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.