Evaluation of the Effect of Furcation Perforation on the Fracture Resistance of Endodontically Treated Mandibular Molars

Background: Root perforations are among the most common procedural complications during root canal treatment; these complications have a poor prognosis. This study aimed to evaluate the effect of furcation perforation on the fracture resistance of endodontically treated mandibular molars. Method: Sixty intact extracted mandibular molars were divided into two groups; with a marginal ridge (access only) and without a marginal ridge (MOD and access cavity preparation). The two groups underwent endodontic treatment and were divided into three subdivisions: the first group was prepared without any furcal perforation, the second group had a 1-mm perforation in the furcation area, and the third group was prepared with a 3-mm perforation in the furcation area. The furcation perforation site was filled with calcium hydroxide powder and covered with glass-ionomer (GI). The teeth were restored with posterior composite resin. The teeth were then mounted in acrylic blocks and tested with a Testometric machine under compressive strengths. The fracture resistance diagram of each tooth was drawn. The data were analyzed with two-way ANOVA. The fracture patterns were evaluated after separating the teeth from acrylic blocks. Results: Loss of marginal ridge had no significant effect on fracture resistance measurements (P=0.312), but the furcal perforation variable resulted in significant differences in fracture resistance measurements (P=0.004). Teeth without furcal perforation differed significantly from the teeth with a 3-mm furcal perforation in fracture resistance (P=0.009). The 1-mm furcal perforation group differed significantly from the 3-mm furcal perforation group in fracture resistance (P=0.011). Conclusion: The teeth with a 3-mm furcal perforation exhibited lower fracture resistance than the two other groups.