Distribution and prevalence of mutans streptococci in the human dentition.

The prevalence of mutans streptococci was determined in 14,859 samples of plaque from all available tooth surfaces in 114 subjects. The clinical examination included location of incipient caries lesions, fillings, and crowns. Mutans streptococci were detected on 40% of all tooth surfaces. The frequency distribution of mutans streptococci and the level of colonization showed a decreasing gradient from molars to incisors for buccal, lingual, occlusal, and approximal surfaces. The location and number of approximal restorations were closely related to the colonization level of mutans streptococci except for second and third molars. Restored surfaces tended to be more colonized by mutans streptococci than sound surfaces, except for occlusal surfaces. A high prevalence of mutans streptococci was found in plaque samples from tooth-colored fillings, especially on buccal and lingual surfaces.