Effect of two types of composite fibers on fracture resistance of endodontically treated maxillary premolars

Abstract

The aim of the present study was to evaluate the effect of the use of composite fiber(glass, polyethylene fiber) at the gingival third of MOD cavities on the fracture resistance of endodontically treated premolars. Methods: Forty-five extracted human maxillary premolars underwent endodontic treatment. MOD cavities, 2.5+-0.2 mm thick at the buccal and lingual height of contour, were prepared, with the gingival cavosurface margin 1.5mm coronal to the cementenamel junction(CEJ). Then teeth randomly divided into three groups. In group 1, the cavities were restored with Z250 composite resin (3M-ESPE,USA) without the use of any fibers. In groups 2 and 3, the teeth were restored in the same manner as that in group 1 after placement of glass fiber and polyethylene fiber at the gingival third of the cavities, respectively. Subsequent to thermocycling, the specimens were subjected to compressive force in a universal testing machine. Fracture resistance of the specimence was measured in Newton(N). Data was analyzed using one-way ANOVA and a post hoc Tukey test. Results: There were significant differences in the means of fracture resistance values between the three groups(P=0.001). Statistically significant differences were observed in the fracture resistance between group 2 and groups 1 and 3 (P<0.05). However, the differences between groups 1 and 3 were not significant (P=0.25). Evaluation of fracture patterns revealed that the majority of fracture in all the three groups were un favorable and apical to CEJ. Conclusions: The type of fiber influenced the fracture resistance of endodontically treated human premolars.