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.