ferrule designs and stress distribution in endodontically treated upper central incisors: 3d finite element analysis

objective: the main goal of this study was to evaluate stress distribution of endodonti-cally treated maxillary central incisors restored with glass fiber posts, composite resin cores, and crowns with different ferrule designs. materials and methods: four three-dimensional models of a maxillary central incisor were modeled in solidworks 2006. tooth with no ferrule, tooth with a 2 mm circumferen-tial ferrule, tooth with a 2 mm beveled ferrule and tooth with a 0.5 mm circumferential ferrule. the teeth were restored with glass fiber posts, composite resin cores, and full ce-ramics crowns. each model was loaded (1 n) on the palatal side at an angle of 45 degrees to tooth long axis. von mises stress findings along the inner surface of the root canals were assessed and compared. results: the von mises stress at cej was the highest in the model without a ferrule when compared to the other models (without ferrule 0.0696, short ferrule 0.0492, cylindrical fer-rule 0.0248, and beveled ferrule 0.0387 mpa). conclusion: endodontically treated maxillary central incisors with a ferrule length vary-ing between 0.5 mm and 2.0 mm exhibit lower stress distribution compared to those with-out a ferrule. keeping a long ferrule is suggested to decrease the stress at the cervical area of restored teeth.