i 7 2 -8 8 8 3 -8 10 fatty acids distearate C. 
Carboxylic Amides 1. diethanolamine Condensate PO Con Chem condensates 
2. monoalkanolamine 
condensates 3. polyoxyethylene fatty PEG-6-lauramide Amidox L-5 Stepan 
9.5 tr 0 4 -3 8 -1 5 -2 7 acid amides D. Polyalkene Oxide Block 
Copolymers 1. poly(oxyethylene- Pluronic F127 ICI Amer 5.6 tr, fm -3 11 
-7 0 -6 13 -13 3 co-oxypropylene) Pluronic F87 ICI Amer 6.1 tr, fm 21 
1 -3 4 21 3 -7 2 III. CATIONIC A. Amines 1. oxygen-free amines 2. amine 
oxides lauramine oxide Armonyx LO Stepan 7.5 tr, fm 26 3 -8 9 24 2 -8 7 
3. alkylamine ethoxylates Triton RW-75 Rohm/Haas 10.8 tr -6 8 -11 6 -7 
5 -16 2 4. ethylenediamine Tetronic BASF Wyn 9.0 tr -11 10 -2 3 -16 5 
-9 5 alkoxylates Polyol-704 5. amines with amide 
linkages B. Quarternary coco dimethlammonium Andogen 464 Aldrich 3.9 
cl, fm 9 7 -11 3 13 5 -9 2 Ammonium Salts salt quarternary ammonium 
G-3634A ICI Amer 5.0 tr 1 9 -8 0 -2 9 -8 7 derivative G-263 ICI Amer 
3.9 tr 0 1 -7 3 -3 1 -11 5 IV. AMPHOTERIC A. Amino Acids glycine 6.2 
tr 3 6 0 14 5 7 -3 17 cysteine 4.4 tr 6 13 6 9 7 12 7 6 arginine 
11.0 tr -6 10 -17 24 8 9 -2 19 aspartic 2.9 tr -16 5 -15 12 -8 5 -13 
15 phenylalanine 5.6 tr 14 12 0 19 13 8 0 18 B. Imidazolinium alkyl 
betaine Emcol CC37-18 Witco 
Abbreviations: tr = transparent or clear, cl = cloudy, i = insoluble, fm 
foamy, ppt = precipitate, v = very, s = slightly 
Table 8 presents the data for the surfactant samples tested without 
aluminum present. The table lists the chemical class name of the 
surfactant, the example tested, its corresponding trade name and 
manufacturer, if appropriate, the pH and visible appearance of a 1% test 
concentration, and the resulting enamel solubility reduction (ESR) scores. 
ESR scores represent the percent degree to which the surfactant treatment 
was able to reduce the dissolution of tooth enamel in acid, both 
immediately after treatment (1 PTD scores) and following four additional 
acid demineralizations (4 PTD scores). The higher the score, the better 
the efficiency of the treatment solution. 
In addition to calculating the ESR scores from the amount of enamel calcium 
found in the demineralization solutions, enamel phosphorous was also 
measured as a check. Although essentially equivalent, both the calcium and 
phosphorous ESR scores are presented. Three replicates were conducted in 
order to establish the mean (MN) and standard deviation (SD) values. 
Comparing the ESR data in Table 8 to the distilled water control, it is 
apparent that none of the surfactants by themselves had any significant 
effect in reducing the acid solubility of enamel. The slight effect noted 
for Hamposyl L, Igepal CO-660, Pluronic F87, and Ammonyx LO was probably 
due to a slight coating of the tooth surface by the surfactant. Indeed the 
4 PTD scores show that this effect was totally transient with no residual 
benefit. Most of the surfactant resulted in transparent (tr) aqueous 
solutions, although some produced cloudy (cl) and even insoluble (i) 
mixtures. 
The corresponding pH, visual compatibility, and ESR data for the same 
surfactants combined with 0.005 M AlK(SO.sub.4).sub.2 "12H.sub.2 O are 
presented in Table 9. A low concentration of 0.005 M aluminum was used so 
that any minor interference caused by the surfactants would be more 
readily detected by the ESR procedure. From the data, it is apparent that, 
compared to the aluminum positive control, the anionic surfactant types 
generally are not compatible with aluminum and significantly diminish its 
ability to reduce the acid dissolution of enamel. This is not totally 
unexpected since the negative charge of such anionic surfactants can 
combine with the positively charged aluminum cations to inactivate them. 
Interestingly, the Sandopan MS-40 anionic surfactant is an exception. 
Sandopan MS-40, a polyethoxycarboxylate, had excellent ESR scores, and 
could be used in the present aluminum-containing anticariogenic systems. 
The anionic Triton X-301, an ethoxylated alkylphenol sulfate, also gave an 
acceptable ESR. 
The uncharged, nonionic surfactants resulted in ESR scores indicative of 
good compatibility with aluminum. All of the positively charged cationic 
amine surfactants, except for Tetronic Polyol 704 were incompatible with 
aluminum. Apparently polyalkoxylation of the ethylenediamine moiety 
results in a predominant aluminum compatible nonionic-like character 
comparable to the character described for the polyalkoxycarboxylates 
(sandopan MS-40) above. 
3 TABLE 9 
ESR, pH, AND VISUAL APPEARANCE OF 0.005M ALUMINUM WITH ANIONIC, 
NONIONIC, CATIONIC, AND AMPHOTERIC SURFACTANTS .005M ALUM + CALCIUM ESR 
PHOSPHORUS ESR 1% SURFACTANT 1 PTD PTD 1 PTD 4 PTD TYPE OF SURFACTANT 
EXAMPLE TESTED TRADE NAME SOURCE pH SOL. MN SD MN SD MN SD MN SD 
CONTROL AlK (SO4)2-12H2O alum Baker 4.0 tr 80 3 59 5 81 3 61 6 I. 
ANIONIC A. Carboxylates 1. regular sodium stearate none stock 9.4 ppt, v 
cl 47 11 23 5 50 11 23 4 2. polyalkoxycarboxylates Sandopan MS-40 
Sandoz 3.9 s cl 69 5 31 14 70 3 34 12 B. N-Acylsarcosinates Na lauryl 
sarcosine Hamposyl L WR Grace 2.5 i, ppt 57 12 28 2 57 11 31 3 Na 
lauryl sarcosinate Hamposyl L-30 WR Grace 3.4 ppt, cl 43 4 20 7 46 4 21 
9 C. Acylated Protein none none none Hydrolysates D. Sulfonates 1. 
alkylbenzenesulfonates Conco AAS-45S Con Chem 2. alkylarenesulfonates 
3. lignosulfonates 4. naphthalenesulfonates Daxad 11 WR Grace 4.2 ppt, 
cl 56 2 37 8 56 1 36 8 5. a-olefinsulfonates Conco AOS-40 Con Chem 6. 
petroleum sulfonates 7. dialkylsulfosuccinates Aerosol OT Am Cyn 4.1 
ppt, cl 27 7 -12 16 27 2 -9 13 8. amidosulfonates Concogel Con Chem 9. 
acyl isethionates Dowfax 2A1 Dow Chem 4.1 ppt, s cl 69 4 31 10 66 11 28 
9 E. Sulfates and Sulfonated Products 1. alcohol sulfates Na lauryl 
sulfate stock 4.2 ppt, fm 56 4 27 10 56 2 29 12 2. ethoxylated alcohol 
Conco Sulfate-219 Con Chem sulfates 3. ethoxylated alkylphenol Triton 
X-301 Rohm/Haas 3.9 ppt, s cl 73 9 42 4 68 10 40 4 sulfates 4. sulfated 
acids, amides, & esters 5. sulfated oils & fats F. Phosphate Esters Na 
nonoxynol-6 Emphos CS-1361 Witco phosphate II. NONIONIC A. Ethoxylates 
1. alcohol ethoxylates Brig 35 ICI Amer 3.8 tr 81 2 61 6 82 2 64 4 
alkylated polyether Triton X-100 Rohm/Haas 3.7 tr, s ppt 76 10 66 15 79 
9 65 14 alcohol 2. alkylphenol ethoxylates Igepal CO-660 GAF Co 4.0 tr 
78 4 65 7 80 4 61 7 B. Carboxylic (Fatty) Acid Esters 1. glycerol 
esters glycerol monostearate Adacel 165 ICI Amer glycerol & polyoxy- 
Arlacel 165 ICI Amer 3.9 v cl 80 8 48 10 79 6 46 7 ethylene stearate 2. 
polyoxyethylene esters Myrj 525 ICI Amer 3.8 tr 74 3 39 8 75 3 39 8 
polyoxyethylene 20 Arlasolve 200 ICI Amer 3.9 tr 80 6 58 5 81 5 57 5 
isohexadecyl ether 3. anhydrosorbitol esters Span 20 ICI Amer 3.9 cl 75 
6 44 6 79 5 47 9 Span 40 ICI Amer Span 60 ICI Amer 4.1 cl 72 9 37 6 
73 7 40 7 4. ethoxylated Tween 20 ICI Amer 3.8 tr 73 2 50 9 77 1 50 10 
anhydrosorbitol esters Tween 60 ICI Amer 3.8 cl 78 3 66 7 81 3 65 8 
Tween 80 ICI Amer 5. ethoxylated fats, oils, ethoxylated castor Emulphor 
EL719 GAF Co 3.9 s cl 73 4 35 2 75 4 35 1 & waxes oil polyoxyethylene 
Atlox 1045A ICI Amer 4.0 v cl 79 2 44 4 82 2 49 2 sorbitol oleate- 
laurate polyoxyethylene G-1441 ICI Amer 4.0 s cl 81 5 47 13 81 6 43 11 
sorbitol lanolin 6. glycerol esters of diethylene glycol stock 3.5 i 74 
7 39 5 75 6 40 7 fatty acids distearate C. Carboxylic Amides 1. 
diethanolamine Condensate PO Con Chem condensates 2. monoalkanolamine 
condensates 3. polyoxyethylene fatty PEG-6-lauramide Amidox L-5 Stepan 
4.2 cl 67 16 38 4 67 15 39 3 acid amides D. Polyalkene Oxide Block 
Copolymers 1. poly(oxyethylene- Pluronic F127 ICI Amer 3.8 tr, fm 77 5 
52 17 76 4 49 11 co-oxypropylene) Pluronic F87 ICI Amer 3.8 tr, fm 81 
2 67 2 79 2 61 5 III. CATIONIC A. Amines 1. oxygen-free amines 2. amine 
oxides lauramine oxide Armonyx LO Stepan 4.3 ppt, cl 36 9 21 8 38 10 24 
6 3. alkylamine ethoxylates Triton RW-75 Rohm/Haas 8.8 s cl 1 9 -20 8 4 
8 -23 11 4. ethylenediamine Tetronic BASF Wyn 4.0 s cl 82 6 53 8 81 4 
47 5 alkoxylates Polyol-704 5. amines with amide 
linkages B. Quarternary coco dimethlammonium Andogen 464 Aldrich 3.5 
cl, fm 80 8 52 17 77 8 51 17 Ammonium Salts salt quarternary ammonium 
G-3634A ICI Amer 4.0 tr 77 3 38 6 75 2 36 5 derivative G-263 ICI Amer 
3.9 tr 81 3 61 2 83 2 61 2 IV. AMPHOTERIC A. Amino Acids glycine 4.0 
cl 50 3 30 7 54 3 34 9 cysteine 2.9 tr 71 2 40 9 74 1 42 10 arginine 
9.8 cl 7 10 -24 22 17 11 -16 24 aspartic 2.9 tr 40 8 18 7 37 9 18 6 
phenylalanine 3.7 s cl 70 9 48 9 68 7 38 8 B. Imidazolinium alkyl 
betaine Emcol CC37-18 Witco 
Abbreviations: tr = transparent or clear, cl = cloudy, i = insoluble, fm 
foamy, ppt = precipitate, v = very, s = slightly 
The incompatibility of amines with aluminum in aqueous solution is due to 
the relatively high pH of the amines and/or formation of an insoluble 
aluminum amide salt. The cationic quaternary ammonium salts are, however, 
functional with aluminum. Regarding the dual charged amphoteric 
surfactants, those derived from amino acids of glycine, cysteine, and 
phenylalanine resulted in acceptable ESR scores. Surfactants derived from 
arginine and aspartic acid provided low ESR scores, presumably because of 
their inherent high and low pH, respectively. 
Based on the results of surfactant/aluminum compatibility tests, compatible 
surfactant blends can also be utilized to obtain the optimum HLB 
(hydrophilic-lipophilic balance) required to meet the needs of any 
particular aluminum emulsion system.