Association of salivary Streptococcus mutans levels determined by rapid detection system using monoclonal antibodies with prevalence of root surface caries.

Purpose: To examine the hypothesis that salivary Streptococcus mutans levels determined by a rapid detection system using monoclonal antibodies are associated with prevalence of root surface caries in a selected population of older adults.

Methods: Oral examinations were performed in 241 elderly people aged over 60 years with at least 10 teeth, and root surface caries were recorded. Populations of S. mutans in saliva were classified into three groups (Low: < 1 x 10(5) CFU/mL; Moderate: < or = 1 x 10(5) CFU/mL, < 1 x 10(6) CFU/mL; High: < or = 1 x 10(6) CFU/mL) using the analyzing kit with species-specific monoclonal antibodies. Stimulated whole saliva was collected; the flow rate and pH value were determined.

Results: About 38% of subjects had at least one decayed lesion (inactive, active, or secondary lesions). Subjects were grouped according to levels of S. mutans into Low (51.5%), Moderate (39.4%), and High (9.1%). Significant associations were observed between inactive, secondary, or total decayed lesions and salivary S. mutans levels by Kruskal-Wallis test (P < 0.05). Multiple ordinary regression analyses demonstrated that numbers of inactive, secondary, and total decayed lesions were significantly associated with S. mutans levels (P < 0.05) independent of age, gender, frequency of brushing, salivary flow rate, or pH value of saliva.