In Vitro Analysis of the Implant-Abutment Interface Connection and Bacterial Infiltration in Two Extraoral Implant Models

Purpose: To compare the connection microgaps and the bacterial infiltration of implant-abutment interfaces of two extraoral implant models. Materials and Methods: Two implant models were used: the inner connection and the flush connection types. The implant-abutment microgaps of five sets of each extraoral implant were evaluated with scanning electron microscopy. Eleven additional sets of each model design were immersed in Staphylococcus aureus cultures for 24 hours, and samples were obtained from the external surface and from the implant's internal chamber to quantify the colony-forming units. Results: Scanning electron microscopy analysis showed that microgaps of the flush connection were smaller compared with the inner connection (P .0001), and that bacterial counts were higher at the inner connection compared with the flush connection (P .0001). Conclusion: Within the limitations of this experimental study, it can be concluded that the flush connection model presented a smaller microgap and fewer bacterial colonies compared with the inner connection model. Keywords: extraoral implants, implant-abutment interface, microbial leakage