Comparative assessment of the fracture resistance of endocrowns fabricated from three different CAD/CAM ceramic blocks

Objective: This study aimed to compare the fracture resistance of endocrowns fabricated from three different computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials.Methods: A maxillary left first molar of a typodont model was scanned using an intraoral scanner both before and after standardized endocrown preparation. The scan of the prepared tooth was used to fabricate thirty-six identical resin dies through three-dimensional printing. These dies were then assigned to three groups (n=۱۲), each corresponding to a different CAD/CAM ceramic material: IPS e.max CAD, VITA Suprinity, and VITA Enamic. Endocrowns were digitally designed and milled for each group using a CAD/CAM system. They were then cemented onto the resin dies with dual-cure resin cement and subjected to ۵۰۰۰ thermal cycles. A compressive load was applied to each specimen at a ۳۵° angle to the palatal cusp using a universal testing machine until fracture occurred. Fracture resistance values were recorded in Newtons, and failure modes were evaluated by a stereomicroscope. Statistical analysis was performed using the Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests (P<۰.۰۵).Results: A statistically significant difference was found in the fracture resistance among the three groups (P=۰.۰۱). The IPS e.max CAD group exhibited significantly higher fracture resistance compared to the VITA Enamic group (P=۰.۰۱). No statistically significant difference was observed in failure modes across the groups (P>۰.۰۵).Conclusions: Endocrowns fabricated from IPS e.max CAD demonstrated the highest fracture resistance with no cases of catastrophic failure. VITA Suprinity endocrowns showed the second-highest fracture resistance, with only one case of catastrophic fracture.

کلیدواژه ها:

Computer-Aided Design ، dental porcelain ، dental prosthesis ، Dental Restoration Failure ، fracture resistance ، IPS e.max ceram