Objective      To investigate the influence of crown restoration and post crown restoration on the stress state of residual dentine of endodontically treated maxillary central incisor with small defects.       Methods      The three-dimensional finite element models were established by a computer to simulate the oblique load. The three models were sound maxillary central incisor

endodontically treated maxillary central incisor treated by crown restoration

and endodontically treated maxillary central incisor treated by post crown restoration

respectively. The distribution and peaks of Von Mises stress and the maximum stress of the residual dentine were analyzed to investigate the effects of 2 different restorations.       Results      The stress distribution showed homogeneous in the sound tooth

while the stress distribution was changed in both restoration models. The Von Mises stress and maximum stress inside dentine showed significant stress concentration at the lingual cervical margin and the root apex. But the stress distribution inside dentine was similar in the 2 restoration models. The peaks of 2 kinds of stress inside dentine were significantly higher in the 2 restoration models than in the sound tooth. Compared with crown restoration

the Von Mises stress peak of post crown restoration was reduced by 16.25%

but the maximum stress was increased by 30.00%.       Conclusion      The post is not necessary when the crown is used as final restoration for endodontically treated maxillary central incisor with small defects.