Bacterial Colonization of the Implant-Abutment Interface (IAI) of Dental Implants with a Sloped Marginal Design: An in-vitro Study

Purpose: The aim of this study is to utilize an in vitro dynamic loading model to assess the potential risk of bacterial invasion into the Implant Abutment Interface (IAI) microgap of dental implants with sloped marginal design. Materials and Methods: Forty implants were divided into two groups (n=20 per group) based on implant marginal design. Group 1 was comprised of implants with Morse-taper connection and conventional marginal design that connected to titanium abutments. Group 2 was comprised of implants with Morse-taper connection and sloped marginal design that connected to titanium abutments. The specimens were immersed in a bacterial solution of E.coli and loaded with 500,000 cycles of 160N using a chewing simulator. Following disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated and cultured under appropriate conditions. Results: Ten out of twenty implants of Group 1 and eight out of twenty implants of Group 2 had IAI microgaps colonized by E.Coli. There was not a statistically significant difference in the mean number of E.ColiCFU detected between implants of Group 1 (mean 19.2, SD 23.6) and Group 2 (mean 12.5, SD18.9) (p>.05). Conclusions: The present study demonstrated that implants with a sloped marginal design exhibited similar risk for bacterial invasion into the IAI microgap under in vitro dynamic loading conditions compared to implants with conventional marginal design.