MARGINAL FIT ASSESSMENT OF CAD/CAM ZIRCONIA CROWNS FABRICATED BY DIGITAL SCANNING OF DIES AND SILICONE IMPRESSION (IN VITRO STUDY)

INTRODUCTION: The accuracy of impressions has an important effect on the marginal adaptation of fixed restorations. Fit is the most significant factor influencing the restoration's durability, retention, and periodontal health. AIM OF STUDY: to compare the marginal fit of CAD/CAM zirconia crowns manufactured using two distinct digital impression techniques. MATERIALS AND METHODS: A typodont tooth in the upper premolar region was prepared to receive a full ceramic crown. A direct scan of the prepared tooth was used to create twenty 3D-printed resin dies. The master dies were divided into two groups at random (n = 10 per group). Group I: scanning the dies digitally. Group II: Digitization of the silicone, scannable impressions. Using cone beam CT, the vertical and horizontal marginal gap were evaluated. RESULTS: Group I had a vertical marginal gap of (119.5 ± 27.0) µm, which was substantially smaller than Group II's (144.8 ± 25.23) µm, and a horizontal marginal gap of (107.5 ± 36.36) µm, which was smaller than Group II's (154.3 ± 49.53) µm. CONCLUSION: Although direct digital scanning was superior to indirect digital scanning in terms of marginal fit, all tested techniques yielded clinically acceptable fit values.