A Comparative Study on the Fracture Resistance of CAD/CAM–Fabricated Single‐Piece Post‐Crowns

Objectives Recently, CAD/CAM materials have become popular in dental clinics; however, information about their fracture resistance as post‐crowns remains limited. This study compared the initial fracture resistance of potential single‐piece post‐crown materials made with CAD/CAM milling to sound teeth. Materials and Methods Fifty freshly extracted, non‐carious human central incisor teeth underwent endodontic treatment. The roots were then randomly divided into five groups based on the post systems: the control group included teeth filled only with gutta‐percha. Monoblock post‐crowns were made using four different systems for the other groups: LDS (IPS e.max CAD®, lithium disilicate glass‐ceramic), YTZP (inCoris ZI®, Yttrium tetragonal zirconia polycrystal), RNC (Lava Ultimate®, resin‐based nanoceramic), and PICN (VITA Enamic®, polymer‐infiltrated ceramic network). The post‐crowns were cemented with resin cement and tested with a universal testing machine at a crosshead speed of 1.0 mm/min. Data analysis used one‐way ANOVA and multiple comparison post‐hoc Tukey tests ( α = 0.05). Results Significant differences were found between the groups ( p < 0.001). The control group exhibited the highest fracture resistance (749.25 ± 225.02 N). YTZP showed similar resistance to the control ( p = 0.99) and LDS (447.28 ± 168.72 N, p = 0.081), but was significantly higher than RNC (343.79 ± 157.08 N, p = 0.0051) and PICN (348.78 ± 157.44 N, p = 0.0059). LDS, RNC, and PICN did not differ significantly. YTZP experienced more non‐repairable fractures (5/10), while PICN predominantly failed in a repairable manner (9/10). Conclusions All CAD/CAM post‐crowns exceeded functional loads for the anterior region. YTZP and LDS demonstrated greater strength, whereas PICN and RNC, despite being weaker, favored repairable failures—highlighting the importance of balancing strength and clinical manageability.