An in vitro study of a novel chitosan hydrogel blocking agent to prevent microbial leakage via abutment screws of dental implants

Microbial leakage at the implant–abutment–screw interface contributes to biological and mechanical complications in dental implant therapy. A novel chitosan hydrogel (Chitosan-Na 2 CO 3 , CS) against Candida albicans and Enterococcus faecalis to prevents microbial leakage at the implant-abutment interface This study was conducted as a preliminary pilot experiment for a large-scale study, with the main purpose of exploring the feasibility of the experimental procedures. Implant analogs were mounted in super anhydrite, fixed screw holes with chitosan gel sealant and chlorhexidine versus a control group with no treatment. A mechanical torque meter at 20 Ncm was used to tighten the abutment screws. Implant-abutment-screw complexes were cultured with C . albicans and E . faecalis at 37 °C for 7 and 14 days. The rinsed solution was collected and grew on coated agar plates at 37 °C for 24 h. Biofilm formation were observed by microbial counting to assess the efficacy of the chitosan sealant and chlorhexidine (CG) to prevent microbial penetration and inhibit C . albicans and E . faecalis bacterial growth. On day 7, the amount of C . albicans was not significantly greater in the control group than the experimental group ( p = 0.317). On day 14, bacterial growth of the test groups (RC + CS vs. RC + CG) showed no obvious difference compared to the control groups ( p = 0.796). On day 7, there was not significant difference in the growth of E . faecalis between the chitosan and control groups (RN + CS vs. RN + CO) as well as between the chlorhexidine and control groups (RN + CG vs. RN + CO) ( p = 0.317). On day 14, the same pattern was observed in the RN group. Chitosan hydrogels show potential for preventing microbial leakage at the implant-abutment interface, and they seem feasible for further large-scale experiments. Using chitosan hydrogel to prevent microbial leakage at the implant-abutment interface is feasible, and it can provide an estimate of effect size before large-scale clinical trials, guiding future in vivo studies.