Digital versus conventional full-arch impressions in linear and 3D accuracy: a systematic review and meta-analysis of in vivo studies.

OBJECTIVES: The purpose of this systematic review was to compare the accuracy of digital and conventional full-arch impressions in vivo. MATERIALS AND METHODS: This systematic review was conducted according to the PRISMA and registered at the PROSPERO (CRD42021232736). Electronic and hand searches were performed to identify in vivo studies comparing the linear or 3D accuracy of digital and conventional impressions. The risk of bias (ROB) of included studies was assessed by QUADAS-2, and the overall quality of evidence was assessed by GRADE. RESULTS: Twenty-two studies met the inclusion criteria, and 13 studies were included in the meta-analysis. There was no significant difference between digital and conventional impressions in the linear measurements of tooth width, anterior Bolton ratio, overall Bolton ratio, intercanine distance (ICD), and intermolar distance (IMD). The repeated measurement mean errors (RMEs) were less than 0.1 mm, the intra-examiner intraclass correlation coefficient (ICC) values were more than 0.9, and the inter-examiner ICC values were more than 0.87 for both impression techniques. The 3D deviation between digital and alginate impressions was 0.09 mm. The 3D precision of both impression techniques was less than 0.1 mm. CONCLUSIONS: The trueness of digital and alginate full-arch impressions was similar, and both impression techniques showed high precision. More research was needed to compare digital impressions and other conventional impression materials. CLINICAL RELEVANCE: For patients with completely natural dentition, the digital impressions obtained directly from intraoral scanning can be considered a viable alternative to alginate impressions.