Comparison of marginal and internal adaptation in the monolithic crowns produced using traditional and digital impression techniques

Purpose: The purpose of this study was to compare the marginal fit and internal adaptation of monolithic crowns produced different impression techniques in fixed dentures Material and Method: In order to exemplify the main model, tooth number 11 was prepared on the phantom model in accordance with the cutting principles. Monolithic crowns were produced from three different materials using two different impression techniques on this main model. A total of 60 monolithic crowns were produced, 20 from each material group. Group 1; Monolithic zirconium crown manufactured using conventional silicone impressions. Group 2; Leucite-containing glass-ceramic crown produced using conventional silicone impressions. Group 3; Lithium disilicate-containing glass-ceramic crown manufactured using conventional silicone impressions. Group 4; Monolithic zirconium crown manufactured using digital impressions. Group 5; Leucite-containing glass-ceramic crown produced using digital impressions. Group 6; Lithium disilicate-containing glass-ceramic crown manufactured using digital impressions. The silicone replica technique was implemented so as to evaluate the marginal and internal adaptation of the frameworks. The measurements for evaluation was carried out by a stereomicroscope (at ×20 magnification). An intergroup comparison was made in concern with the marginal and internal gap obtained from the photomicrographs. Intergroup comparisons were made by using two-way ANOVA test and Tukey's Post Hoc Test (multiple comparison test). As for the differences between the teeth, Independent T Test was carried out. Results were evaluated at a significance level of p<0.05. Results: According to the results of the study, the marginal fit of lithium disilicate crowns was statistically significantly affected by the impression technique (p˂0.05), while the marginal fit of monolithic zirconium and leucite crowns was not affected by the impression technique (p˃0.05). While the internal fit of monolithic zirconium crowns was statistically significantly affected by the impression technique (p˂0.05), the internal fit of lithium disilicate and leucite crowns was not affected by the impression technique (p˃0.05). Conclusion: It was determined that the marginal and internal fit values of all monolithic crowns produced with conventional and digital impressions were within the clinical limit values accepted in the literature. Key Words: CAD/CAM, Monolithic crown, Internal adaptation, Marginal fit, Fixed denture