Comparison of Internal and Marginal Adaptation of Endocrowns at Different Depths Fabricated by the Digital and Conventional Impression Techniques: Internal and Marginal Fit of Endocrowns.

Introduction: Sufficient information is not available regarding the comparative accuracy of digital and conventional impression techniques at different depths for the fabrication of endocrown restorations. Thus, this study aimed to compare the marginal (M) and internal (I) adaptation of endocrowns at different depths fabricated by the digital and conventional impression techniques. Materials and Methods: In this in vitro study, two endodontically treated molar teeth with 2- and 4-mm cavity depths were used for the fabrication of endocrowns. Conventional and digital impressions were made from each tooth 17 times. A total of 68 zirconia endocrowns were fabricated and seated, and their I and M adaptation was assessed by the silicone replica technique. Data were statistically analyzed. Results: The M and I gaps at 2- and 4-mm cavity depths were significantly smaller in the digital, than the conventional, impression technique (p  < 0.05). Increasing the cavity depth significantly increased the M and I gaps only in the digital technique (p  < 0.05). The largest gap in all groups was noted in the pulpal (P) region (p  < 0.05). The smallest gap was found in the M and cervical (C) regions in the conventional groups with 2- and 4-mm cavity depths, and the digital group with 4 mm cavity depth, and in the M region in the digital group with 2 mm cavity depth (p  < 0.05). Conclusion: Unlike the conventional impression technique, the M and I adaptation decreased by an increase in cavity depth in the digital technique; nonetheless, the digital impression technique still showed higher M and I adaptation than the conventional technique.