Reliability of digital measurement methods on the marginal fit of fixed prostheses: A systematic review and meta-analysis of in vitro studies

Statement of problem: Digital methods have been increasingly used to evaluate the fit of prostheses, but the accuracy of digital methodology has not been fully clarified. Purpose: The purpose of this systematic review and meta-analysis was to assess the reliability of digital measurement methods for evaluating the marginal fit of fixed dental prostheses (FDPs) and to identify the potential factors that can influence the accuracy of the measurement methods. Material and methods: The differences between digital and conventional measurement methods were analyzed by searching PubMed, Scopus, Web of Science, and Google Scholar databases for studies reporting the marginal fit of FDPs. The agreement of data collection among the reviewers was confirmed by the Cohen kappa coefficient, and the MINORS scale was used to rate the quality of the included studies. The heterogeneity among the studies was evaluated, and meta-analyses with global and subgroup analyses were performed. Results: Ten in vitro studies were selected according to the eligibility criteria with substantial interreader concordance (κ=0.88). The standard mean difference of the meta-analysis for marginal discrepancy was 0.12 μm (95% confidence interval: -0.12 to 0.35), indicating that no statistically significant differences were found in the marginal discrepancies observed with digital and conventional methods (P=.343). The subgroup analysis for alloy-based prostheses was not significantly different, nor between the material and measurement methods (P=.060). Conclusions: Digital methods appear to be reliable as an alternative to conventional methods for evaluating the marginal fit of FDPs. To confirm the results of this study and to identify the influencing factors on the accuracy of digital measurement methods, further controlled laboratory and clinical studies are needed.