Accuracy of Digital and Conventional Implant Impressions in Edentulous Jaws: A Systematic Review and Meta-Analysis of In Vitro Studies

Objectives: Digital impression-taking techniques are widely used due to their many advantages. However, the accuracy of intraoral scanning in full-arch cases remains a matter of debate. The reliability of different digital implant impression techniques remains questionable in completely edentulous, full-arch cases. This review investigated the accuracy of digital implant impression techniques for full-arch use. Methods: Our study protocol was registered in the PROSPERO database (CRD42023393091). Data reporting was based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines, by the Cochrane Handbook. Comparative in vitro studies matching the PICO framework were included. A systematic search was conducted in four databases: PubMed (MEDLINE), EMBASE, Web of Science and the Cochrane Library (Cochrane Central Register of Controlled Trials [CENTRAL]). Results: Thirty-four papers were included in analyzing trueness and precision of root mean square (RMS) deviations. No significant differences were observed between test groups. The overall RMS trueness deviation was 53.36 μm [18.44; 88.28] in the extraoral stereophotogrammetry group, 73.88 μm [36.68; 111.09] in the conventional impression group, 99.54 μm [56.22; 142.86] in the IOS plain group, 104.88 μm [36.86; 172.90] in the IOS scanaid group, and 65.58 μm [5.24; 125.92] in the IOS splinted group. Substantial heterogeneity was observed across studies (I2 ≈ 100%) Conclusions: In case of completely edentulous jaws restored with four to eight implants, digital techniques showed comparable accuracy to the conventional method with no statistically significant differences detected.