The Effect of Preparation Design on the Marginal Adaptation of Monolithic Crowns Made of New CAD/CAM Ceramic Material An In-Vitro Study

Aim: This study endeavors to evaluate how various finish line designs impact the marginal adaptation of all-ceramic crowns fabricated using advanced lithium disilicate CAD/CAM material before and after a thermocycling process.
Materials and methods: Twenty-seven maxillary first premolar teeth were selected, and they were categorized into three groups (n = 9): Group 1 (DCh) deep chamfer margin design, Group 2 (Ch) with a chamfer margin design, and Group 3 (Verti). The crowns were constructed from ALDs. An adhesive resin cement was utilized to cement the fabricated crowns to their corresponding teeth. After cementation, precise measurements of the marginal discrepancy were taken both before and after subjecting the specimens to thermocycling. (ANOVA) and Tukey's post hoc tests were used to analyze the data for significant differences (P < 0.05).
Results: Before and after undergoing thermocycling, it was observed that the DCh group exhibited the highest mean marginal gap values (64.67 µm, 71.08 µm), followed by the Ch group (52.40 µm, 61.98 µm), whereas the Verti group displayed the lowest mean marginal gap values (41.74 µm, 44.86 µm). This disparity was statistically significant, as evidenced by the one-way ANOVA test results. (p =0.002<0.05). Upon employing pair-wise Tukey’s post-hoc test, the distinctions between the DCh group and the Ch group were found to be insignificant (p > 0.05).
Conclusion: Considering the constraints inherent to this study, when compared to the other groups, the Verti group demonstrated significantly superior marginal adaptation both before and after the thermal aging process.