Studies on the Numbers of Bacteria in the Mouth and their Reduction by the Use of Oral Antiseptics

Abstract

Tryptose glucose blood agar was found to be an excellent medium for the quantitative estimation of oral bacteria. Tomato juice agar adjusted to pH 5 was suitable for the estimation of oral lactobacilli. The collection of saliva by chewing paraffin for a 3-min. period appeared to be a satisfactory method for obtaining representative samples for the estimation of the oral flora. The numbers of bacteria in the mouth should be based on total numbers of bacteria collected in the samples and not on the numbers per ml. of saliva. The numbers of bacteria in the mouth generally decreased 30-60 min. after each meal. The largest numbers were usually found early in the morning, at noon, and late in the evening. Based on in vivo tests, glycerite of H2O2 and Cepacol generally produced a continual reduction in the oral bacterial flora when used twice daily as a mouth rinse. A marked reduction in the numbers of oral bacteria was obtained when 2 or 3 penicillin troches (5000 U.) were dissolved in the mouth daily, the streptococci being reduced in numbers over 99%.