In-vitro comparison of fracture resistance and failure patterns of endocrowns versus post-and-core restorations in maxillary central incisors with and without ferrule.

BACKGROUND: Restoring endodontically treated maxillary central incisors is a clinical challenge influenced by the choice of restoration technique. The amount of remaining ferrule also plays a critical role in the tooth’s structural integrity and long-term success. This study aimed to evaluate and compare the fracture resistance and failure patterns of maxillary central incisors restored with different restoration types and preparation designs. METHODS: In this in vitro study, 40 extracted human maxillary central incisors were randomly divided into four groups (n = 10), based on restoration type (endocrown or post-and-core) and ferrule presence (with or without). All samples underwent standardized root canal treatment, preparation, and restoration using CAD/CAM-fabricated zirconia endocrowns and crowns. Specimens were subjected to thermocycling (5000 cycles, 5–55 °C), followed by a fracture resistance test using a universal testing machine, and failure modes were classified as favorable or unfavorable. All data were analyzed using SPSS version 26 by ANOVA and T-test. A significant level was set at 0.05. RESULTS: Samples restored with zirconia endocrowns demonstrated higher mean fracture resistance (538.80 ± 92.63 N) than post-and-core restorations (458.95 ± 224.49 N), although the difference was not statistically significant (P = 0.154). Restoration design significantly influenced fracture resistance, with ferrule groups exhibiting higher resistance (653.00 ± 26.84 N) than without ferrule groups (344.75 ± 107.71 N; P < 0.001). A significant interaction effect was found between restoration type and preparation design (P < 0.001). CONCLUSION: Endocrowns may offer superior fracture resistance and more favorable failure patterns to traditional post-and-core restorations in endodontically treated maxillary incisors, especially in cases with limited remaining tooth structure.