Antimicrobial activity of short- and medium-term applications of polyhexamethylene biguanide, chlorhexidine digluconate and calcium hydroxide in infected immature bovine teeth in vitro.

ABSTRACT

AIM: To compare the antimicrobial activity of polyhexamethylene biguanide (Prontosan wound gel, Pr) and chlorhexidine digluconate (CHX) after short- and medium-term application with the disinfection ability of calcium hydroxide (Ca) in a model using immature bovine teeth. METHODS: Sixty immature bovine roots were infected with Enterococcus faecalis and randomly assigned to six groups (n = 10). Disinfectants were applied into the root canal for 10 min (CHX-10 min and Pr-10 min) or 7 days (CHX-7d, Pr-7d and Ca-7d(g) ). In the negative control group (Co-n), no disinfectant was used. Dentine samples were collected, and the total count of bacteria and colony-forming units were determined. The log10 -transformed Colony-forming units (CFU) data were analysed using a Kruskal-Wallis test with post hoc Wilcoxon multiple-comparison tests. RESULTS: The application of disinfectants led to a significant reduction in CFUs in all groups compared with group Co-n. When compared to Ca-7d(g) , CHX-7d (P = 0.290), CHX-10 min (P = 0.963) and Pr-7d (P = 0.095) revealed no significant differences. Pr-10 min had a significantly higher CFU value than Ca-7d(g) (P = 0.0004), CHX-10 min (P = 0.0009) and Pr-7d (P = 0.0006). CONCLUSIONS: Within the limitations of this study, sufficient antimicrobial effect may be reached by a short-term application of CHX. For the application of 1% Prontosan wound gel, a medium-term use (7 day) is required, while short-term use (10 min) is less effective.