Effect of Submerged vs Nonsubmerged Implant Placement Protocols on Implant Failure and Marginal Bone Loss: A Systematic Review and Meta-Analysis

Purpose: To compare prosthesis and implant failures and marginal bone loss (MBL) resulting from submerged vs nonsubmerged dental implant protocols. Materials and Methods: Electronic and manual searches of two databases (MEDLINE [PubMed] and Cochrane) were conducted to identify randomized controlled trials (RCTs) comparing submerged to nonsubmerged dental implant protocols. Data were independently extracted by two reviewers, and meta-analyses were performed for the included RCTs. The Cochrane Risk of Bias tool was used to assess the quality of included studies. Results: Eight RCTs were identified, and six were included. Four of the included studies were considered to be at high risk of bias, one at unclear risk, and one at low risk. The meta-analysis for studies reporting MBL revealed significantly more bone loss around submerged implants (I2 = 0%, P = .04; mean difference: 0.12; 95% confidence interval: 0.00, 0.24); however, there were no differences in implant or prosthesis failures between the two interventions. Conclusion: Two conclusions were made: (1) There were no differences between the two interventions regarding implant or prosthesis failures, and (2) submerged implants exhibited statistically significantly more MBL, but this difference was not clinically relevant. These conclusions should be interpreted with caution, since the present review is underpowered and the included RCTs were considered to be at high risk of bias.