Effect of Different Core Build-up Materials on the Fracture Resistance and Failure Patterns of Endodontically Treated Maxillary Premolars.

INTRODUCTION

This in vitro study evaluated the fracture resistance and failure patterns of endodontically treated maxillary premolars with mesio-occluso-distal (MOD) cavities restored using different core build-up materials.

METHODS

Seventy-two intact human maxillary premolars were randomly assigned to six groups (n = 12). Endodontic treatment and standardized MOD cavity preparation were performed for all groups except the positive control (Group 1). Group 2 served as the negative control (ETT+MOD), whereas the remaining groups were restored with NC, FRC+NC, HFP+NC , or ACTIVA+NC . Following thermocycling, fracture resistance was evaluated using a universal testing machine under compressive loading, and failure patterns were recorded. Data were analysed using one-way analysis of variance and the Tukey post hoc test (P < .05). Fracture-mode data were treated as categorical variables and were analysed using Fisher's exact test.

RESULTS

Fracture resistance differed significantly among the groups (P < .001). The ETT+MOD+FRC+NC group demonstrated fracture resistance comparable to that of intact teeth and significantly greater than ETT+MOD+HFP+NC group (P < .05). No significant differences were observed between the ETT+MOD+FRC+NC and ETT+MOD+ACTIVA+NC groups or between the ETT+MOD+HFP+NC and ETT+MOD+ACTIVA+NC groups (P > .05). All remaining pairwise comparisons were statistically significant (P < .05). Failure-pattern analysis demonstrated a significant difference in the distribution of favourable and unfavourable fractures among the groups where ETT+MOD+FRC+NC group exhibited the highest proportion of favourable/repairable fractures.

CONCLUSIONS

Within the limitations of this in vitro study, the type of core build-up material significantly influenced fracture resistance. FRC+NC group demonstrated the greatest reinforcing effect, whereas ACTIVA+NC and HFP+NC groups showed comparable performance and superior fracture resistance to NC group.