80 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS formula is a pretty low urea, when it is actu- ally used. It is just that when you use a low urea formula, then the result becomes--or the concentration is so dissipated, that we can't see the use. You see, if you analyze the material which is presented to you, you will see that Dr. Kesel's published work was with using con- centrations which were quite similar, if not higher, than my percentages. They are not low. They are higher, if anything. MR. DEN.•v.•RRE: I don't believe I have the answer to my question, but I want to clarify my meaning as to high and low urea. I am using it as it is known in the trade, that is, relative percentages. First let us assume that the dentifrice is used straight in your recommended fashion, applied to the teeth, coming in contact with the oral mucosa. What I am interested in knowing is, have any tests been made, over a period of time, on the effect of your percentages of urea on the oral mucosa after prolonged use ? DR. HENSCI•gL: Every day I see several dozen people--at least a dozen people every day, let me say, who are using these so-called high urea percentages--and the mouths look slick--they are quite fine and healthy--and you may look at mine later, or my wife's. There are a number of people here who have been using it for many years. We are quite normal--I have thirty-two teeth--the tis- sues-the hard tissues and the soft tissues-- are excellent--and there was a time, sir, when we were experimenting with this, when I cleaned my teeth with 40 to 50 per cent solutions of urea, not twice or three times a day, but fifty times a day, and--to say that I lived--well, is it an understatement? CI•A•R•AN: Thank you very much. Dr. Klarmann. DR. KL.•P.•,•: There seems to be a clash of two theories if I get these things straight. According to Dr. Kesel's hypothe- sis, we have in the mouth an equilibrium, a bacterial equilibrium of the acidogenic versus the ammonifying flora, so that we are en- deavoring to support the activity of the ammonifying and suppress that of the acido- genic material. Thus, as a general premise, it would seem inadvisable to incorporate an antiseptic in a toothpaste so long as one would not know which of these two bac- terial floras one is inhibiting, unless of course one has established that the antiseptic would suppress only the acidogenic and not the proteolytic flora. Dr. Henschel made no reference at all to the over-all suppression of the bacterial flora one way or the other, although we know that the tooth paste which is associated with Dr. Henschel's name in the trade bears on the label the declaration that there is incorpo- rated in it a substance which I believe is antiseptic. My question is, then, is this antiseptic there with the purpose ofeffecting a specific reducing action upon the acidogenic flora of the mouth, or is it there for any other reason ? DR. HENSCI•EL: This report concerns the powder and not the paste. As yet, there is no work to report on the paste. There seemed to be a demand for a paste, so the manu- facturers produced one. I believe the anti- septic has other reasons for being in the paste as well as those that you suspect. Possibly Mr. Lewis may have something to say on that. MR. LEw•s: I think I can answer that question. We required a preservative, but we also felt that a fungicide and bactericide were desirable, therefore a chlorophenyl de- rivative was used. It is a bactericide as well as a fungicide and we believed that this would be therapeutically valuable as there are many other organisms which may have greater etiologic implications than Lactobacilli. It was our desire to reduce the numbers of all of these organisms as much as possible. It is, of course, impossible to sterilize the mouth and keep it sterile for any great length of time. I noted an article in Lzfe magazine in September sometime, which was most interesting. Animals raised under sterile conditions, without any bacteria in their environment or body, were reported not to require the intestinal bacteria to synthesize their vitamins and most remarkably, these animals showed no tooth decay and no con- trols are mentioned. As to the question of the necessity of oral

LACTOBACILLUS TEST IN CONTROL OF DENTAL CARIES 81 bacteria in human metabolism, it appears that there are no oral organisms essential for human metabolism. C•A•P. MA•: Are there any other com- ments ? MP.. LEw•s: May I also answer the ques- tion on the "t" correlation of the statistics of this paper. I was privileged to do a sta- tistical study on this particular report and found that the "t" figure between the test and control group was 5.62, a level of signifi- cance of about 1 chance in 100,000 that the results could be similar. There is no statisti- cal question that the difference between the test and control groups is real and significant. (Unfortunately, further discussion was not legible on the wire recm&ng. As a result additional remarks by Drs. Hill and Kesel, as well as the summaries by all three con- tributors to the symposium cannot be printed.--Editor.) THE ROLE OF THE LACTOBACILLUS TEST IN THE CONTROL OF DENTAL CARIES* By PHILIP JAY Professor of Dentistry, School of Dentistry, University of Michigan, /inn/lrbor, Mich. ONE OF THE MOST trouble- some aspects of dental caries re- search is the difficulty of evaluating dental caries activity. Because of its chronic nature, it is necessary to conduct consecutive clinical exam- inations several months apart in order to determine the progress of this disease. It is not possible to recognize caries activity in a single clinical examination. With the greatest scrutiny it is merely pos- sible to determine the extent of tooth destruction which has already, taken place. It is for this reason that.a laboratory test is extremely important. The Lactobacillus counting method has been useful since it has been shown by various investigators that gram positive acid producing rods may be demonstrated on tooth * Presented at the December 5, 1950, Meeting, New Ycrk City. surfaces and in the saliva from six to eighteen months before new carious lesions can be demonstrated clini- cally. As far back as 1907 Goadby, and in 1915 Kligler, associated Lactobacilli with carious lesions. Since that time Mcintosh, Rodri- guez, Bunting, Hadley, Jay, En- right, Arnold, McClure, Becks, and others have shown a diagnostic rela- tionship between the presence of Lactobacilli in the saliva and the de- velopment ofcarious lesions. At the present time the test developed at the University of Michigan is in wide use. Hadley (1) found that a modifica- tion of Kulp's tomato agar produces Lactobacillus colonies which can be differentiated from yeast and vari- ous coccal forms by their colonial characteristics. Most workers have found this method satisfactory, but it must be reproduced in every de- tail.