Fracture resistance of palatal cusps defective premolars restored with polyethylene fiber and composite resin.

The aim of the study was to compare the fracture resistance of the palatal cusps of defective and endodontically treated premolars after restoration with various restorative techniques. Fifty premolars were assigned to five groups. The first group comprised intact teeth as control (G1), while the other experimental groups (G2, G3, G4 and G5) comprised endodontically-treated teeth, whose palatal cusps were cut and reduced the buccal cusps by 2 mm. G2, composite resin onlay with buccal cusp coverage (CR). G3, CR and fiber post. G4, CR and polyethylene fiber. G5, CR, fiber post and polyethylene fiber. Fracture resistance was tested. The data were recorded in Newton and submitted to ANOVA and Tukey post hoc tests. Statistically significant difference was found between the mean fracture resistances of the groups. Polyethylene fiber reinforced composite restorations strengthened the fracture resistance of palatal cusps defective and endodontically treated premolars.