Evaluating effect of ferrule height, configuration, and post and core approaches on stress distribution of flared root canal: A three-dimensional finite element analysis

Abstract

Introduction: Radicular rehabilitation in cases of flared canals presents a challenge and is influenced by the type of post and the ferrule design. Use of anatomic posts has been advocated in such cases to allow for homogenous stress distribution. Hence, the aim of the present study was to evaluate and compare the effect of ferrule height, configuration, and post and core approaches on stress distribution of endodontically treated teeth with flared root canal by three-dimensional (3D) finite element analysis. Materials and Methods: Thirteen 3D models of single rooted maxillary second premolar were made using the solid works 2014 software. These were divided into four Groups I, II, III, and IV restored with no post, glass fiber, anatomic, and cast post and core, respectively. Group II, III, and IV were further subdivided into four subgroups a – no ferrule, b – 3 mm circumferential, c – incomplete ferrule of 2.5 mm on buccal and 1.5 mm on palatal side, and d – incomplete ferrule of 1.5 mm on buccal and 2.5 mm on palatal side. Load of 200 N at an angle of 45° was applied to buccal and palatal cusps. ANSYS/ABACUS standard solver with Microsoft Windows 10 Professional was used to analyze model data and perform stress analysis around various elements when subjected to occlusal loading in three dimensions. The maximum von Mises stresses were calculated within post, core, cervical, and radicular dentin and distribution at dentin and cement interface and cement and post interface. Results: The minimum stresses were seen in model restored with 3 mm circumferential ferrule with anatomic post and minimal stress was observed with no ferrule and rehabilitation with cast post. The presence of ferrule reduces the stress distribution in all the models. Incomplete ferrule design is associated with high stresses than partial ferrule. Conclusion: Ferrule allows for a uniform stress distribution and also reduces the stresses at the cervical region of the tooth. Palatal ferrule is more important to provide a fracture resistance to tooth as compared to buccal ferrule.