Digital versus conventional workflow for the fabrication of multiunit fixed prostheses: A systematic review and meta-analysis of vertical marginal fit in controlled in vitro studies.

STATEMENT OF PROBLEM: Limited evidence is available for the marginal fit of multiunit fixed dental prostheses (MFDPs) fabricated with digital technologies compared with those fabricated with conventional techniques. PURPOSE: The purpose of this systematic review and meta-analysis was to answer the following question: Does digital workflow for the fabrication of tooth-supported or implant-supported MFDPs provide better marginal fit than the conventional workflow? MATERIAL AND METHODS: PubMed, SCOPUS, EBSCO, and Web of Science databases were searched for controlled in vitro studies addressing direct comparison of the fit of MFDPs produced with digital or conventional workflows and excluding studies addressing interim restorations, MFDPs on mixed abutments (teeth and implants), or studies in which reproduction of the basic master cast was performed in 1 group. Vertical and horizontal marginal fit were the primary outcomes; meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with subgroup analysis for tooth- or implant-supported MFDPs. RESULTS: Four studies published between 2011 and 2015 met the inclusion criteria and were included in the review. They investigated 3-unit partial fixed dental prostheses, exhibited a high degree of heterogeneity, and reported data only regarding vertical marginal fit. MFDPs fabricated with digital techniques presented a nominally higher vertical marginal discrepancy than those fabricated with the conventional technique, but the mean difference (MD) (19.8 mum, 95% confidence interval [CI]: -12.1; 51.7) has no statistical significance. The same is also applicable to subgroup analysis for a tooth-supported (MD=45.8 mum, 95% CI: -45.4; 137.0) or implant-supported (MD=14.7 mum, 95% CI: -38.6; 68.1) MFDP. CONCLUSIONS: Digital technologies offer a reliable alternative to conventional techniques for the fabrication of tooth- or implant-supported 3-unit fixed partial dentures; additional studies with up-to-date technologies and for prostheses with more than 3 units are recommended to provide stronger evidence.