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

Abstract

Aim: This study endeavors to evaluate how various finish line designs impact the marginal adaptation of all-ceramic crowns, which are fabricated using advanced lithium disilicate CAD/CAM material before and after a thermocycling process. Materials and methods: Twenty-Seven human maxillary first premolar teeth were selected for the present study, and they were categorized into three groups, each comprising nine teeth: Group 1 (DCh) featuring a deep chamfer margin design measuring 1mm, Group 2 (Ch) with a chamfer margin design measuring 0.5mm, and Group 3 (Verti) exhibiting a feather-edge margin design measuring 0.2mm. The crowns were constructed from advanced lithium disilicate glass ceramic material. For the cementation process, an adhesive resin cement was utilized to cement the fabricated crowns to their respective teeth. After cementation precise measurements of the marginal discrepancy were taken both before and after the specimens were subjected to thermocycling. To analyze the data, statistical methods such as analysis of variance (ANOVA) and Tukey's post-hoc test, significant difference at (P < 0.05) were used. 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). This was 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 the pair-wise Tukey's post-hoc test, the distinctions between the DCh group and the Ch group were found to be insignificance (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.