Effect of Implant-Abutment Connection on Bone Level and Survival: A Systematic Review and Meta-Analysis

Background and Objectives: Macroscopic implant design and features have a critical role in the success of the integration and long-term survival of the implants. Key characteristics surrounding the connection of the implant to the abutment have been seen to impact the marginal bone levels surrounding the implant and therefore impact the survival. This review is to evaluate four configurations of implant to abutment connection and quantify the change in marginal bone levels and survival rates. Method of Review: Electronic search was completed of four major databases and then were reviewed by two blinded, independent reviewers following the inclusion criteria. Data from the included articles was categorized into four implant categories: external hex, internal connection >45°, internal connection <45°, and tissue level and then broken into follow up intervals. Data was extracted for marginal bone levels and implant survival. Findings: Review of the databases resulted in 3,082 screened articles. Ultimately 465 were included in full text review, 270 of which included for synthesis and analysis. Mean marginal bone levels were reported and analyzed for all four implant configurations over the time intervals of short, mid and long term. Implant survival was analyzed and reported for all four implant configurations over the time intervals as well. Statistical data and forest plots to follow in full text. Conclusion: The configuration of the implant to abutment junction in dental implants has a statistical significant effect on changes seen to the marginal bone levels surrounding the implants. Theseeffects can be seen throughout both short, mid, and long term follow up. It was seen that the external hex and internal connection >45° implants performed similarly and that the tissue level and internal connection <45° implants performed similarly.