"the effects of post diameter on stress distribution in maxillary central incisor, a three dimensional finite element study "

statement of problem: currently there are three recognized theories about the diameter of prepared dowel space in endodontically treated teeth. diameter of the dowel is commonly contributed to the root fracture. purpose: this study used a 3 dimensional (3d) finite element method to predict stress distribution in endodontically treated central maxillary tooth with cast post and core with various post diameter according to three philosophies about post diameter (conservational, proportional, preservational). materials and methods: in this study three 3d models of central maxillary incisors with different post diameter were created and depend on the size of post called narrow, medium and thick model with post diameter of 1.1mm, 1.7 mm and 2.6 mm of in (cej) respectively. a load of 100 n was applied to cingulum fossa from lingual direction with 45-degree angle to long axis of tooth and maximum tensile, compressive and von misses stresses and their distribution in dentin and post was studied. results: the post in narrow, medium and thick models produced a similar magnitude of tensile, compressive and von misses stresses in dentin. stress distribution was also similar in all models. peak stresses in dentin were slightly decreased when post diameter increased from narrow to thick model. in all models peak tensile stresses in dentin occurred in the coronally one third of the lingual surface of the root, whereas peak compressive stresses were evident in the coronal one third of the facial surface of the root. conclusion: there were not significant differences stress distribution pattern and magnitude in dentin between the three theories of post diameter