Streptococcus mutans, lactobacilli, and caries experience in older adults.

This study investigated salivary levels of Streptococcus mutans, lactobacilli, and caries experience in a random sample of 448 black and 362 white older dentate adults living in North Carolina. Significant proportions of the participants had stimulated salivary flow rates less than 1.0 mL/min, salivary buffering capacity less than 4.0, S. mutans levels of 10(5) cfu/mL or more in stimulated whole saliva, or lactobacilli levels of 10(5) cfu/mL or more. Each of these factor levels could be considered, on a clinical basis, to increase caries risk. In general, people with higher levels of S. mutans or lactobacilli had more untreated coronal and root caries, but not greater total caries experience.