OBJECTIVEThis study aims to compare the fracture resistance of teeth restored with different post and core systems by cyclic loading test and to predict long-term effects.

METHODSA total of 15 recently extracted mandibular premolars without crowns were endodontically treated. The teeth were randomly divided into three groups with five teeth in each group. Group A, teeth restored with cast metal post and core. Group B, teeth with fiber post and resin core. Group C, teeth with resin filling. All of the teeth were restored with full-cast metal crowns. The specimens were exposed to 300,000 cyclic loadings in a cyclic loading machine and 1,000 thermal cycles between 5 and 55 °C. All of the samples were loaded in AG-IS mechanical testing machine with a compressive load until fracture occurred. The fracture load and the fracture mode of each tooth were recorded.

RESULTSThe fracture resistance in group B and C were higher than that of the cast metal post and core restoration (P < 0.05). Repairable fractures were observed in group B and C, whereas unrestorable and catastrophic fractures were found in group A.

CONCLUSIONFiber post and resin filling is a good choice to restore endodontically treated teeth.