Fracture Resistance of Endodontically Treated Teeth after Peri-Cervical Dentin Reinforcement: An ex Vivo Study

Loss of peri-cervical dentin (PCD) during root canal preparation may compromise the biomechanical integrity of endodontically treated teeth (ETT). Reinforcement strategies may enhance the ETT fracture resistance. The aim of this study was to evaluate the fracture resistance and fracture patterns of ETT following restoration of prepared PCD with different materials after thermocycling and dynamic loadings.

A total of 48 extracted human single-rooted premolar teeth were equally assigned to four groups (n=12): control (no PDC preparation), resin composite, polyethylene fibers (Ribbond), and gutta-percha. Following standardized root canal treatment, the PCD region was restored accordingly. Samples underwent thermocycling (5-55°C) and dynamic loading (500,000 cycles). The study measured fracture resistance using a universal testing machine. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Fracture mode was assessed using the chi-square test. All statistical analyses were conducted at a 5% significance level.

Fracture resistance differed significantly among groups (p < 0.05). The control group showed the highest values, followed by the Ribbond and resin composite groups, while gutta-percha showed the lowest values. No significant difference was observed between the composite and Ribbond groups (p > 0.05). Compared with the gutta-percha group, the composite group showed a trend toward higher fracture resistance (p=0.052). Fracture mode did not differ significantly (p > 0.05).

Restoration of the prepared PCD region in ETT with either composite resin or Ribbond resulted in fracture resistance values comparable to those of unprepared teeth.