Marginal Gap and Internal Fit of Fixed Dental Prostheses Fabricated Using Intraoral vs Extraoral Scanning: A Systematic Review and Meta-analysis.

Abstract

To compare the marginal gap and internal fit of fixed dental prostheses (FDPs) fabricated using intraoral vs extraoral scanning methods. MEDLINE/PubMed and the Cochrane database were searched. The focused PICO question was: For the fabrication of FDPs, does an intraoral scanning technique result in a different marginal gap than an extraoral scanning technique? The secondary outcome assessed was internal fit. Studies were selected based on the inclusion criteria, and a meta-analysis was performed. A total of 14 studies (10 in vitro and 4 in vivo) were included in the meta-analysis. Marginal gap in single crowns was evaluated in 5 studies, copings for single crowns in 5 studies, three-unit FDPs in 3 studies, and both single-crown and three-unit FDPs in 1 study. Significantly lower marginal gap was found with intraoral scanning compared to impression scanning (P < .001) and cast scanning (P < .001), and for impression scanning compared to cast scanning (P = .037). Internal fit was superior with intraoral scanning compared to impression scanning, and this difference was significant (P < .001). No significant differences were found in internal fit with cast scanning compared to intraoral or impression scanning. The mean marginal gap/internal fit was 188.3 μm/146.2 μm with intraoral scanning, 116.29 μm/168.2 μm with impression scanning, and 195.1 μm/229.1 μm with cast scanning. Marginal gap was lower with intraoral scanning than with impression scanning and cast scanning. Impression scanning showed less marginal gap than cast scanning. Internal fit with intraoral scanning was superior to impression scanning, but when compared to cast scanning, no difference was found.