Evaluation of fracture resistance among endodontically treated teeth using constant, variable and guiding taper endodontic file systems

Canal preparation is a critical step in endodontics because it involves removing a significant amount of dentin, which can weaken the root structure and lead to vertical root fractures. Therefore, it is of interest to evaluate the effect of rotary files with constant, variable and guiding tapers on the fracture resistance of endodontically treated teeth, as well as to assess the mode of fracture. Eighty freshly extracted human mandibular premolars were decoronated, simulated for periodontal ligament, embedded in acrylic resin blocks and subsequently instrumented using JIZAI, ProTaper Ultimate and XP-endo Rise systems. After obturation, fracture resistance was tested with a universal testing machine. The results showed that among the experimental groups, XP-endo Rise had the highest fracture resistance, which was statistically significant (p<0.05) compared to ProTaper Ultimate and JIZAI, indicating better preservation of dentin.