Definitive Abutments Placed at Implant Insertion and Never Removed: Is It an Effective Approach? A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Purpose: To assess whether repeated abutment disconnections and reconnections have any impact on peri-implant bone resorption and soft tissue healing. Materials and Methods: Electronic and manual searches were conducted for English-language articles published up to March 2017 that identified a relation between repeated disconnections of implant abutments (PA group) and prosthetic or implant failures, complications, marginal bone loss (MBL), soft tissue healing, and esthetic evaluation (pink esthetic score [PES]) after at least 1 year of function compared with implants receiving a final abutment at the time of implant placement (DA group). Results: Fourteen articles (535 patients with 994 implants) were selected for qualitative analysis. Six of these were included in the meta-analysis. Five prostheses failed in the PA group and 1 failed in the DA group (P =.1047). Seven biologic complications occurred in the PA group and 6 occurred in the DA group (P =.8121). MBL was significantly less in the DA group (difference, 0.279 mm; P =.000). Greater buccal recession occurred in the PA group (difference, 0.198 mm; P =.0004). The PES evaluation showed no differences between groups (P =.289). Conclusions: Repeated abutment disconnections and reconnections considerably increased MBL and buccal recession. Further studies are needed to confirm these results.