Evaluation of the Marginal Fit of Single Crowns Fabricated from Digital and Conventional Impressions: An In Vitro Study

Background and objectives: Intraoral scanners replace traditional dental impressions offering more comfort and precision. This research intends to evaluate the discrepancies in the marginal gaps of single crowns produced using traditional impression techniques versus digital intraoral scanners. Methods: This in vitro study was conducted over a one-year period from Sep 2023 to Sep 2024. The clinical procedures were carried out at Shorsh dental center in Sulaymaniyah. Fifteen extracted premolars were prepared for crowns and mounted on a 3D-printed model. Using conventional polyvinyl siloxane and intra-oral scanning with Medit i700, fifteen monolithic zirconia crowns were produced for each technique utilizing computer-aided design/computer-aided manufacturing. Marginal adaptation was assessed using the replica technique with silicone materials. The marginal gap was calculated by determining the distance from the edge of the crown to the finish line margin at four different angles: buccal, palatal, mesial, and distal, then examined under a stereomicroscope, and analyzed with ImageJ software. Results: The average mean of marginal gap in digital impression was (107µm) while in conventional impression was (173µ) and the difference was statistically significance with a p-value (0.033). When comparing each aspect separately there were a significant difference in the palatal, distal, and buccal aspects, p-value was (p = 0.004, p = 0.024 and p = 0.039) but not in the mesial aspect (p = 0.2). Conclusion: The marginal gap was less in digital impression compared to conventional and the difference was statistically significant.