Implant-abutment connection as contributing factor to peri-implant diseases.

Dental implant-supported prostheses are an established treatment modality for the functional and esthetic rehabilitation of partial and/or complete edentulous patients. One of the most essential factors for successful treatment outcomes stems from preservation of the peri-implant bone. Early peri-implant crestal bone loss has been a common observation, coincides with the time period where most treatment manipulations occur and has been considered as a complex multifactorial event. Microbial leakage at the implant-abutment interface has been associated with inflammatory reactions that may jeopardize peri-implant crestal bone stability. Prevention of microbial leakage at the implant-abutment interface is a major challenge in the construction of two-piece implant systems. Changes in the implant-abutment complex design achieved reduction in the magnitude of microbial leakage and/or separation of the implant-abutment interface from the osseous surface. However, it is still unclear if microbial leakage at the implant-abutment interface plays a role beyond the initial crestal bone remodeling, namely on the development of peri-implantitis. Therefore, the aim of this review is to analyze the knowledge available on the integrity of different types of implant-abutment connections and their potential role on the development of peri-implant crestal bone loss and peri-implant diseases.