One abutment one time vs repeatable abutment disconnections in implants, restored with cemented / screw retained fixed partial dentures: Marginal bone level changes. A systematic review and meta-analysis

Imantas Vatėnas
Tomas Linkevičius


Purpose: The aim of this systematic review and meta-analysis is to evaluate the impact of abutment disconnections / reconnections on peri-implant marginal bone loss changes in partially edentulous patients.
Methods: Clinical studies were selected via electronic and hand searches in English language journals until January 1, 2020. Only randomized clinical trials (RCGTs) and prospective controlled clinical trials (CCTs) showing direct comparison between the definitive implant abutments and multiple abutment replacements in the same patient or different patient groups in the partially edentulous patients were considered. The outcome measures were (1) the type of the abutment was used, (2) the time the abutment was placed, (3) marginal bone loss changes, (4) biological complications, (5) mechanical complications.
Results: After evaluation, 4 controlled clinical studies were included. Majority of the articles reveled protective marginal bone loss preservation for the implants with FAP (final abutment placement) at the time of implant placement compared with the implants with MAP (multiple abutment placements) in connected dental implants, in partially edentulous patients. Meta-analysis of the four studies with 280 implants reviled significantly greater bone loss in cases with multiple abutment disconnections/reconnections. The weighted mean difference in marginal bone loss was 0.4 mm (95% confidence interval, 0.16-0.63 mm), showing bone preservation in the FAP group.
Conclusion: Within the limitations of this meta-analysis, multiple abutments disconnections significantly affected marginal bone loss changes in partially edentulous patients. The finding suggests to overview current prosthetic and surgical treatment planning protocols to prevent greater marginal bone loss.
Keywords: marginal bone loss, final abutment, definitive abutment, abutment level, one abutment one time, final abutment placement, multiple abutment placement, fixed partial dentures.

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