In vivo effect of four antibacterial agents upon the acidogenicity of dental plaque.

The present study was carried out to compare the effect of chlorhexidine, iodine, alcohol and hydrogen peroxide on the acidogenicity of dental plaque in vivo. Plaque pH changes after application of sucrose were measured before and at various time intervals after the topical application of the agents. The MIC values of the different agents were assessed against plaque bacteria in vitro. The antimicrobial activity of chlorhexidine and iodine were similar whereas alcohol and hydrogen peroxide were less effective in the concentrations employed. The results showed that chlorhexidine 2%, iodine 2%, and alcohol 70% inhibited pH drops for a 24-h period after treatment whereas 3% hydrogen peroxide had no effect. Chlorhexidine 0.2% inhibited acid production to a greater extent than did alcohol 50% and iodine 0.2%. It is suggested that retention of chlorhexidine in plaque may explain the observed prolonged effect.