Comparison of the antibacterial efficacy of calcium hydroxide and Nanoparticle Calcium Hydroxide combined with chlorhexidine on Entrococcus faecalis_ an invitro study

Abstract

Introduction: Failure to completely disinfect the root canal system may lead to treatment failure and persistent apical periodontitis. This in vitro study investigated the time-dependent antibacterial efficacy of calcium hydroxide nanoparticles, calcium hydroxide, and their combination with chlorhexidine against Enterococcus faecalis. Materials and Methods: In this in vitro experimental study, 100 sterile paper cones No. 50 were immersed in Enterococcus faecalis microbial solution for 5 minutes. Then, the paper cones contaminated with microbes were placed in sterile containers and covered with 5 types of paste-like mixtures. The paste mixtures consisted of 5 groups (1- calcium hydroxide with distilled water, 2- calcium hydroxide with chlorhexidine, 3- calcium hydroxide nanoparticles with distilled water, and 4- calcium hydroxide nanoparticles with chlorhexidine, 5- normal saline (positive control)). At times 1, 2, 3, and 7 days, the paper cones were removed from the containers and placed individually in test tubes containing BHI broth microbial culture medium. The effects of microbial growth were evaluated by examining the formation of turbidity in the culture media. For analysis, SPSS24 software and independent t-tests, ANOVA analysis of variance were used to compare the turbidity of the samples (microbial growth) among the groups, and the repeated measures test was used to compare the turbidity during the studied times. The significance level in all tests was considered to be less than 5%. Results: All the studied groups showed antibacterial properties within one week and the amount of Enterococcus faecalis decreased significantly within one week. The addition of chlorhexidine significantly increased the antibacterial properties in both types of calcium hydroxide and calcium hydroxide nanoparticle combinations. Calcium hydroxide nanoparticle significantly increased the antibacterial properties. Calcium hydroxide nanoparticle and chlorhexidine had no significant effect on the antibacterial properties. Conclusion: Calcium hydroxide nanoparticle increases the disinfectant properties, but the effect of chlorhexidine is greater than that of nanoparticles.