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

Abstract

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. 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 10min (CHX-10min and Pr-10min) or 7days (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. 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-10min (P=0.963) and Pr-7d (P=0.095) revealed no significant differences. Pr-10min had a significantly higher CFU value than Ca-7d(g) (P=0.0004), CHX-10min (P=0.0009) and Pr-7d (P=0.0006). 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 (7day) is required, while short-term use (10min) is less effective.