Evaluation of Stress Distribution in Endodontically Treated Premolars Restored with Two Different Designs of Overlay Restorations: A Finite Element Analysis

Background fracture of the tooth is the most common drawback of endodontic treatment. It occurs due to weakening of the tooth as the result of dehydration and loss of a great part of tooth structures. One of the treatment options is Indirect partial coverage restoration. different designs and materials of overlay restorations allow favorable distribution of stresses on the restored tooth. Finite element analysis (FEA) is one of the methods used to measure these stresses. Therefore the aim of this study was to evaluate distribution of stresses in endodontically treated premolar restored by overlay restoration with two different designs using FEA Methods Two 3D models of the maxillary premolar were modeled and used. Preparations consisted of MOD cavities with access cavity and tapered root canal preparation, two different designs of overlay restoration were modeled and restored by hybrid ceramic overlays. Stress distribution was evaluated after load application using finite element analysis (FEA) method. Results Oblique loading resulted in much higher stresses than vertical loading in restoration, enamel and dentin. Under vertical loading butt joint design showed better distribution of stresses in both enamel and restoration and more stresses concentration in dentin than concave beveled design. Under oblique loading concave beveled design showed favorable distribution of stresses in restoration, enamel and dentin than butt joint design. Conclusion Butt joint design showed better stress distribution under vertical loading while concave beveled design showed better stress distribution under oblique load.