The effect of implant-abutment connections on peri-implant bone levels around single implants in the aesthetic zone: A systematic review and a meta-analysis

Objective: To systematically review literature about the effect of different implant-abutment interface designs on peri-implant bone level changes, implant loss and mid-buccal mucosa changes around single implants in the anterior maxilla. Reviewing three connection configurations: Platform switched conical (PS-conical); Platform switched parallel (PS-parallel); Platform matched parallel (PM-parallel).

Methods: A detailed search was carried out in Pubmed, EMBASE, Cochrane, Scopus, Open Gray and African journals Online (until December 1, 2020) and was restricted to clinical prospective studies of at least 1 year and with at least 10 human participants. A meta regression analysis was carried out primarily on the pooled peri-implant bone level changes followed by implant loss and mid-buccal mucosa level change. Risk of bias was assessed with RoB 2.0 and ROBINS-I. The manuscript complied with the PRISMA guidelines and was registered in the PROSPERO database (ID: 225092).

Results: A total of 5513 hits gave 44 eligible articles for the analyses. Bone level change did not differ significantly between the two platform switched connections; their bone loss scores were significantly lower than PM-connection. The PS-conical connections have significantly lower implant losses than the PM connection. Mid-buccal mucosa level change was comparable between the three connection configurations. Moderate to high risk of bias was detected in the included studies.

Conclusions: The performance of PS-conical and PS-parallel connection configurations both favored bone loss scores compared to the PM-parallel connection configuration. All three demonstrated mid-buccal mucosa changes that were small and did not differ significantly amongst the groups.