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In the pursuit of this investigation we made micro-photographs of the grits commonly used in tooth powders and pastes and also combinations as found in a number of proprietary preparations. In the process of making these photographs, each powder or paste was shaken up in an excess of water, allowed to stand for about ten minutes and then filtered. The residue was then dried and mounted as for microscopical examination. The degree of enlargement is alike in all specimens, being 400 diameters.

Figures 9 to 19 inclusive include many of the abrasives commonly used, of which the most common is precipitated chalk. There are many grades and qualities of this substance, many of which contain impurities and foreign matter but the better grades have the appearance of fine round amorphous particles of uniform size. Figs. 13 and 14 show the similarity and identity of the so-called French chalk and Talc. There are many mouth preparations which appear to contain Talc in the form of thin plates of considerable size, and which because of their sharpness make them rapid cutters. Cuttle Fish and Pumice Stone are not being used by many manufacturers at the present time altho there are a few preparations on the market which still contain them. Two samples of Pumice Stone are shown in Figs. 16 and 17 for the purpose of comparing the product of the Buffalo Dental Mfg. Co. with that of ordinary stock pumice. Tin Oxide which is largely used in tooth powders to produce a high lustre to the teeth, is found on the market in several different forms. We show two varieties, Figs. 18 and 19, one a sample bought on the market out of stock and the other a preparation made by Merck. It is claimed that this latter preparation is a better polisher than some other forms, which may be accounted for by the fact that it readily absorbes water, as seen in the cut, and the individual particles swell up, giving the whole mass a sticky and pasty con

sistency, which would be expected to be a better polishing agent than the harder varieties.

In the consideration of the proprietary preparations samples were taken from stock packages of each, and an attempt was made to select a portion for our picture which was as typical of the whole as possible. We recognize the fact that it is difficult to judge a whole product by a small sample as the mixture of ingredients may vary in different

batches or even in two ends of the same can. In our examination we detected certain gross differences in these preparations and have attempted to obtain a true and intelligent record of each. Of the powders and pastes which were examined those which contained the coarser forms of abrasives are Pyorrhocide, Lyons Sozodont and Sanitol as shown in Figs. 20, 23, 31, and 32. Of these, Pyorrhocide contains a relatively large amount of a coarse heavy crystaline substance, two particles of which may be seen in the cut. These large substances are imbedded in a filler of a fine powder which seems to be somewhat hydroscopic. There is no evidence of soap as it does not foam on shaking with water.

Lyons contains a definite prismatic crystal with sharp corners. The filler consists of large round substances of irregular shape. which respond to the test for starch.

Among the finer powders Euthymol, Fig. 22 has a much smaller amount of sharp material than the last two, with a filler that is quite hydroscopic and an abundance of soap, while Graves, Fig. 21, contains a considerable proportion of a finer grit incorporated with granules of starch and has little soap.

Colgate, Listerine, Kolynos, Calox, Lilly, Hutax, and Pebeco, as shown in Figs. 24 to 30 are largely composed of fine grits, some of which resemble precipitated chalk and tin oxide. Many of the illustrations are misleading in their

appearance because of the marked hydroscopic property of their particles which cause them to swell up and clump together so that they appear larger than some of the other varieties which are less hydroscopic. This is true in the cases of Hutax and Pebeco. Many of these preparations contain a high percentage of soap. This is especially true of the pastes. Those which contain little or no soap are Pyorrhocide, Graves, Calox and Listerine.

One non-proprietary preparation was examined, which was made after a formula suggested by Dr. J. W. Jungman of Cleveland. It is a powder and was made according to the following formula:

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shows plainly the precipitated chalk and some evidence of the hydroscopic tin oxide.

Figs. 34 to 36 are similar magnification of three products which are made use of by prophylaxis operators in polishing the teeth. It will be seen that both CarmiCleaner and Politor are largely composed of sharp particles which resemble ground silica. They are, however, quite even in their size and much smaller than those which are found in the ordinary forms of pumice stone. Carmi-Lustra is designed as a fine polishing powder but contains a considerable amount of small sharp crystaline like substances which is imbedded in a fine hydroscopic filler.

It must be clearly understood that in a comparative study of a number of preparations such as have been considered, it is not possible to judge of the cutting or abrasive qualities of each by the size and form of their grits alone. It will be found that the cutting properties are influenced by the hardness and sharpness of the particles as much or more than by their size. So that it is possible for a powder having small sharp particles to cut with greater rapidity than one con

taining large masses. The amount of soap which such preparations contain is also a factor of great importance. For instance, by the use of talc and water on the end of the finger, one may quite easily remove the glaze from a pane of glass. But if the talc be mixt with an equal amount of powdered soap such as is used in tooth powders, it is extremely difficult to make an impression on the surface of the glass in this manner. that it becomes evident that a large amount of soap in a dentifrice by its tendency to foam will envelope and cover up the particles of grit, thus partially or wholly preventing their action when used on the brush.


For the purpose of estimating the effect of certain dentifrices the following experiment was made. Six specimens were prepared each consisting of three perfect teeth, arranged as in the jaw and mounted in modeling compound which was carved to simulate the gums and gingival tissues. Modeling compound caps were then fitted over the incisal third of the tooth leaving the middle and gingival thirds uncovered. These sets of teeth were then brushed in a crosswise manner with a medium size tooth brush, using a different preparation in each case. They were each given 10,000 double strokes, which on the basis of 10 such strokes per day would represent the work done in about three years of use. It was recognized that this form of brushing was not ideal or proper, but was alike in all cases and not dissimilar to that which has very common acceptance among a large proportion of the public today. It must also be admitted that the work was done without the influence of mucinous material which would naturally accumulate upon the teeth from time to time, and which would tend to diminish the abrasive action of the dentifrice. But in each case saliva was used as a lubricant and diluent of the paste or powder to be tested.

The first one of this series was brushed

with water and brush alone. The result, as seen in Fig. 37, was a thoro cleansing of the tooth and a slight amount of wear. A similar test was made with vinegar, strength. The effect as seen in Fig. 38 was to reduce the thickness of the enamel about 1-1000 of an inch by actual measurement. In addition to this it left the surface of the enamel in a corrugated condition as shown in the cut, which seemed to indicate an uneven decalcification of the enamel. As a further test of the action of vinegar we subjected one-half of a tooth to vinegar onehalf strength for 30 minutes, at the end of which time it, together with its control were put thru the silver nitrate test. This was done with several teeth with the result in each case that the silver penetrated to a greater depth and to a considerably greater amount in the case of the half which was treated with vinegar. We do not claim that these are conclusive evidence but we feel that there is reason to believe that vinegar in strength will have a decalcifying action upon the enamel of the teeth and aid in its being worn away by the brush.

The next specimen as shown in Fig. 39 was brushed with one of the pastes containing a fine grit. It did not seem to clean the teeth as well as did the water or vinegar, but rather gave them a smeary and yellowish appearance. The result obtained was far from satisfactory.

Figs. 40 and 41 were of teeth brushed with abrasive preparations which resulted in the cutting of deep grooves thru the enamel and into the dentin. They both bore a striking resemblance to the cases of severe "tooth-brush erosion" which are frequently seen in the mouth. The former of these which contained a coarse grit cleaned the teeth without polishing, leaving a dull surface, while the latter which had a fine grit gave the enamel a high polish and a white appearance.

The last of these series was made with the Dr. Jungman formula given above.

The teeth, as shown in Fig. 42 show no wear but have taken on a high polish which is probably due to the tin oxide which it contains.

In concluding this work we feel that dentists should make a more close study of the properties of dentifrices which they are prescribing, and also the needs of the mouths in which they are to be used. In cases in which the saliva is viscous and deposits form upon the teeth with great rapidity making it difficult to keep the mouth clean, then a more abrasive dentifrice might be used to advantage. But in those cases in which the saliva is thin and the deposits few, an abrasive powder or paste is clearly not indicated. Rather should a fine and hydroscopic preparation be employed which will polish and clean the teeth without wear. The results which we have obtained serve also to call attention again to the importance of brushing the teeth in a vertical rather than a horizontal manner. Especially is this

true in the case of the sharp preparations, which would have produced no such pronounced results as seen in the experiment had they been brushed lengthwise of the teeth. Let us then teach the people how to properly brush their teeth and then advise them as to the particular dentifrice which best suits their needs.


The density of the external enamel surface of the teeth is capable of change.

This change may be co-incident with the changes in bodily health and the calcium content of the saliva.

A consolidation of the enamel surface may be induced by continued polishing and rubbing in prophylactic treatment extended over a considerable space of time.

Results so far obtained warrant a further study and investigation of the calcium content of the saliva in its relation to the condition of tooth tissues and their susceptibility to dental caries.



By Herbert L. Wheeler, New York City.


ETTERS from American dentists who are doing such noble work for humanity, at the American Hospital

of Paris reminds us that a few words telling of the efforts of such men as Drs. Geo. Hayes, W. B. Davenport, Isaac Davenport, of Paris, D. O. M. LeCron and C. W. Roberts of London, and others may be of interest to their colleagues in America who are members of the N. D. A.

This hospital was organized with a dental service under the direction of Drs. Hayes and Davenport at the beginning of the war. Under their skillful guidance the dental department began immediately to make its usefulness felt. Supported entirely by voluntary donations from Americans, its service for fractured jaw cases and kindred injuries is not excelled by any hospital in Europe.

Those serving there give their services and support themselves. An object lesson of the willingness of the American to sacrifice both time and money in the cause of his profession when occasion requires it.

With the settling down of the conflict on its western arena, to a system of trench warfare it has been discovered that a large number of those who are wounded in the trenches are shot in the left arm or in the face or jaw. This has increased the demand for dental service far beyond the ability of the available number of dentists to cope with it.

The work of the dental department of the American Hospital of Paris has been of such a character that ten other hos

pitals in Paris have made application to send Jaw Cases to this dental department.

The service was started with one chair, there are now six and six more are to be put in in order to meet the demands made upon it.

These American dentists who are carrying on this noble work are giving their time, while their practise is being neglected. They are not only doing a great service for humanity, they are at their own personal expense, contributing to keep up the standard and reputation of American dentistry abroad.

For this every dentist in America should feel a deep sense of gratitude.

Let us show our appreciation by contributing of our means to help keep up this service.

Last winter the First District Dental Society of New York City, instead of holding its annual banquet, gave a reception at which admission was charged, and the proceeds, some $300.00, was sent to this hospital in Paris.

Money for the dental service should be sent:

For the Dental Department,

American Hospital of Paris,

Ambulance Lycee, Boulevard d'

Neuilly Sur Seine, Paris, France. Unless specified especially, red cross funds do not reach the Dental Department.

San Francisco, Cal., August 29 to September 9, 1915.

(This is only a partial list of the papers, essayists and clinicians.)

The Evolution and Development of the Mandible.

Kansas City, Mo.

...Chicago, Ill.

By Martin Dewey, D. D. S., M. D....... Anomalies in Dental Pulp Structures and their Relation to Clinical Work. By Dr. V. A. Latham..... Research on the Resistance of the Red Corpuscles of the Blood of the Human Gums (normal and pathological) to the Diluted Salt Solutions. By Prof. Anigo Piperno....

. Rome, Italy

A Brief Synopsis of a Paper Entitled An Investigation of Mottled Teeth; an endemis affection not heretofore known.

By Dr. Fred S. McKay, of Colorado, in Collaboration with Dr. G. V. Black,

The Value of Bacterial Vaccines in the Treatment of Pyorrhea.
By Dr. Geo. B. Harris....

Radiograph in Dentistry and Orthodontia.

By. Drs. Brownlie and Ketcham....

The Etiology of Dental Abscesses, Acute and Chronic.
By Thos. B. Hartzell.....

Chicago, Ill.

.Detroit, Mich.

. Chicago, Ill.

. Minneapolis, Minn.

Acidemetris Study of the Saliva and Its Relation to Diet and Caries.
By John S. Marshall.....

...San Francisco, Cal.

..Ann Arbor, Mich.

An Investigation of the Character of the Various Dental Cements.
By Dr. Marcus L. Ward......

Some Regractory Materials Used in Dentistry.

By Dr. Guy Stillman Millberry.....

San Francisco

Report on Dental Clinical Work in the Hospitals, Schools and Prisons in Manila, P. I.

By Lewis Ottofy, D. D. S.....

The Educational Value of Oral Hygiene in the Army.

By Dr. Edwin P. Tignor....

.Manila, P. I.

United States Army

...Columbus, Ohio.

The Agencies in Ohio Co-operating in a General Hygiene Educational Campaign. By Dr. Homer C. Brown....

Hygiene of the Bucco Dental Cavity as an Important Auxiliary for the Prophy

laxis of Incipient Bucco-Pulmonary Tuberculosis.

By Dr. Ernesto A. Dam.....

Bad Root Canal Work-What Shall We Do About It?

By Howard R. Raper, D. D. S.......

.Lima, Peru

Indianapolis, Ind.

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