The authors evaluated the fracture resistance of endodontically treated teeth filled with either gutta-percha or a new resin-based obturation material. The authors prepared and randomly divided 80 single-canal extracted teeth into five groups: lateral and vertical condensation with gutta-percha, lateral and vertical condensation with the new resin-based obturation material, and a control group with no filling material. The specimens were stored in 100 percent humidity for two weeks, mounted in polyester resin and loaded to failure. The authors found statistically significant differences among the experimental groups (P < .05). The groups with the new material displayed higher mean fracture loads and the gutta-percha groups lower mean fracture load values than the control unfilled group. However, the differences were not significant. The groups with the new material displayed significantly higher mean fracture loads than gutta-percha groups independent of the filling technique used. Filling the canals with the new resin-based obturation material increased the in vitro resistance to fracture of endodontically treated single-canal extracted teeth when compared with standard gutta-percha techniques. CLINICAL IMPLICATIONS; If other properties of the new resin-based obturation material compare favorably with those of gutta-percha for filling the root canal, it should be considered as a replacement for gutta-percha, as the results of this study indicate that it could provide enhanced resistance to tooth fracture.