A study was conducted on 503 children aged 9 attending 2 primary schools in Fukuoka City, Fukuoka Prefecture, for the purpose of evaluating the possible caries preventive potentials of two types of dentifrices containing sodium fluoride and sodium n-lauroyl sarcosinate respectively. The subjects were divided into 3 groups, one receiving sodium fluoride, the other sodium n-lauroyl sarcoainate in respective dentifrice in their daily practice of tooth brushing and the last group being left uninstructed to observe any special oral hygiene to serve as the contrast. The experiment was carried out for full two years from April 1955 to April 1957 and the results were analyzed as to the relative merit of these two types of dentifrices in reducing the caries incidence among the subjects examined. It was shown that the percent reduction in the DMF tooth in subjects receiving sodium fluoride and sodium n-lauroyl sarcosinate were respectively 20% and 22%, indicating that there was no appreciable difference in efficacy between two agents. Better and more clear results might have been elicited from the experiment if the instruction were effected more rigorously to observe the right time and procedure in practicing the tooth brushing.
