Primary reservoirs of Streptococcus mutans and their relationship to caries experience in adults with good oral hygiene

Primary reservoirs of Streptococcus mutans were identified in a group of 21 adults with intact dentitions and good oral hygiene by obtaining multiple plaque samples from all available tooth surfaces. Routine cultural methods and a rapid plate scoring method employing a 7-point ordinal scale were used to assess S. mutans levels. Oral hygiene status (DI-S) and caries experience (DMFT and DMFS) were determined clinically. Primary S. mutans reservoirs (high scores) were restricted essentially to the posterior interproximal areas and occasionally in the occlusal pits and fissures of partially erupted mandibular third molars. An anterior to posterior gradient of increasing S. mutans scores was observed for interproximal sites. Oral hygiene scores correlated poorly with DMFT, DMFS and the S. mutans scores obtained for different anatomic locations.