A Systematic Review and Meta-Analysis of the Influence of Abutment Material on Peri-implant Soft Tissue Color Measured Using Spectrophotometry

Abstract

Purpose: To systematically review the current literature on the influence of abutment material (metal vs ceramic) and soft tissue thickness on peri-implant soft tissue discoloration in partially edentulous patients restored with implant-supported single crowns. Methods: An electronic MEDLINE search was performed to identify randomized controlled clinical trials (RCTs) up to and including March 2017. The search was complemented by a manual search of related bibliographies. Selection of studies was made independently by two reviewers based on the inclusion criteria. Spectrophotometric data (Delta E values) and soft tissue thickness values were extracted, and, whenever applicable, a meta-analysis using a random-effects approach was performed. Results: The search resulted in 208 titles and 30 abstracts. Full-text analysis was performed for 13 articles, resulting in 6 included RCTs. Meta-analysis of a total of 266 abutments revealed significantly lower Delta E values for ceramic abutments when compared to the overall metal abutments (z test value = 1.99, P =.05), with a mean difference of 1.41 (95% CI 0.02, 2.80). Nonsignificant differences were found between titanium and zirconia (z test value = 1.59, P =.11). Limited information on the correlation between soft tissue thickness and Delta E values was found. Hence, it was not possible to perform a meta-analysis of this question. Conclusion: The color outcome of the peri-implant soft tissue might be influenced by the abutment material. Ceramic abutments appear to provide an improved color matching between peri-implant soft tissues and soft tissues around natural teeth when compared to metallic abutments. These findings support the preference for all-ceramic or "white" abutments in esthetically demanding cases.