The Accuracy of Digital vs Conventional Impression among Patients Receiving Dental Implants: A Systematic Review and Meta Analysis of Clinical Studies

Abstract

Background: The accuracy of implant impressions is critical for achieving passive fitness and preventing biological and mechanical complications. Digital intraoral scanners have emerged as an alternative to conventional elastomeric impressions, but their comparative three-dimensional accuracy in partially and completely edentulous patients remains unclear. Materials and Methods: An electronic search of PubMed, Scopus, and Web of Science was performed. Clinical human studies directly comparing digital and conventional implant impressions in partially or completely edentulous patients were included. Distance- and angular-deviation were pooled. Results: Eight clinical studies were included. In the prespecified random-effects analysis, no significant difference was found between digital and conventional impressions for distance deviation (MD = 1.14 mm; 95% CI, -1.88 to 4.16; I2 = 98.7%) or angular deviation (MD = 0.12 degrees; 95% CI, -3.43 to 3.67; I2 = 97.5%). Fixed-effect estimates were calculated only as exploratory sensitivity analyses because heterogeneity was extreme. Subgroup findings, including lower distance and angular deviation with digital impressions in single-implant cases, should be interpreted cautiously because they were based on few studies and, for angular deviation, a single study. Conclusions: Digital and conventional impressions showed comparable overall three-dimensional accuracy under random-effects models; however, the certainty and generalizability of the pooled estimates are limited by extreme heterogeneity, sparse clinical evidence, and subgroup analyses with limited data. Digital workflows may be clinically useful for single-implant and short-span cases, whereas multi-implant and full-arch cases require individualized technique selection according to arch length, implant distribution, operator experience, and available verification methods.