A comparative study of stress distribution between glass fiber post and cast post in an endodontically treated central incisor – A finite element analysis

Background: Endodontically treated teeth with severe loss of tooth structure require post and core restorations for retention purposes. The post system includes components of different rigidity because the rigid component is able to withstand forces without distortion and the stress is transferred to less rigid substrate. The difference between the elastic modulus of dentin and the post material may be a source of stress for root structures. The use of post systems that have an elastic modulus similar to that of dentin result in the creation of a mechanically homogenous unit with better biomechanical performance. Thus the post and core material affects stress distribution in endodontically treated teeth.Aims and Objectives: In this study, FEA is used to evaluate the fracture resistance in an endodontically treated maxillary central incisor that was restored with two different post systems – 1) prefabricated glass fiber post and 2) custom made cast post. The qualitative stress distribution analyses were recorded by von Mises criteria. Results: von Mises stress in an intact tooth was concentrated in the crown near the cingulum under oblique load and on the incisal edge with vertical load. With horizontal load- In the crown region, maximum von Mises stress was observed in both the cast post and fiber post. Within the post region, maximum von Mises stress was observed in cast post when compared to fiber post. In the root dentin, more von Mises stress was observed in fiber post when compared to cast post. Conclusion: 1)Stress distribution is similar between cast post and fiber post during vertical load. 2)Cast metal post dissipates less stress to the dentin and gives better fracture resistance to the tooth when compared to glass fiber post during oblique loading. When considering the stress pattern, maximum stress was observed in the cervical region of the crown and in the area of load application during oblique and vertical loading.