AMMONIATED DENTIFRICES 71 have had the fewer areas are left for the future development of cavities. In other words, so many of the vulnerable areas have already been filled or the teeth extracted that they could expect less decay without following any therapeutic ritual. Then, too, most individuals ex- perience a lessening of decay as they grow older. For these reasons we believe it lnadvisable to use indi- viduals as their own controls in a caries study. Yet, the people who have had a severe caries experience are the type who will co-operate in the diligent use of the toothbrush. If they are given a dentifrice that they believe may have therapeutic value they are more likely to brush con- sistently over the required period of time. At least this has been our clinical experience. Therefore, at the conclusion of our period of ob- servation, we did not know how much credit to give the brushing and how much we should allow for the dentifrice. Unfortunately, we did not have a control group that was using a non-ammoniated denti- frice with the same zeal as did those who were getting the powder with ammonia added. In order to get an adequate num- ber of toothbrushing subjects at a highly susceptible age with newly erupted teeth not yet attacked by caries, we decided to go to the grade school population. Here their teeth could be brushed at least twice a day with uniformity under the supervision of the room teacher. We selected children with an age range of 10 to 11 years. Funds for the support of the study were ap- propriated by the University of Illinois and the Illinois State Health Department. Permission to con- duct such a study was obtained from the boards of education in Aurora and Peoria, Ill., and the co-opera- tion of the room teachers was en- listed. We pointed out to them that if we gave the children dentifrice and toothbrushes to use at home we would have no assurance that each would •bllow explicit instructions. Uniformness i.n performance was necessary for comparing the effects of different dentifrices and this re- quired at least two brushings a day under the supervision of the room teachers. The teachers understood this necessity, they were well aware of the seriousness of dental decay in the child population and agreed to give the supervision and the amount of school time necessary for each brushing operation, which is ap- proximately ten minutes, although the actual brushing requires only two minutes. Approximately 1,700 children are included in the study which began almost two years ago. Each child was given a dental prophylaxis by a hygienist since we wished each to start the project with a clean mouth. Following the prophy[axis each child had his teeth examined by a dentist, who was a staff member of the Il- linois State Health Department. This service was requested from the State Health Department as we de- sired to have the clinical data col-

72 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS lected and appraised by an im- partial organization. The dental examination was augmented by full mouth x-ray pictures. The 1,700 children were divided into four groups, two were supplied with dentifrices containing ammonia and one a control dentifrice that had similar composition to the am- moniated except the $ per cent di- basic ammonium phosphate and 3 per cent urea were replaced with additional precipitated calcium car- bonate. The fourth group was de- signed to be a further control and was not supplied with a dentifrice or brushing instructions these chil- dren were requested to follow their customary habits or oral hygiene. The study began in February, 1948, and terminated on Mar. 1, 1950. March, April, and May were used to make the final mouth examinations. The accumulated data were ana- lyzed by the examiners and statisti- cians from the Illinois State Health Department and reported to us in the early summer. No diet regulation, topical ap- plication of sodium fluoride, or other methods for reducing caries activity were given to these chil- dren as we wished to determine only the merits of oral hygiene and an ammoniated dentifrice. We realize that this plan subjected the method to a severe test, par- ticularly in view of the high carbo- hydrate consumption in children, but we wanted to study •he method under the conditions that it would usually be employed. We also know that the extensive advertising cam- paigns for ammoniated dentifrices have contaminated our control group. REFERENCES (1) Easlick, KennethA., Dental Caries, Mech- anism and Present Control Technics, Reports of Evaluating Committees, p. 201, The C. V. Mosby Company, St. Louis, 1948. (2) Kesel, R. G., O'Donnell, J. F., Kirch, E. R., and Wach, E. C., Ammonia Pro- duction in the Oral Cavity and the Use of Ammonium Salts for the Control of Dental Caries, Am. y. Ortho. Oral Surg., 33, No. 2, 80-101, (1947). (3) Wilson, W. J., Pleomorphism as Exhib- ited by Bacteria Grown on Media Con- taining Urea, y. Path. Bact., 2,394 (1906).