Fracture resistance of endodontically restored, weakened incisors.

Objectives: To test the fracture strength of weakened bovine incisors endodontically treated with mineral trioxide aggregate (MTA), calcium phosphate bone cement (CPBC) or fibre reinforced composite (FRC) posts, and to evaluate the fracture mode.

Methods: Weakened bovine incisors (n = 75), standardized according to the dentinal wall thickness at the cervical area, were randomly assigned to one control group and three experimental groups. Unfilled teeth were assigned to group 1 (n = 20) and served as control group. Group 2 (n = 17) consisted of teeth filled with MTA. In group 3 (n = 18), the incisors were filled with CPBC and in group 4 (n = 20) with FRC posts. All specimens were subjected to load at a cross-head speed of 60 mm min(-1) until fracture occurred. The initial (IL) and final fracture (FL) loads (N) were recorded, and the failure mode among the different groups was evaluated.

Results: anova showed a statistically significant difference in fracture load among the groups. Tukey's test revealed a significant difference for the IL between the control group and the experimental groups with exception of the MTA group. The FL was not significantly different among the experimental groups. A high percentage of favourable fractures was seen in the FRC and CPBC groups.

Conclusion: FRC posts and CPBC could be promising materials to strengthen non-vital structurally compromised teeth.