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=12), 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 5000 thermal cycles. a compressive load was applied to each specimen at a 35° 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<0.05).results: a statistically significant difference was found in the fracture resistance among the three groups (p=0.01). the ips e.max cad group exhibited significantly higher fracture resistance compared to the vita enamic group (p=0.01). no statistically significant difference was observed in failure modes across the groups (p>0.05).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.