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Sodium Alkyl Sulfate as a Detergent in Tooth Paste*
S O D IU M A L K Y L S U L F A T E A S A D E T E R G E N T IN T O O T H P A ST E * B y P A U L C . K I T C H I N , M .S ., D .D .S ., and W . C . G R A H A M , D .D .S ., F .A .C .D ., Colum bus, O h io
SOAP AND THE HYMOLAL SALTS1
C H 8(CH 2)16C O O H
O A P has long been the standard detergent, or washing aid, of the world. From a chemical standpoint, the soaps in common use are either the sodium or the potassium salts of the fatty acids, which are obtained from natural fats, both animal and vegetable. Most of us whose childhood days embraced some farm experience will readily recall the soap making activities which were a corollary of the job of butchering. Just to make the simple process of cooking up wood ash leachings with animal fat as sume a difficult aspect, we might consider for a moment the chemistry involved in the activity that took place in that big soap kettle suspended from a rail tripod over the outdoor fire. Here it is:
(Stearic acid)
S
(Read
before the
Dental
Section of
the
American Association for the Advancement of Science, St. Louis, Mo., January 2, 1936.) *From the College of Dentistry, Ohio State University. Cooperative project carried out under a grant from the Procter and Gamble Co., Cin cinnati, Ohio, to the Ohio State University; work authorized by the board of trustees of the university and under the supervision of the director of industrial research.
1 . Much of the information, especially ma terial lauryl
concerning sulfate,
the given
chemistry of under
the
sodium heading
“ Soap and the Hyraolal Salts” is taken from material issued by the Chemical Division of the Procter and Gamble Co.
Jour. A .D .A . & D. Cos., Vol. 24, M ay 1937
------> C H 3(CH 2)16 COONa (Sodium stearate) (Soft soap)
+
NaOH (Sodium hydroxide) -f
HOH (Water)
If other metals are substituted for so dium and potassium in soap making, the solubility in water is greatly reduced and the cleaning action is correspondingly lessened. Such a substitution occurs, whether we realize it or not, when these soaps made with sodium and potassium are used in water containing calcium and magnesium salts. The amount of these salts in the water varies greatly in differ ent parts of this country, according to the subsurface conditions and the water sup ply. For example, in Cleveland, Ohio, where water for the city is taken from Lake Erie, there are 115 parts in a million of calcium and magnesium salts. In Toledo, Ohio,, where the water supply comes from the Maumee river, and Lake Erie water often is blown back into the river by the wind, this condition may vary from 100 to 300 parts per million. In Columbus, Ohio, the hardness of the water is about 85, and in the city of Washington, D. C., it may be from 50 to 70. In New England, the amounts of calcium and magnesium salts in the water is very much less and there we have what is termed “ soft” water. Now, with a water hardness of 85, with which we are familiar, the insolubility
736
Kitchin and Graham— Sodium Alkyl Sulfate of the calcium fatty acid salt is readily evident in the precipitation of a white
737
during an emergency operation on your car in limestone country, using the water
T a b l e 1.— N u m e r i c a l T o t a l s o f S t a i n e d A r e a s a n d A d v a n t a g e o f S o a p or
Case Number
1 2 3 4 5
A l k y l S u l f a t e P a s t e in E a c h C a s e
Soap Total
Alkyl Sulfate Total
31 26 44 44 17
46 40 46 13
Soap Advantage
Alkyl Sulfate Advantage
21
10 20
4
2 4
6 7 8 9
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
33 34 46 14 69 24 41 61 56 34 32 51 51 18 52 26 69 62 45 48 49 89 62 63 59 32 57 59 59 73 48 40
68 55
curdlike substance in a ring washbowl and bathtub. T o those of you who have move the grime gathered on
41 51 30 23 48 37 40 60 45 41 30 44 41 36 34 37 50 77 47 58 51
8 17 16 9
21 13
1 1 11 7
2 7
10 18 18
11 19 15
2 10 2
86
3
60 63 46 50 53 47 41 39 44 40 37 61
2 13 4
12 18 34 4
,.
31
6
••
158
256
around the of a nearbystream and ordinary soap, the importance of a quest for a detergent tried to re- whose cleansing ability was not dependyour hands ent on the hardness of the local water
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The Journal of the American Dental Association and T h e Dental Cosmos
supply scarcely needs to be emphasized. The same situation touches every house hold and every manufacturer of cloth in hard water areas. When soap is used to wash colored textiles in hard water, the insoluble calcium curd enters into the weave, thereby dimming the color and making the cloth harsh, unpliable and more water resistant. Hence, great chemical laboratories have been enlisted in the search for a detergent that would function equally well in hard and in soft water. In the last few years, this search has been intensified and has resulted in the discovery of some entirely new deter gents which have been named hymolal salts. Chemically, these are salts of sulfated high molecular weight alcohols. T o date, the sodium salts have been most practical. T o illustrate the mode of making these soap substitutes, the following equations will serve: Step 1.— A fatty acid, for example lauric acid, is treated with hydrogen un der tremendous pressure and in the pres ence of a catalyzer. The lauric acid is thus reduced to lauryl alcohol. C H ,(C H 2) 10 COOH (Lauric acid)
+
2H ,
Step 2.— The alcohol is sulfated by treatment with sulfuric acid.
--------- >
H 2SO., (Sulfuric acid)
+
CH 3 (CH2)10 C H 2 HSO 4 (Lauryl acid sulfate)
+
HOH
Step 3.— The lauryl acid sulfate is treated with sodium hydroxide to form the neutral sodium salt. C H 3(CH 2)10 C H aH S 0 4 (Lauryl acid sulfate)
2 C H 3(CH 2)10 C H 2 N aSO , + Ca(HCOs)2 (Sodium lauryl sulfate)
(Calcium bicarbonate)
> C H 3 (Cl I2) 10 CH 2SO< \ p <------ C H 3 (CH 2)10 CH 2S O , / (Calcium lauryl sulfate)
1 jNaH COs 2!NaHCU8
+
(Sodium bicarbonate)
(N o insoluble curd of calcium salt is found here because the calcium lauryl sulfate is also soluble in water.) 2 C H 3(C H 2) 16 COONa
+
C a (H C 0 3)2
(Sodium stearate)
> C H 3(CH 2)16 COO \ C H 3(CH2)16 COO ^
(Calcium bicarbonate) q
, 2 NaHCO» + NaHCO,
(Calcium stearate)
----------> C H 2(CH 2) 10 C H 2 OH + HOH (Lauryl alcohol)
C H ,(C H 2)10 C H 2 OH (Lauryl alcohol)
This sodium lauryl sulfate is the par ticular soap substitute in which we are at present interested as regards its use in tooth-paste. Since other alcohols besides lauryl may be used, the general type of soap substitute is called sodium alkyl sulfate in our experimental work. N ow it will be of interest for us to compare what happens when this soap substitute is used in the hardest water, say in Toledo or Cleveland, with what happens to sodium soap in the same water:
+
NaOH (Sodium hydroxide)
--------► CH3(CHi.)10 CH2NaS04 + (Sodium lauryl sulfate)
HOH
An insoluble curd of calcium stearate is formed. The detergent action of a cleanser is directly proportional to the lack of in soluble residue occurring in the cleaning operation. It is not surprising that, in the light of the foregoing, the manufacturers of tooth pastes and powders have thought it desirable to use this soap substitute in their products. Let it be said to the credit of the commercial interests con trolling the patent rights to the process of making sodium lauryl sulfate that they refused to allow its use by the denti frice makers until they were satisfied that
K itch in and G raham — S odium A lk yl Sulfate
its incorporation in a dentifrice would not result in injury to the oral tissues and also that such a dentifrice would do at least as good a job of cleaning the teeth as the conventional soap products. The determination of these points was referred to the Research Laboratory of the Dental College, Ohio State Uni versity, working under the authorization of the university board of trustees and the general supervision of the director of industrial research, whose main work is cooperation with Ohio industries. EXPERIMENTAL WORK
In undertaking this project, three ob jectives were set up as follow s:
739
tooth paste plus massage and ( c ) massage without tooth paste. It can be added, in this connection, that the gingivae of the persons (dental students) used under the first objective were checked macroscopically throughout the period of test for any evidence of ir ritation due to the tooth pastes used. 3. A determination of the comparative abrasive actions of the two experimental tooth pastes used. As a matter of fact, this determination was made before the first and second test series in order to be sure that the pastes were suitable for further work. This comparison of abrasive action was made necessary be cause of the use of different abrasive maT a b l e 2 .— A b r a s io n T e s t s o f A l k y l S u l f a t e and
Test Number
Abrasion of Soap
Mg. 12.7 12.4
6
9 .8 10.3 9.1 10.5 9 .2 9 .0
Average
9 .6
11.9
3 4 5
1. A determination of the relative cleansing abilities of a tooth paste con taining a sodium alkyl sulfate as its detergent agent as compared with one containing sodium (with some calcium) soap as the detergent factor. 2. A determination of the effect on the oral mucosa of experimental animals of the following: (a) sodium lauryl sul fate tooth paste plus massage, (b) soap
Abrasion of Alkyl Sulfate
Mg. 1 2
Fig. 1 (Case 20).— Method of recording on individual casts residue on buccal and labial aspect of teeth at termination of test periods. Left, results with soap; right, results with alkyl sulfate.
S o ap T oo th P astes
1 2.0 10.6 11.6 12.1
terials in the two pastes. Since the reac tion of the sodium lauryl sulfate is neu tral and that of the soap is alkaline, it was considered desirable to use with each an abrasive of as nearly as possible the same pn as the detergent. Therefore, precipitated chalk was used in the soap paste and calcium phosphate with some sulfate was used with the sodium alkyl sulfate. The detailed formulas of the two pastes are appended to this report. METHODS OF PROCEDURE AND RESULTS OBTAINED
In order to arrive at conclusions re
740
The Journal of the American Dental Association and The Dental Cosmos
garding the cleansing abilities of the ma terials in question, forty students from the junior and senior classes of the dental
A L K Y L SU LPH A TE .
SO AP
and the records were kept on the basis of the assigned numbers. Th e student listed as No. 6 was taken ill after starting the
SO AP
ALKYL
SULPHATE.
A L K Y L SULPHATE
ALKrL SULPHATE Fig. 2.— Results of use of alkyl sulfate and soap in (reading top to bottom) Cases 1 to 4. Left, first period; right, second period.
college were selected as cooperators on this project. Each was given a number
work and hence the data on his case do not appear in the record.
Kitchin and Graham— Sodium Alkyl Sulfate These cooperators, being advanced dental students, were familiar with the normal shapes and arrangement of the teeth and were for this reason in a better position to do a good job of cleaning than a group lacking such training. Before starting on each of the two thirty-day test periods, the teeth of each cooperator received a thorough cleaning i
z
0
0
0
0 0
Fig. 3.— Standards used for determining residue shown by use of disclosing solution on teeth at end of test periods.
741
was done by the cooperators working on each other and was checked by supervisors of this procedure in the dental clinic. In this manner, each cooperator started his test period of thirty days on either of the pastes in question with absolutely clean teeth and the accumulation found on them at the end of the test period was from that period only. A t the beginning of each test period, the cooperator re ceived a check sheet and a direction sheet, a medium hard bristle brush chosen as a standard for this work, two tubes of the particular paste which he was to use and a three-minute sand-glass for timing his brushing. In starting the first period, the odd numbered men were placed on the alkyl sulfate paste and the even num bers on the soap paste. In the second test period, this was reversed, to eliminate the possibility of one or the other of the pastes profiting through the element of
Fig. 4.— Comparison between cleansing actions of sodium alkyl sulfate and soap pastes in each case. T he height of the columns shows the stained residue as determined by the stand ards indicated in Figure 3. Black columns, alkyl sulfate; white, soap.
with proper dental instruments, orangewood stick and pumice. The complete ness of the cleaning was checked in each case by the use of Skinner’s disclosing solution. This preliminary cleaning
practice as the cooperators were using a brushing technic as outlined on the direc tion sheet and presumably somewhat dif ferent from that which they were in the habit of using.
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The Journal of the American Dental Association and The Dental Cosmos
Fig. 5.— Section of gingival tissue with histologic evidence of irritation in form of infiltration of plasma and polymorphonuclear and other leukocytic cells.
Each cooperator was required to make two accurate models of his upper and lower teeth in white artificial stone. These two sets of models, consisting of
one upper and one lower each, were used at the ends of the test periods for the purpose of sketching on each tooth (buc cal or labial side only) the shape and ex
Kitchin
and Graham— Sodium Alkyl Sulfate
tent of any residue brought out by the disclosing solution as a dark brown stain resisting a flushing with warm water after the solution had been in place for
743
20. The residue left after the test period on soap paste is shown on the left, while the residue left after the alkyl sul fate period is at the right. All the sketch-
Fig. 6.— Section through gingival tissue of Dog 1 in which surface of tissue had been mas saged over a thirty day period with sodium lauryl sulfate tooth paste.
twenty seconds. Figure 1 is a front, left and right view of such a set of models made from the teeth of cooperator No.
ing on the models was done by one person, Case 20 was one of those that showed a superior result for soap paste.
744
The Journal of the American Dental Association and The Dental C osm os
Fig. 7.— Section through gingival tissue of Dog 1 in which surface had been massaged without toothpaste.
Because of the fact that the stain of the disclosing solution is not a permanent one, but fades after a short time, the following procedure was used in all
cases: The solution was applied first only to those teeth in the upper right half of the arch and the sketching done on the model at once. The upper left
Kitchin and Graham— Sodium Alkyl Sulfate
745
Fig. 8.— Section of gingival tissue from Dog 2 in which massage was done with soap paste.
half was next subjected to the stain and sketches were made. The lower teeth were then handled in the same manner. As mentioned above, the stain was al
lowed to act for twenty seconds before flushing of the tooth surface with warm water to remove the excess solution. After the staining for the purpose of
746
The Journal of the American Dental Association and The Dental Cosmos
Fig. 9.— Section of gingival tissue from Dog 2 in which massage was carried out without tooth paste.
sketching the residual areas on the stone models, stain was again applied to the entire buccal and labial surfaces, allowed to remain for twenty seconds and flushed
with warm water, and photographs were made of the anterior teeth in each case. An Eastman clinical camera and Eastman superspeed portrait film was used. The
Kitchin and Graham— Sodium Alkyl Sulfate
'• í ^ ? W
’ Sí,r »
;t¡pSí.,
747
M-í- ?:íS(íKvíh
ÿ
ía fts is i
jaci?
'ü i Hf
v>-» .. . í::'VÍ|E p ,¡ '' ■& ! » il
¡¡1 6
¡p p p
■ H § Fig. 10.— Section of gingival tissue from Dog 3 on side massaged with sodium alkyl sulfate paste.
shutter opening was 11 and the time of exposure was one-half second. Th e light
was uniform, being from two kodalites of 500 watts each located uniformly in
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The Journal of the American Dental Association and The Dental Cosmos
Fig. 11.— Sec*ion, of gingival tissue from Dog 3 on side massaged with soap tooth paste.
all cases. Figure 2 shows the photographs of the mouths of cooperators 1 to 4, inclu sive, on the two pastes tested. W hile these photographs were made of all the mouths as matters of record, the sketches of the
residual areas on the individual teeth of the stone models served as the principal objects of study in the determination of the cleansing ability of the soap and alkyl sulfate pastes. After all the sketch-
Kitchin and Graham— Sodium Alkyl Sulfate
749
Fig. 12.— Section of gingival tissue from Dog 4 on side which was massaged with fingers only.
ing of areas had been done for both test periods, a series of typical stained areas to be used as standards of comparison was set up to better evaluate the residual
stained areas. These standards are shown in Figure 3. W hile the standards are shown on incisor type teeth, they are easily adapted to apply to the bicuspids
750
The Journal o f the American Dental Association and The Dental Cosmos
and molars. The areas were given a nu merical value as shown above the differ ent types. In all except 5, there is more than one arrangement under each value.
of the buccal or labial surface. This ex treme condition was limited to second and third molar locations. A graphic illustration of the total re-
Fig. 13.— Section of gingival tissue from D og 4- on side on which no massage of any kind was done.
As will be observed, the numerical values are roughly approximate to the area involved, 5 indicating a complete coverage
suits in each individual case is given in Figure 4. In this same graph is also indicated, by means of relative position,
Kitchin and Graham— Sodium Alkyl Sulfate which paste was used first and which was used second by the cooperator. A ques tion related to the condition of the paste after a period of storage, and hence its use in the first or second test period, will be discussed later. In such a method of scoring as has been used in this phase of the work, the shorter column in each case shows the material which has made the better showing with that particular cooperator. T o secure a more concrete idea of the total group differences and to show more distinctly those cases in which the soap or
Fig. 14.— Abrasion machine. Above, com plete apparatus; below, individual test unit. 1 , adjustment screws for level position. 2 , level. 3, brush. 4, brush-holder set screw. 5, power arm set screw. 6, brush-holder set screw. 7, adjustments for side play. S, screw holding power arm. 1 0 - 1 1 , drive wheels. 1 2 , revolution recorder. 13, copper abrasion plate. 14, metal container for holding test material.
alkyl sulfate possessed decided advan tages, Table 1 was compiled. Considering the entire group of cooperators, the cleansing power of the soap paste was about 62 per cent that of the alkyl sulfate, or, conversely, the alkyl
751
sulfate paste was approximately 162 per cent as efficient as was the soap paste. An analysis of Table 1 indicates that, taking into consideration only differences of ten or more, eight cooperators showed a marked cleansing advantage for the soap paste. O f these eight, an inspection of Figure 4 shows that they all used the soap paste in the first test period. During the course of the work, it was noted that, owing to the fact that the tubes of paste were stored upside down, when these particular men were given the alkyl sul fate paste, after an interval of about sixty days, it was rather dry and hard to force from the tube. It is thought possible that the detergent might have been somewhat lacking in the upper part of the tube as it was used by the cooperator. There was no indication of hardening on the part of the soap paste after storage. On the other hand, of the twelve persons in whom a marked cleansing advantage for the alkyl sulfate paste was evident, three used the soap paste first, and this seems to throw some doubt on the theory that storage of the alkyl sulfate paste inter fered with its cleansing power. This point should be further investigated by chemical analysis of different parts of the tube of stored alkyl sulfate paste. W e are frank to admit that we can give no explanation as to why, if the alkyl sulfate is a better detergent when used with “ hard” water, as was done throughout these tests, a much larger proportion of the cooperators did not show a marked superiority for it. Every attempt was made to reduce variables to the single one of the paste used. Those cooperators who showed marked advan tage for the soap paste were questioned as to any dislike of the taste of the alkyl sulfate paste that might have influenced them in any way to slight its use. T w o of the eight admitted that they disliked it, but denied any slighting of it on that
752
The Journal o f the American Dental Association and The Dental Cosmos
basis. The other six of this group fa vored the alkyl sulfate over the soap paste on the basis of taste. Referring to Table 1, we find that twelve of the cooperators showed an ad vantage for the alkyl sulfate paste by dif ferences of ten or more. In a few cases, the differences exceeded thirty. O f this group of twelve, ten used the alkyl sul fate during the first test period and two used it during the second period after a considerable time of storage as noted above. Another point that was brought out in the course of this investigation was that the use of the alkyl sulfate paste caused certain food materials and beverages con sumed shortly after the cleaning of the teeth to taste bad. Six of the cooperators said that orange juice tasted “ spoiled,” and one remarked that coffee tasted bit ter. Since the large majority of these students did not get orange juice and many did not use coffee, this could not be checked over the entire group. One of the writers checked this on himself, and there was no doubt in his case that the bad after-effect on these commonly used breakfast items was a fact. This is a point that should be investigated as to its elimination from alkyl sulfate tooth paste. It is a problem for the chemist. Referring to the superior cleansing power of the soap paste in some of the cases, it might be a possibility that a chemical analysis of the saliva of this group as compared to that of those who had better results with the alkyl sulfate might throw some light on this matter. If we take all the data obtained on the cleansing power of the two pastes into consideration, it is believed that the alkyl sulfate paste has not suffered by compari son with the sodium soap paste and pos sibly it has shown some advantage over it in a majority of the cases wherein a
marked difference was apparent in the group of thirty-nine persons studied. EFFECT OF THE USE OF ALKYL SULFATE PASTE, SOAP PASTE AND MASSAGE ON THE MUCOSA
The effect on the oral mucous mem brane was observed in two ways. In the group of cooperators, it was studied both subjectively and objectively. In no case was any deleterious effect apparent on examination of the mouths of these per sons and in no case did a cooperator re port any irritation that could have been ascribed to the use of either of the pastes. In order that any effects might be noted microscopically, four young dogs were used as experimental animals. They were kept at Ivorydale and treated by H. G. M iller as follows: D og 1 (Female).— The right side of the lower buccal gingiva and the adjacent cheek mucosa were massaged for one min ute, twice daily, for a period of thirty days, with the fingers of the operator covered with alkyl sulfate tooth paste. Immediately after the massage, the paste was flushed from the mouth with warm water. The left side was treated in a similar manner, but without the paste. D og 2 (Female).— The right side was treated as above except that soap paste was used. The left side was massaged with the fingers only. D og 3 (Male).— The right side was massaged with alkyl sulfate paste for one minute and immediately rinsed. The left side was massaged for a similar period with soap paste and immediately rinsed. D og 4 (M ale).— The right side was massaged with the fingers only for one minute. The left side received no treat ment whatever.
It was first planned to brush the teeth and gingivae of the dogs with a brush similar to that furnished the student cooperators, but it happened that the dogs resented this so violently that the
Kitchin and Graham— Sodium Alkyl Sulfati
753
hematoxylin, 1 per cent alcoholic eosin and 0.5 per cent orange G . Sections were mounted in balsam and studied for signs of inflammation. A t the time the dogs were killed, the mucosae were observed for any macroscopic evidence of irrita tion. There was none evident in any case. Fifty serial sections were cut from each tissue block. After staining and
finger massage had to be used. The dogs were all from the same litter and were 2 months old at the time of starting and approximately 3 months old when killed. A t the end of the experimental period, the dogs were anesthetized and killed. The medial parts of the lower jaw and the adjacent cheek tissues were removed and placed at once in 10 per cent forma-
Formulas of the Tooth Pastes Used Soap Tooth Paste Ingredient
Parts by Weight
Tragacanth gel (7J gum tragacanth, 1 benzoic acid, 91J water) Olive oil soap (sodium soap) Calcium salt of olive oil fatty acids (calcium soap) Glycerol C.P. W ater Sugar, granulated Sodium chloride Soluble saccharin Oil o f peppermint, U.S.P. Precipitated calcium carbonate, U .S.P.
10.0 3.0 1.5 12.5 19.6 3.6 0.5 0.05 1.5 59.0
Alkyl Sulfate Tooth Paste Tragacanth gel Mineral oil (nujol) Glycerol, C.P. Water Oil o f peppermint, U.S.P. Sodium alkyl sulfate* Sugar, granulated Sodium chloride Soluble saccharin Pyran (mixture of calcium pyrophosphate and calcium sulfate)
10.0 1.0 12.5 2.5 1.5
2.0
8.6
2.0 0.05 63.0
*A commercial product showing by analysis: 0 .5 %
N a H COs W ater Sodium chloride Alcohol, soluble Alcohol, insoluble Hart SOs Disodic sulfate Sodium alkyl sulfate (mostly lauryl)
1.0 0.4 71.8 26.1 17.8 24.7
68.1
lin. The bone tissue was decalcified in 5 per cent nitric acid, dehydrated and embedded in hot celloidin. Serial sections of bone and adjacent soft tissue were cut and stained with Delafield’s
mounting, these were examined with the microscope for cellular evidence of in flammation. In order to give an example of what such a condition might present, Figure 5 is shown. This illustrates a
754
The Journal of the American Dental Association and The Dental Cosmos
marked degree of cellular infiltration in gingival tissue. Figure 6 is a gingival section taken from dog 1. It shows the condition in the tissue after its being massaged over a thirty-day period with alkyl sulfate paste. There is no evidence of round-cell infil tration indicative of inflammation. There is marked epithelial keratinization. Figure 7 shows a section o f gingival tissue from the side which was massaged with the fingers only. It does not differ in any material way from that shown in Figure 6. Figure 8 is a gingival section from dog 2, in which the massage was done with the soap paste. There is marked epithelial keratinization, but no inflam mation. Figure 9 shows a section of gingival tissue from the other side of the jaw of the same dog, which was massaged with the fingers only. It differs in no material way from the side treated with the soap paste. Figure 10 is a gingival section from the side of dog 3 that was massaged with alkyl sulfate paste. Again, there is marked epithelial keratinization, but no inflammation. Figure 11 is from the other side of the same dog, which was massaged with soap paste. There is no inflammation, but again marked epithelial keratiniza tion. Figure 12 is a section of gingival tis sue from dog 4 from the side which was massaged with the fingers only. There is no inflammation, but a marked keratin ization o f epithelium. Figure 13 is from the opposite side of the same dog, where there was no mas sage used and no paste applied. There is a relatively small amount of epithelial keratinization. From the evidence presented here, we believe that neither the use o f soap paste nor the alkyl sulfate paste has resulted in
any sign o f inflammation in the experi mental animals examined. It has been interesting to note the effect of massage, with or without toothpaste, in the in crease of keratinized epithelium covering the gingiva of the alveolar process. RELATIVE ABRASIVE POWERS OF THE TWO PASTES TESTED
As has been stated before, it was con sidered advisable to use different abrasive agents with the soap and alkyl sulfate pastes in order not to interfere with the natural reactions of these two detergents. Because this variation introduced the possibility of considerable difference in abrasive action of the two pastes, it was necessary to determine just what this dif ference might be in order not to confuse detergent and abrasive activity. T h e ap paratus used to make these abrasion tests was one devised in the research labora tory of one of the prominent tooth-paste manufacturers. It is illustrated in Figure 14. A small electric motor connected by gears to a main crankshaft furnishes the power. Six samples can be handled at one run. Clean polished copper plates, weighed accurately to tenths of a milli gram, are used to ascertain the loss in weight by abrasion of the material being tested. Each copper plate is sealed in its respective container by means of 4 drops of paraffin, confined, of course, to the under side of the plate and the bottom of the container. Medium hard bristle brushes with their bristle ends in a plane surface are adjusted to a plane coincident with the upper surface o f the copper plate on which the individual brush will work. Twenty grams of the paste to be tested is well mixed with 10 gm. of distilled water, placed in the metal con tainer and covering the copper plate. The recorder, or counter, is set at zero and the machine run until the reading is 50,000. This means that the brush
Kelly— Supervised Eruption travels the length of the copper plate 100,000 times. A single test requires a period of about 5 hours. The container is then removed from the apparatus and washed free of all residue with hot water. This also removes the paraffin. The copper plate is then washed in al cohol and ether and weighed to tenths of a milligram. Subtraction of this weight from the initial weight of the same plate gives the loss due to the abrasive action of the paste tested. Six samples each of the soap paste and the sodium alkyl sulfate paste were thus tested. Samples were taken from separate containers after the contents of each had been well mixed. The results of these tests are given in Table 2. T h e soap paste proved to be slightly more abrasive on the basis of these tests, but the difference was so little, 2.3 mg.,
755 we believe it to be a negligible factor in the test conducted with the group of thirty-nine cooperators for the determina tion of cleansing ability. SUMMARY
1. In a total of thirty-nine mouths, alkyl sulfate tooth paste was a superior cleanser to soap paste in twelve individual cases; soap tooth paste was superior to alkyl sulfate paste in eight individual cases. Th e remainder of the group tested showed a marked superiority for neither. 2. There was no evidence of inflamma tory reaction in the soft tissues under the use of either the alkyl sulfate tooth paste or the soap tooth paste. 3. The difference in abrasive action of the alkyl sulfate paste and the soap paste was so slight as to be negligible in any comparison of cleansing ability.
SU PE R V ISE D E R U P T IO N B y W . S. K E L L Y , D .D .S ., Chicago, 111.
F
O R approximately six years, I have had to deal with an increasing num ber of children presenting an inade quate development of the mandible interfering with the eruption of the six permanent anterior teeth. These chil dren come from families with adequate means, and have , almost all been un der the care of pediatricians since birth. Growth appeared to be normal or above in all cases; the average mentality was high, and there appeared to be less than the average incidence of upper respiratory infections. T h e inadequate expansion of the man dible was producing a malposition of the permanent teeth in these children which would eventually require corrective Jour. A .D .A . & D. Cos., Vol. 24, M ay 1937
measures. As it seemed unethical to per mit these to become corrective cases, I designed two castings which embraced the lingual aspect of the deciduous pos terior teeth up to and including the de ciduous cuspid, no bands being necessary. A lingual spring exerted a gentle, ex pansive force, which augmented normal expansion sufficiently to give each pair of permanent teeth sufficient space. It was found that the point of attachment and the force exerted by the spring must be carefully adjusted, and that the appli ance need only be kept in place for ap proximately the time required for the eruption of each pair of permanent an terior teeth. The overlap of the upper arch made
SOAP AND THE HYMOLAL SALTS1
C H 8(CH 2)16C O O H
O A P has long been the standard detergent, or washing aid, of the world. From a chemical standpoint, the soaps in common use are either the sodium or the potassium salts of the fatty acids, which are obtained from natural fats, both animal and vegetable. Most of us whose childhood days embraced some farm experience will readily recall the soap making activities which were a corollary of the job of butchering. Just to make the simple process of cooking up wood ash leachings with animal fat as sume a difficult aspect, we might consider for a moment the chemistry involved in the activity that took place in that big soap kettle suspended from a rail tripod over the outdoor fire. Here it is:
(Stearic acid)
S
(Read
before the
Dental
Section of
the
American Association for the Advancement of Science, St. Louis, Mo., January 2, 1936.) *From the College of Dentistry, Ohio State University. Cooperative project carried out under a grant from the Procter and Gamble Co., Cin cinnati, Ohio, to the Ohio State University; work authorized by the board of trustees of the university and under the supervision of the director of industrial research.
1 . Much of the information, especially ma terial lauryl
concerning sulfate,
the given
chemistry of under
the
sodium heading
“ Soap and the Hyraolal Salts” is taken from material issued by the Chemical Division of the Procter and Gamble Co.
Jour. A .D .A . & D. Cos., Vol. 24, M ay 1937
------> C H 3(CH 2)16 COONa (Sodium stearate) (Soft soap)
+
NaOH (Sodium hydroxide) -f
HOH (Water)
If other metals are substituted for so dium and potassium in soap making, the solubility in water is greatly reduced and the cleaning action is correspondingly lessened. Such a substitution occurs, whether we realize it or not, when these soaps made with sodium and potassium are used in water containing calcium and magnesium salts. The amount of these salts in the water varies greatly in differ ent parts of this country, according to the subsurface conditions and the water sup ply. For example, in Cleveland, Ohio, where water for the city is taken from Lake Erie, there are 115 parts in a million of calcium and magnesium salts. In Toledo, Ohio,, where the water supply comes from the Maumee river, and Lake Erie water often is blown back into the river by the wind, this condition may vary from 100 to 300 parts per million. In Columbus, Ohio, the hardness of the water is about 85, and in the city of Washington, D. C., it may be from 50 to 70. In New England, the amounts of calcium and magnesium salts in the water is very much less and there we have what is termed “ soft” water. Now, with a water hardness of 85, with which we are familiar, the insolubility
736
Kitchin and Graham— Sodium Alkyl Sulfate of the calcium fatty acid salt is readily evident in the precipitation of a white
737
during an emergency operation on your car in limestone country, using the water
T a b l e 1.— N u m e r i c a l T o t a l s o f S t a i n e d A r e a s a n d A d v a n t a g e o f S o a p or
Case Number
1 2 3 4 5
A l k y l S u l f a t e P a s t e in E a c h C a s e
Soap Total
Alkyl Sulfate Total
31 26 44 44 17
46 40 46 13
Soap Advantage
Alkyl Sulfate Advantage
21
10 20
4
2 4
6 7 8 9
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
33 34 46 14 69 24 41 61 56 34 32 51 51 18 52 26 69 62 45 48 49 89 62 63 59 32 57 59 59 73 48 40
68 55
curdlike substance in a ring washbowl and bathtub. T o those of you who have move the grime gathered on
41 51 30 23 48 37 40 60 45 41 30 44 41 36 34 37 50 77 47 58 51
8 17 16 9
21 13
1 1 11 7
2 7
10 18 18
11 19 15
2 10 2
86
3
60 63 46 50 53 47 41 39 44 40 37 61
2 13 4
12 18 34 4
,.
31
6
••
158
256
around the of a nearbystream and ordinary soap, the importance of a quest for a detergent tried to re- whose cleansing ability was not dependyour hands ent on the hardness of the local water
738
The Journal of the American Dental Association and T h e Dental Cosmos
supply scarcely needs to be emphasized. The same situation touches every house hold and every manufacturer of cloth in hard water areas. When soap is used to wash colored textiles in hard water, the insoluble calcium curd enters into the weave, thereby dimming the color and making the cloth harsh, unpliable and more water resistant. Hence, great chemical laboratories have been enlisted in the search for a detergent that would function equally well in hard and in soft water. In the last few years, this search has been intensified and has resulted in the discovery of some entirely new deter gents which have been named hymolal salts. Chemically, these are salts of sulfated high molecular weight alcohols. T o date, the sodium salts have been most practical. T o illustrate the mode of making these soap substitutes, the following equations will serve: Step 1.— A fatty acid, for example lauric acid, is treated with hydrogen un der tremendous pressure and in the pres ence of a catalyzer. The lauric acid is thus reduced to lauryl alcohol. C H ,(C H 2) 10 COOH (Lauric acid)
+
2H ,
Step 2.— The alcohol is sulfated by treatment with sulfuric acid.
--------- >
H 2SO., (Sulfuric acid)
+
CH 3 (CH2)10 C H 2 HSO 4 (Lauryl acid sulfate)
+
HOH
Step 3.— The lauryl acid sulfate is treated with sodium hydroxide to form the neutral sodium salt. C H 3(CH 2)10 C H aH S 0 4 (Lauryl acid sulfate)
2 C H 3(CH 2)10 C H 2 N aSO , + Ca(HCOs)2 (Sodium lauryl sulfate)
(Calcium bicarbonate)
> C H 3 (Cl I2) 10 CH 2SO< \ p <------ C H 3 (CH 2)10 CH 2S O , / (Calcium lauryl sulfate)
1 jNaH COs 2!NaHCU8
+
(Sodium bicarbonate)
(N o insoluble curd of calcium salt is found here because the calcium lauryl sulfate is also soluble in water.) 2 C H 3(C H 2) 16 COONa
+
C a (H C 0 3)2
(Sodium stearate)
> C H 3(CH 2)16 COO \ C H 3(CH2)16 COO ^
(Calcium bicarbonate) q
, 2 NaHCO» + NaHCO,
(Calcium stearate)
----------> C H 2(CH 2) 10 C H 2 OH + HOH (Lauryl alcohol)
C H ,(C H 2)10 C H 2 OH (Lauryl alcohol)
This sodium lauryl sulfate is the par ticular soap substitute in which we are at present interested as regards its use in tooth-paste. Since other alcohols besides lauryl may be used, the general type of soap substitute is called sodium alkyl sulfate in our experimental work. N ow it will be of interest for us to compare what happens when this soap substitute is used in the hardest water, say in Toledo or Cleveland, with what happens to sodium soap in the same water:
+
NaOH (Sodium hydroxide)
--------► CH3(CHi.)10 CH2NaS04 + (Sodium lauryl sulfate)
HOH
An insoluble curd of calcium stearate is formed. The detergent action of a cleanser is directly proportional to the lack of in soluble residue occurring in the cleaning operation. It is not surprising that, in the light of the foregoing, the manufacturers of tooth pastes and powders have thought it desirable to use this soap substitute in their products. Let it be said to the credit of the commercial interests con trolling the patent rights to the process of making sodium lauryl sulfate that they refused to allow its use by the denti frice makers until they were satisfied that
K itch in and G raham — S odium A lk yl Sulfate
its incorporation in a dentifrice would not result in injury to the oral tissues and also that such a dentifrice would do at least as good a job of cleaning the teeth as the conventional soap products. The determination of these points was referred to the Research Laboratory of the Dental College, Ohio State Uni versity, working under the authorization of the university board of trustees and the general supervision of the director of industrial research, whose main work is cooperation with Ohio industries. EXPERIMENTAL WORK
In undertaking this project, three ob jectives were set up as follow s:
739
tooth paste plus massage and ( c ) massage without tooth paste. It can be added, in this connection, that the gingivae of the persons (dental students) used under the first objective were checked macroscopically throughout the period of test for any evidence of ir ritation due to the tooth pastes used. 3. A determination of the comparative abrasive actions of the two experimental tooth pastes used. As a matter of fact, this determination was made before the first and second test series in order to be sure that the pastes were suitable for further work. This comparison of abrasive action was made necessary be cause of the use of different abrasive maT a b l e 2 .— A b r a s io n T e s t s o f A l k y l S u l f a t e and
Test Number
Abrasion of Soap
Mg. 12.7 12.4
6
9 .8 10.3 9.1 10.5 9 .2 9 .0
Average
9 .6
11.9
3 4 5
1. A determination of the relative cleansing abilities of a tooth paste con taining a sodium alkyl sulfate as its detergent agent as compared with one containing sodium (with some calcium) soap as the detergent factor. 2. A determination of the effect on the oral mucosa of experimental animals of the following: (a) sodium lauryl sul fate tooth paste plus massage, (b) soap
Abrasion of Alkyl Sulfate
Mg. 1 2
Fig. 1 (Case 20).— Method of recording on individual casts residue on buccal and labial aspect of teeth at termination of test periods. Left, results with soap; right, results with alkyl sulfate.
S o ap T oo th P astes
1 2.0 10.6 11.6 12.1
terials in the two pastes. Since the reac tion of the sodium lauryl sulfate is neu tral and that of the soap is alkaline, it was considered desirable to use with each an abrasive of as nearly as possible the same pn as the detergent. Therefore, precipitated chalk was used in the soap paste and calcium phosphate with some sulfate was used with the sodium alkyl sulfate. The detailed formulas of the two pastes are appended to this report. METHODS OF PROCEDURE AND RESULTS OBTAINED
In order to arrive at conclusions re
740
The Journal of the American Dental Association and The Dental Cosmos
garding the cleansing abilities of the ma terials in question, forty students from the junior and senior classes of the dental
A L K Y L SU LPH A TE .
SO AP
and the records were kept on the basis of the assigned numbers. Th e student listed as No. 6 was taken ill after starting the
SO AP
ALKYL
SULPHATE.
A L K Y L SULPHATE
ALKrL SULPHATE Fig. 2.— Results of use of alkyl sulfate and soap in (reading top to bottom) Cases 1 to 4. Left, first period; right, second period.
college were selected as cooperators on this project. Each was given a number
work and hence the data on his case do not appear in the record.
Kitchin and Graham— Sodium Alkyl Sulfate These cooperators, being advanced dental students, were familiar with the normal shapes and arrangement of the teeth and were for this reason in a better position to do a good job of cleaning than a group lacking such training. Before starting on each of the two thirty-day test periods, the teeth of each cooperator received a thorough cleaning i
z
0
0
0
0 0
Fig. 3.— Standards used for determining residue shown by use of disclosing solution on teeth at end of test periods.
741
was done by the cooperators working on each other and was checked by supervisors of this procedure in the dental clinic. In this manner, each cooperator started his test period of thirty days on either of the pastes in question with absolutely clean teeth and the accumulation found on them at the end of the test period was from that period only. A t the beginning of each test period, the cooperator re ceived a check sheet and a direction sheet, a medium hard bristle brush chosen as a standard for this work, two tubes of the particular paste which he was to use and a three-minute sand-glass for timing his brushing. In starting the first period, the odd numbered men were placed on the alkyl sulfate paste and the even num bers on the soap paste. In the second test period, this was reversed, to eliminate the possibility of one or the other of the pastes profiting through the element of
Fig. 4.— Comparison between cleansing actions of sodium alkyl sulfate and soap pastes in each case. T he height of the columns shows the stained residue as determined by the stand ards indicated in Figure 3. Black columns, alkyl sulfate; white, soap.
with proper dental instruments, orangewood stick and pumice. The complete ness of the cleaning was checked in each case by the use of Skinner’s disclosing solution. This preliminary cleaning
practice as the cooperators were using a brushing technic as outlined on the direc tion sheet and presumably somewhat dif ferent from that which they were in the habit of using.
742
The Journal of the American Dental Association and The Dental Cosmos
Fig. 5.— Section of gingival tissue with histologic evidence of irritation in form of infiltration of plasma and polymorphonuclear and other leukocytic cells.
Each cooperator was required to make two accurate models of his upper and lower teeth in white artificial stone. These two sets of models, consisting of
one upper and one lower each, were used at the ends of the test periods for the purpose of sketching on each tooth (buc cal or labial side only) the shape and ex
Kitchin
and Graham— Sodium Alkyl Sulfate
tent of any residue brought out by the disclosing solution as a dark brown stain resisting a flushing with warm water after the solution had been in place for
743
20. The residue left after the test period on soap paste is shown on the left, while the residue left after the alkyl sul fate period is at the right. All the sketch-
Fig. 6.— Section through gingival tissue of Dog 1 in which surface of tissue had been mas saged over a thirty day period with sodium lauryl sulfate tooth paste.
twenty seconds. Figure 1 is a front, left and right view of such a set of models made from the teeth of cooperator No.
ing on the models was done by one person, Case 20 was one of those that showed a superior result for soap paste.
744
The Journal of the American Dental Association and The Dental C osm os
Fig. 7.— Section through gingival tissue of Dog 1 in which surface had been massaged without toothpaste.
Because of the fact that the stain of the disclosing solution is not a permanent one, but fades after a short time, the following procedure was used in all
cases: The solution was applied first only to those teeth in the upper right half of the arch and the sketching done on the model at once. The upper left
Kitchin and Graham— Sodium Alkyl Sulfate
745
Fig. 8.— Section of gingival tissue from Dog 2 in which massage was done with soap paste.
half was next subjected to the stain and sketches were made. The lower teeth were then handled in the same manner. As mentioned above, the stain was al
lowed to act for twenty seconds before flushing of the tooth surface with warm water to remove the excess solution. After the staining for the purpose of
746
The Journal of the American Dental Association and The Dental Cosmos
Fig. 9.— Section of gingival tissue from Dog 2 in which massage was carried out without tooth paste.
sketching the residual areas on the stone models, stain was again applied to the entire buccal and labial surfaces, allowed to remain for twenty seconds and flushed
with warm water, and photographs were made of the anterior teeth in each case. An Eastman clinical camera and Eastman superspeed portrait film was used. The
Kitchin and Graham— Sodium Alkyl Sulfate
'• í ^ ? W
’ Sí,r »
;t¡pSí.,
747
M-í- ?:íS(íKvíh
ÿ
ía fts is i
jaci?
'ü i Hf
v>-» .. . í::'VÍ|E p ,¡ '' ■& ! » il
¡¡1 6
¡p p p
■ H § Fig. 10.— Section of gingival tissue from Dog 3 on side massaged with sodium alkyl sulfate paste.
shutter opening was 11 and the time of exposure was one-half second. Th e light
was uniform, being from two kodalites of 500 watts each located uniformly in
748
The Journal of the American Dental Association and The Dental Cosmos
Fig. 11.— Sec*ion, of gingival tissue from Dog 3 on side massaged with soap tooth paste.
all cases. Figure 2 shows the photographs of the mouths of cooperators 1 to 4, inclu sive, on the two pastes tested. W hile these photographs were made of all the mouths as matters of record, the sketches of the
residual areas on the individual teeth of the stone models served as the principal objects of study in the determination of the cleansing ability of the soap and alkyl sulfate pastes. After all the sketch-
Kitchin and Graham— Sodium Alkyl Sulfate
749
Fig. 12.— Section of gingival tissue from Dog 4 on side which was massaged with fingers only.
ing of areas had been done for both test periods, a series of typical stained areas to be used as standards of comparison was set up to better evaluate the residual
stained areas. These standards are shown in Figure 3. W hile the standards are shown on incisor type teeth, they are easily adapted to apply to the bicuspids
750
The Journal o f the American Dental Association and The Dental Cosmos
and molars. The areas were given a nu merical value as shown above the differ ent types. In all except 5, there is more than one arrangement under each value.
of the buccal or labial surface. This ex treme condition was limited to second and third molar locations. A graphic illustration of the total re-
Fig. 13.— Section of gingival tissue from D og 4- on side on which no massage of any kind was done.
As will be observed, the numerical values are roughly approximate to the area involved, 5 indicating a complete coverage
suits in each individual case is given in Figure 4. In this same graph is also indicated, by means of relative position,
Kitchin and Graham— Sodium Alkyl Sulfate which paste was used first and which was used second by the cooperator. A ques tion related to the condition of the paste after a period of storage, and hence its use in the first or second test period, will be discussed later. In such a method of scoring as has been used in this phase of the work, the shorter column in each case shows the material which has made the better showing with that particular cooperator. T o secure a more concrete idea of the total group differences and to show more distinctly those cases in which the soap or
Fig. 14.— Abrasion machine. Above, com plete apparatus; below, individual test unit. 1 , adjustment screws for level position. 2 , level. 3, brush. 4, brush-holder set screw. 5, power arm set screw. 6, brush-holder set screw. 7, adjustments for side play. S, screw holding power arm. 1 0 - 1 1 , drive wheels. 1 2 , revolution recorder. 13, copper abrasion plate. 14, metal container for holding test material.
alkyl sulfate possessed decided advan tages, Table 1 was compiled. Considering the entire group of cooperators, the cleansing power of the soap paste was about 62 per cent that of the alkyl sulfate, or, conversely, the alkyl
751
sulfate paste was approximately 162 per cent as efficient as was the soap paste. An analysis of Table 1 indicates that, taking into consideration only differences of ten or more, eight cooperators showed a marked cleansing advantage for the soap paste. O f these eight, an inspection of Figure 4 shows that they all used the soap paste in the first test period. During the course of the work, it was noted that, owing to the fact that the tubes of paste were stored upside down, when these particular men were given the alkyl sul fate paste, after an interval of about sixty days, it was rather dry and hard to force from the tube. It is thought possible that the detergent might have been somewhat lacking in the upper part of the tube as it was used by the cooperator. There was no indication of hardening on the part of the soap paste after storage. On the other hand, of the twelve persons in whom a marked cleansing advantage for the alkyl sulfate paste was evident, three used the soap paste first, and this seems to throw some doubt on the theory that storage of the alkyl sulfate paste inter fered with its cleansing power. This point should be further investigated by chemical analysis of different parts of the tube of stored alkyl sulfate paste. W e are frank to admit that we can give no explanation as to why, if the alkyl sulfate is a better detergent when used with “ hard” water, as was done throughout these tests, a much larger proportion of the cooperators did not show a marked superiority for it. Every attempt was made to reduce variables to the single one of the paste used. Those cooperators who showed marked advan tage for the soap paste were questioned as to any dislike of the taste of the alkyl sulfate paste that might have influenced them in any way to slight its use. T w o of the eight admitted that they disliked it, but denied any slighting of it on that
752
The Journal o f the American Dental Association and The Dental Cosmos
basis. The other six of this group fa vored the alkyl sulfate over the soap paste on the basis of taste. Referring to Table 1, we find that twelve of the cooperators showed an ad vantage for the alkyl sulfate paste by dif ferences of ten or more. In a few cases, the differences exceeded thirty. O f this group of twelve, ten used the alkyl sul fate during the first test period and two used it during the second period after a considerable time of storage as noted above. Another point that was brought out in the course of this investigation was that the use of the alkyl sulfate paste caused certain food materials and beverages con sumed shortly after the cleaning of the teeth to taste bad. Six of the cooperators said that orange juice tasted “ spoiled,” and one remarked that coffee tasted bit ter. Since the large majority of these students did not get orange juice and many did not use coffee, this could not be checked over the entire group. One of the writers checked this on himself, and there was no doubt in his case that the bad after-effect on these commonly used breakfast items was a fact. This is a point that should be investigated as to its elimination from alkyl sulfate tooth paste. It is a problem for the chemist. Referring to the superior cleansing power of the soap paste in some of the cases, it might be a possibility that a chemical analysis of the saliva of this group as compared to that of those who had better results with the alkyl sulfate might throw some light on this matter. If we take all the data obtained on the cleansing power of the two pastes into consideration, it is believed that the alkyl sulfate paste has not suffered by compari son with the sodium soap paste and pos sibly it has shown some advantage over it in a majority of the cases wherein a
marked difference was apparent in the group of thirty-nine persons studied. EFFECT OF THE USE OF ALKYL SULFATE PASTE, SOAP PASTE AND MASSAGE ON THE MUCOSA
The effect on the oral mucous mem brane was observed in two ways. In the group of cooperators, it was studied both subjectively and objectively. In no case was any deleterious effect apparent on examination of the mouths of these per sons and in no case did a cooperator re port any irritation that could have been ascribed to the use of either of the pastes. In order that any effects might be noted microscopically, four young dogs were used as experimental animals. They were kept at Ivorydale and treated by H. G. M iller as follows: D og 1 (Female).— The right side of the lower buccal gingiva and the adjacent cheek mucosa were massaged for one min ute, twice daily, for a period of thirty days, with the fingers of the operator covered with alkyl sulfate tooth paste. Immediately after the massage, the paste was flushed from the mouth with warm water. The left side was treated in a similar manner, but without the paste. D og 2 (Female).— The right side was treated as above except that soap paste was used. The left side was massaged with the fingers only. D og 3 (Male).— The right side was massaged with alkyl sulfate paste for one minute and immediately rinsed. The left side was massaged for a similar period with soap paste and immediately rinsed. D og 4 (M ale).— The right side was massaged with the fingers only for one minute. The left side received no treat ment whatever.
It was first planned to brush the teeth and gingivae of the dogs with a brush similar to that furnished the student cooperators, but it happened that the dogs resented this so violently that the
Kitchin and Graham— Sodium Alkyl Sulfati
753
hematoxylin, 1 per cent alcoholic eosin and 0.5 per cent orange G . Sections were mounted in balsam and studied for signs of inflammation. A t the time the dogs were killed, the mucosae were observed for any macroscopic evidence of irrita tion. There was none evident in any case. Fifty serial sections were cut from each tissue block. After staining and
finger massage had to be used. The dogs were all from the same litter and were 2 months old at the time of starting and approximately 3 months old when killed. A t the end of the experimental period, the dogs were anesthetized and killed. The medial parts of the lower jaw and the adjacent cheek tissues were removed and placed at once in 10 per cent forma-
Formulas of the Tooth Pastes Used Soap Tooth Paste Ingredient
Parts by Weight
Tragacanth gel (7J gum tragacanth, 1 benzoic acid, 91J water) Olive oil soap (sodium soap) Calcium salt of olive oil fatty acids (calcium soap) Glycerol C.P. W ater Sugar, granulated Sodium chloride Soluble saccharin Oil o f peppermint, U.S.P. Precipitated calcium carbonate, U .S.P.
10.0 3.0 1.5 12.5 19.6 3.6 0.5 0.05 1.5 59.0
Alkyl Sulfate Tooth Paste Tragacanth gel Mineral oil (nujol) Glycerol, C.P. Water Oil o f peppermint, U.S.P. Sodium alkyl sulfate* Sugar, granulated Sodium chloride Soluble saccharin Pyran (mixture of calcium pyrophosphate and calcium sulfate)
10.0 1.0 12.5 2.5 1.5
2.0
8.6
2.0 0.05 63.0
*A commercial product showing by analysis: 0 .5 %
N a H COs W ater Sodium chloride Alcohol, soluble Alcohol, insoluble Hart SOs Disodic sulfate Sodium alkyl sulfate (mostly lauryl)
1.0 0.4 71.8 26.1 17.8 24.7
68.1
lin. The bone tissue was decalcified in 5 per cent nitric acid, dehydrated and embedded in hot celloidin. Serial sections of bone and adjacent soft tissue were cut and stained with Delafield’s
mounting, these were examined with the microscope for cellular evidence of in flammation. In order to give an example of what such a condition might present, Figure 5 is shown. This illustrates a
754
The Journal of the American Dental Association and The Dental Cosmos
marked degree of cellular infiltration in gingival tissue. Figure 6 is a gingival section taken from dog 1. It shows the condition in the tissue after its being massaged over a thirty-day period with alkyl sulfate paste. There is no evidence of round-cell infil tration indicative of inflammation. There is marked epithelial keratinization. Figure 7 shows a section o f gingival tissue from the side which was massaged with the fingers only. It does not differ in any material way from that shown in Figure 6. Figure 8 is a gingival section from dog 2, in which the massage was done with the soap paste. There is marked epithelial keratinization, but no inflam mation. Figure 9 shows a section of gingival tissue from the other side of the jaw of the same dog, which was massaged with the fingers only. It differs in no material way from the side treated with the soap paste. Figure 10 is a gingival section from the side of dog 3 that was massaged with alkyl sulfate paste. Again, there is marked epithelial keratinization, but no inflammation. Figure 11 is from the other side of the same dog, which was massaged with soap paste. There is no inflammation, but again marked epithelial keratiniza tion. Figure 12 is a section of gingival tis sue from dog 4 from the side which was massaged with the fingers only. There is no inflammation, but a marked keratin ization o f epithelium. Figure 13 is from the opposite side of the same dog, where there was no mas sage used and no paste applied. There is a relatively small amount of epithelial keratinization. From the evidence presented here, we believe that neither the use o f soap paste nor the alkyl sulfate paste has resulted in
any sign o f inflammation in the experi mental animals examined. It has been interesting to note the effect of massage, with or without toothpaste, in the in crease of keratinized epithelium covering the gingiva of the alveolar process. RELATIVE ABRASIVE POWERS OF THE TWO PASTES TESTED
As has been stated before, it was con sidered advisable to use different abrasive agents with the soap and alkyl sulfate pastes in order not to interfere with the natural reactions of these two detergents. Because this variation introduced the possibility of considerable difference in abrasive action of the two pastes, it was necessary to determine just what this dif ference might be in order not to confuse detergent and abrasive activity. T h e ap paratus used to make these abrasion tests was one devised in the research labora tory of one of the prominent tooth-paste manufacturers. It is illustrated in Figure 14. A small electric motor connected by gears to a main crankshaft furnishes the power. Six samples can be handled at one run. Clean polished copper plates, weighed accurately to tenths of a milli gram, are used to ascertain the loss in weight by abrasion of the material being tested. Each copper plate is sealed in its respective container by means of 4 drops of paraffin, confined, of course, to the under side of the plate and the bottom of the container. Medium hard bristle brushes with their bristle ends in a plane surface are adjusted to a plane coincident with the upper surface o f the copper plate on which the individual brush will work. Twenty grams of the paste to be tested is well mixed with 10 gm. of distilled water, placed in the metal con tainer and covering the copper plate. The recorder, or counter, is set at zero and the machine run until the reading is 50,000. This means that the brush
Kelly— Supervised Eruption travels the length of the copper plate 100,000 times. A single test requires a period of about 5 hours. The container is then removed from the apparatus and washed free of all residue with hot water. This also removes the paraffin. The copper plate is then washed in al cohol and ether and weighed to tenths of a milligram. Subtraction of this weight from the initial weight of the same plate gives the loss due to the abrasive action of the paste tested. Six samples each of the soap paste and the sodium alkyl sulfate paste were thus tested. Samples were taken from separate containers after the contents of each had been well mixed. The results of these tests are given in Table 2. T h e soap paste proved to be slightly more abrasive on the basis of these tests, but the difference was so little, 2.3 mg.,
755 we believe it to be a negligible factor in the test conducted with the group of thirty-nine cooperators for the determina tion of cleansing ability. SUMMARY
1. In a total of thirty-nine mouths, alkyl sulfate tooth paste was a superior cleanser to soap paste in twelve individual cases; soap tooth paste was superior to alkyl sulfate paste in eight individual cases. Th e remainder of the group tested showed a marked superiority for neither. 2. There was no evidence of inflamma tory reaction in the soft tissues under the use of either the alkyl sulfate tooth paste or the soap tooth paste. 3. The difference in abrasive action of the alkyl sulfate paste and the soap paste was so slight as to be negligible in any comparison of cleansing ability.
SU PE R V ISE D E R U P T IO N B y W . S. K E L L Y , D .D .S ., Chicago, 111.
F
O R approximately six years, I have had to deal with an increasing num ber of children presenting an inade quate development of the mandible interfering with the eruption of the six permanent anterior teeth. These chil dren come from families with adequate means, and have , almost all been un der the care of pediatricians since birth. Growth appeared to be normal or above in all cases; the average mentality was high, and there appeared to be less than the average incidence of upper respiratory infections. T h e inadequate expansion of the man dible was producing a malposition of the permanent teeth in these children which would eventually require corrective Jour. A .D .A . & D. Cos., Vol. 24, M ay 1937
measures. As it seemed unethical to per mit these to become corrective cases, I designed two castings which embraced the lingual aspect of the deciduous pos terior teeth up to and including the de ciduous cuspid, no bands being necessary. A lingual spring exerted a gentle, ex pansive force, which augmented normal expansion sufficiently to give each pair of permanent teeth sufficient space. It was found that the point of attachment and the force exerted by the spring must be carefully adjusted, and that the appli ance need only be kept in place for ap proximately the time required for the eruption of each pair of permanent an terior teeth. The overlap of the upper arch made