OBJECTIVETo investigate the stress distribution in dentin of the maxillary central incisor restored with post-core which is related to different shapes and materials.

METHODSCT scan, digital-image processing and Unigraphics (UG) software were applied to construct the three-dimensional finite element models of maxillary central incisor restored with cone or column post-core. Based on this model, stress distribution of Von Mises in dentin with three different materials(polyethylene fiber resin, carbon fiber and zirconia) were analyzed respectively. Static loading(100N) was used on the lingual boundary line between upper-one-third and middle-one-third of maxillary central incisor, the direction of the loading was 45 degrees to the tooth long axis.

RESULTSIn posts made of zirconia and restored with column post, the stress distribution in dentin was higher than with cone post (P<0.05). In posts made of polyethylene fiber resin or carbon fiber, there was no significant difference between the two post shapes (P>0.05). The elastic modulus of post-core materials affected the stress distribution, and the higher the elastic modulus was, the higher the stress concentrated.

CONCLUSIONCone post excels column post in higher elastic modulus materials. Using the lower elastic modulus materials possibly can avail to the stress distribution and prevent the root breakage. During the root canal preparation, the dentin around the root neck should be conserved as more as possible, especially the dentin in the labial side.