Accuracy of marginal fit of an implant-supported framework fabricated by 3D printing versus subtractive manufacturing technique: A systematic review and meta-analysis

Statement of problem. Evidence comparing additive 3-dimensional printing (3DP) with subtractive milling for implant-supported frameworks is lacking. Purpose. The purpose of this systematic review and meta-analysis was to compare the marginal fit and accuracy of complete arch implant-supported frameworks (CA), implant-retained fixed partial dentures (IRFPDs), single implant crowns (SICs), and interim implant-retained restorations (IIRRs) by using additive manufacturing (AM) and subtractive manufacturing (SM) methods. Material and methods. An electronic search was performed in PubMed, ScienceDirect, Google Scholar, and the Cochrane Library for articles published up to August 2020. The authors acquired the data and evaluated the articles, and the final selection of articles was made according to the inclusion and exclusion criteria. The Methodological Index for Non-Randomized Studies (MINORS) scale was used to evaluate the quality of the included studies. Heterogeneity was evaluated, and meta-analyses with subgroup analyses were performed in the selected studies. Results. The database search resulted in 960 articles. After removing duplicate articles (410 studies), the titles and abstracts were screened in detail, and 10 in vitro studies were selected for qualitative analysis and 9 for quantitative analysis according to the eligibility criteria. Subgroup analyses were performed to compare the 3DP versus the SM technique for different types of implant-supported frameworks (IRFPDs, SICs, IIRRs, and CA). In the IRFPDs analysis, the marginal fit accuracy of the 3DP systems was higher than that with the subtractive manufacturing method (P<.001). In the subgroup analysis of SIC frameworks (P=.55) and CA (P=.67) frameworks, no significant difference was observed in the assessed techniques. Conclusions. The marginal fit of implant-supported frameworks manufactured by AM or SM methods is in the clinically acceptable range. (J Prosthet Dent 2023;129:301-9)