The effectiveness of three different strengths of chlorhexidine mouthrinse.

: Dental caries in dentate elderly patients may be controlled with chlorhexidine. The purpose of this study is to establish the effectiveness of two low-concentration chlorhexidine mouthrinses in reducing the microbial counts of cariogenic bacteria in a sample of institutionalized elders. Stimulated saliva samples from all subjects before treatment produced counts greater than or equal to 105 colony-forming units (CFU)/mL of lactobacilli and/or mutans streptococci. Treatment consisted of daily rinsing with 4.0 mL of mouthrinse before bed for 14 days. Bacterial counts were re-assessed two weeks after commencing treatment. The mean reduction in mutans streptococci counts in subjects receiving the regular-strength chlorhexidine mouthrinse (Group B) was significantly greater than for subjects using either of the low-concentration rinses (Groups A and C). These findings failed to demonstrate the effectiveness of the lower-concentration mouthrinses (Groups A & C).