〔Abstract〕 Objective To investigate the effects of different occlusal veneer preparation designs and fiber posts on the fracture load and failure mode of endodontically treated maxillary premolars with pulp-piercing wedge-shaped defect. Methods 60 maxillary first premolars were randomly divided into group A and group B after Root Canal Therapy(RCT)and severe defects(n=30).Group A was filled with glass fiber post and resin core, and group B was filled with resin core only.Then the occlusal veneer(G2),buccal-occlusal veneer(G3)and buccal-proximal-occlusal veneer(G4)were applied to the isolated teeth.The teeth filled with composite resin(G1)and full crown(G5)were set as negative and positive control respectively, with 6 samples in each group.The sample was subjected to 5 000 hot and cold cycles and 20 000 vertical compression load aging.Finally, all the samples were loaded with static load until the sample broke at the speed of 0.5mm/min.The fracture load and failure mode of each sample were recorded. Results Both the fracture load in group A and B was G5>G3>G2>G4>G1,and the fracture load in G2,G3,G4,G5 was significantly higher than that in G1(P<0.05),and there was no significant difference between group A and B(P>0.05).The fracture form of G3 was mostly unbonding of the repair body, which was conducive to re-repair. Conclusion Buccal(occlusal) veneer is the most effective in repairing pulp-piercing wedge-shaped defects.The fiber post could not significantly enhance the fracture load of the pulp-piercing wedge-shaped defects teeth.