Influence of abutment material and modifications on peri-implant soft-tissue attachment: A systematic review and meta-analysis of histological animal studies

Abstract

Statement of problemHow the properties of the implant-abutment unit may affect the peri-implant soft-tissue seal, whose stability is considered key to safeguarding the implant from bacterial contamination and preserve peri-implant health conditions, is unclear. PurposeThe purpose of this systematic review and meta-analysis of animal studies was to investigate whether material and surface properties of transmucosal implant components can influence the peri-implant soft-tissue adhesion at a histological level. Material and methodsAn electronic and hand search was conducted until August 2019. Histological animal studies comparing soft-tissue response to abutment or transmucosal collar with different materials and/or surface characteristics were selected by 2 independent reviewers. Risk of bias in individual studies was evaluated. Histomorphometric data on the dimension of the peri-implant attachment were recorded, and a quantitative synthesis by a meta-analysis was performed. Risk of bias in individual studies was evaluated in accordance with the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias tool. ResultsEighteen relevant studies out of 1187 were identified, none with a low risk of bias for all domains. Data from only 4 studies could be meta-analyzed. Comparable results in terms of peri-implant attachment dimensions between test and control groups were found, except for a significantly higher apical junctional epithelium to coronal bone to implant (ajE-CBI) distance for chemically modified acid-etched compared with titanium machined surfaces. Non–meta-analyzable and/or qualitative results highlighted some improved properties also for microgrooved and oxidized surfaces. ConclusionsLimited data from animal studies suggest that some characteristics of the transmucosal implant components may affect peri-implant soft-tissue adhesion and stabilization but do not allow definitive conclusions. Future research should improve study design to increase the availability of comparable and suitable data on this topic.