Design: This was a placebo-controlled randomised clinical trial (RCT).
Intervention: An active daily rinse of 0.12% chlorhexidine (CHX) was compared with a similar placebo rinse. Subjects alternated between daily rinsing for 1 month, followed by weekly rinsing for 5 months for 5 years.
Outcome measure: The primary outcome was the probability of transition from a sound to a nonsound tooth (an 'event') in each group, specifically, a transition from a sound surface to a surface that became extracted, filled or decayed. Two secondary analyses were performed: an analysis where surfaces that were extracted without an intervening state of decayed or filled were censored, and an analysis where surfaces that were extracted or filled without ever being called decayed at any time were censored. The primary test statistics for evaluating treatment effects was based on the proportional hazards model.
Results: Over the 5-year course of the study, 273 elders (24.8%) did not complete all five followup visits; 57 (5.2%) died, and 15 (1.4%) became edentate. This was lower than the 10% attrition rate every year that had been projected at baseline. The study failed to identify an effect of regular CHX rinsing on the preservation of sound tooth structure on either the roots or the crowns of teeth in low-income older adults. Caries attack rates and hazard ratios are shown in Tables 1 and 2. No adverse events, including anaphylactic reactions, rashes or gastrointestinal disturbances, were reported by the subjects.
Conclusions: These findings suggest that regular rinsing with CHX does not have a substantial effect on the preservation of sound tooth structure in older adults.