Esthetic CAD/CAM Post-and-cores: A Biomechanical Study Using Four Different Materials

Objectives: To evaluate the fracture resistance (FR) and fracture type (FT) of CAD/CAM post-and-cores manufactured with four different esthetic materials.
Methods: The roots of 40 humans premolars, were endodontically treated, weakened and restored with CAD/CAM posts. The specimens (n=10) were divided according to the material: Polyetherketoneketone (Ceramill PEEK, PK), nanohybrid composite (Brava Block, BR), hybrid ceramic (Vita Enamic, EN) and epoxi-resin reinforced by glass-fiber (Fiber Cad-Post&Core, FC). After fatigue testing (250000 cycles, 50 Newtons, 5 Hz, 36.5^○C) and underwent compression testing (30^○, 1 mm/m). Statistical analysis were done using one-way ANOVA (FR), and Kruskal-Wallis and Dunn (FT).
Results: The FR(N) values were 750.6±191.6 (PK), 595.7±159.3 (BR), 664.2±165.6 (EN), 629.5±85.8 (AN), there was no statistically significant difference among the materials. For FT, PK was the group who showed only core deformation, without post or root fracture involvement. EN (20%) exhibited fractures in the middle third of the root, considered as non-repairable.
Conclusions: Post-and-cores manufactured with the esthetic materials used in this study presented a similar fracture resistance and different fracture type.