Comparative evaluation of the effect of different crown ferrule designs on the fracture resistance of endodontically treated mandibular premolars restored with fiber posts, composite cores, and crowns: An ex-vivo study

INTRODUCTION: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve which leads to incorporation of different ferrule designs. AIM: To compare and evaluate the effect of different crown ferrule designs on the fracture resistance of mandibular premolars restored with fiber posts, composite cores, and crowns. MATERIALS AND METHODS: Fifty freshly extracted mandibular premolars were endodontically treated and divided into five groups: Group I - 2 mm circumferential ferrule above the cementoenamel junction (CEJ); Group II - 2 mm ferrule on the facial aspect above CEJ; Group III - 2 mm ferrule on the lingual aspect above CEJ; Group IV - 2 mm ferrule on the facial and lingual aspects above CEJ with interproximal concavities, and Group V - no ferrule (control group) and were later restored with fiber posts, composite cores, and crowns. Specimens were mounted on a universal testing machine, and compressive load was applied at a crosshead speed of 1 mm/min until fracture occurred. RESULTS: The results showed that circumferential ferrule produced the highest mean fracture resistance and the least fracture resistance was found in the control group. CONCLUSION: Circumferential ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post, core, and crown.