Evaluation of potential CAD/CAM post-crown materials

Objectives: Computer-aided design/computer-aided manufacturing (CAD/CAM) materials have recently been popular in the dental clinics, but information as to their fracture resistance compared to each other as post-crowns with different materials is lacking. The purpose of this study was to compare the fracture resistance of possible one-piece post-crown materials fabricated by CAD/CAM milling with sound teeth.
Methods: Fifty freshly extracted non-carious human central incisor teeth were endodontically treated. The roots were then randomly divided into five groups according to the post systems: the control group was only filled with gutta percha. Monoblock post-crowns were fabricated with four different systems in the other groups: Yttrium tetragonal zirconia polycrystal (YTZ-P); lithium disilicate glass; resin-based nanocomposite (RNC); and polymer-infiltrated-ceramic-network (PICN). The post-crowns were cemented with resin cement and submitted to universal testing at a crosshead speed of 1.0 mm/min. Statistical analysis of the data was performed using one‑way ANOVA and multiple comparison post hoc Tukey tests (α = .05).
Results: One-way ANOVA revealed significant differences between the groups (P <.001). The mean fracture load of YTZ-P (668.87 N) was higher than those of RNC (343.79 N) and PICN (348.78 N). There were no significant differences between lithium disilicate glass and YTZ-P.
Conclusions: Post-crowns fabricated of different materials by a CAD/CAM system performed over average fracture strength bearded by natural anterior teeth.