A microbiologic study of human fissure plague

abstract — The purpose of this investigation was to study colonization and sequencing of oral microorganisms in human tooth fissures. Five human subjects carried a total of 45 crowns of extracted, fully-impacted third molars which were held in place by means of an intraoral appliance. Each specimen was exposed to the oral environment for 1, 2, 3, 5, 7, 9, 12, 15 or 21 d, and prepared under anaerobic conditions for microbiologic analysis of the fissure content. At day 1 and throughout the time sequence studied, cocci (40–70%), Gram-positive rods (20–40%) and Gram-negative rods (5–9%) constituted the predominant flora. Filaments were scarce and were recovered only from plaque more than 15 d old. Approximately 74% of the recovered organisms were acidogenic. S. mutans was found in the fissures of all subjects, but not in all specimens carried by the subjects. The percentage of S. mutans varied largely within the fissures (0–88.9%). S. sanguis was found in amounts equal to S. mutans in all subjects. Lactobacilli were recovered only in a few fissures and then in small numbers. While veillonella was present in all the fissures examined, neisseria was detected in only two subjects.