Fracture resistance of endodontically-treated cuspids

The purpose of this in vitro study was to determine the optimum method for treating an endodontically treated cuspid prior to placement of a crown. Sixty extracted human maxillary and mandibular cuspid teeth were divided into groups of 10. In groups A and B, the crowns were removed at the CEJ and post amalgam cores were placed with #5 Paraposts (Group A) and #120 tapered Ticonium Endowels (Group B). The remaining groups received the following treatments: Group C--gutta percha endodontic fillings, Group D--bonded composite (Fluoro-Core) in the access preparations, Group E--#100 Ticonium Endowels, and Group F--untreated control group. All teeth were prepared for and received cemented gold crowns, were mounted in methyl methacrylate and were stressed at 45 degrees to failure in an Instron machine. Mean fracture strengths (Newtons) were: Group A--500, Group B--530, Group C--520, Group D--510, Group E--680, Group F--580. Results indicated that when the coronal tooth structure was removed, there was no statistical difference (P < 0.05) between the Parapost and Endowel core buildup groups. Although Group E (intact crowns+Endowel posts) displayed higher mean fracture resistance than all other groups, there was no statistical difference (P < 0.05) due to the large range.