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.