Fracture Resistance of Anterior Teeth Restored with Y-TZP and Other Post/Core Systems Using Different Cements

Endodontically treated teeth often lose structural integrity, requiring post-and-core restoration. Advances in materials and CAD/CAM technology have enabled esthetic, custom-made restorations, such as one-piece yttrium tetragonal zirconia polycrystal (Y-TZP). This study compared the fracture resistance of different esthetic post-and-core systems using resin and glass ionomer cements.

One hundred extracted human maxillary central incisors were endodontically treated and restored with five post-and-core systems: one-piece Y-TZP, cast metal (NiCr), carbon fiber, prefabricated zirconia with composite core, and prefabricated zirconia with ceramic core (n = 20). Each group was subdivided according to cement type: resin cement or glass ionomer cement. Specimens were restored with all-ceramic crowns and loaded at 135° until fracture. Data were analyzed using two-way ANOVA (α = 0.05).

Significant differences were observed among post systems and cement types (p < 0.001). The one-piece Y-TZP system showed the highest fracture resistance (1191.0 ± 85.6 N with resin cement), while the carbon fiber system showed the lowest values (375.4 ± 27.9 N with glass ionomer cement). Cement type significantly influenced most groups, except NiCr.

The superior performance of the one-piece Y-TZP system may be attributed to its monolithic structure and high mechanical strength afforded by CAD/CAM fabrication, along with a more precise fit and improved stress distribution, which likely contributed to the enhanced mechanical performance. Resin cement generally enhanced fracture resistance compared with glass ionomer cement due to improved adhesion and retention.

One-piece Y-TZP posts demonstrated the highest fracture resistance. Resin cement generally improves fracture resistance compared with glass ionomer cement.