The Role of Chlorhexidine on Endotoxin Penetration to the Implant-Abutment Interface (IAI)

Purpose: The aim of this study is to assess the risk of endotoxin penetration to the implant-abutment interface (IAI) of implants with Morse-taper connection and the effect of chlorhexidine in the prevention of such penetration. Materials and Methods: Thirty implants with Morse-taper connection were divided into three groups (n=10/group) based on type of inoculation of the internal aspect of the implant. Implants in Group 1 were inoculated with 1μl Escherichia coli for 24 hours; supernatant was removed and 0.5μl of sterile saline was added. Implants in Group 2 were inoculated with 1μl E.coli for 24 hours; supernatant was removed and 0.5μl 0.2% chlorhexidine solution was added. Implants in Group 3 were inoculated with 0.5μl of sterile saline and served as controls. Following inoculation procedures, implants were connected to standard abutments, immersed in sterile culture media, and loaded with 200,000 cycles of 160N in a wear simulator. Samples were collected from the supernatant solution of each implant for endotoxin identification at the beginning of the loading cycle (T0) and following 9 hours (T9), 18 hours (T18), 27 hours (T27), 36 hours (T36), 45 hours (T45), and 54 hours (T54). Results: For Group 1 and Group 2, there were statistically significant differences between the endotoxin concentration at T0 and the endotoxin concentration at the subsequent sampling points (p<.05 Kruskal-Wallis with Bonferoni corrections for intragroup comparisons). There were no statistically significant differences between Group 1 and Group 2 at all sampling points. Conclusions: This study indicates that bacterial endotoxin can penetrate the IAI of implants with Morse-taper connection, and 0.2% chlorhexidine solution had no significant effect on that penetration.