Three-dimensional finite element analysis of a maxillary central incisor restored with different post-core materials

Xiao-na Li, DDS, PhD,(a) Yun-kai Shi, MSD,(a) Zhen-chun Li, MSD,(a) Chao-ying Song, BDS,(a) Xiao-dong Chen, MSD,(a) Zhen-qun Guan, MSc,(b) Hong Guan, PhD,(c) and Xiang-tao Chen, BDS(d)

(a)Department of Prosthodontics, Dalian Stomatological Hiospital, School and Hospital of Stomotology, Dalian University,(b)Key Laboratory of Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, P. R. China, (c)Griffith School of Engineering, Griffith University Gold Coast Campus, Queensland, Australia, and (d)Department of Prosthodontics, College of Stomatology, Jiamusi University, Jiamusi, P. R. China

Purpose : To provide a theoretical guidance to post-core choice by analyzing dentinal stress of post- restoration with six types of post-core materials.
Materials and Methods : A three-dimensional (3D) finite element model (FEM) of maxillary central incisor restored with porcelain fused to metal crown (PFM) was constructed using spiral CT scan technology. By comparing the restored incisor with PFM as a control model, the stress distribution pattern in the dentine after post restoration was analyzed upon using six types of post-core materials, cast Ni-Cr alloy, cast titanium alloy, cast gold alloy, glass fiber reinforced composite resin, and polyethylene fiber reinforced composite resin, as well as common composite resin.
Results : Compared to the control model, the maximum principal and von Mises stresses in coronal dentin decreased by 26% and 27.8% respectively, while those in post-apex dentine increased by 152% and 162% respectively in post-apex when cast Ni-Cr alloy was used as a post-core. Significant change in maximum stresses was also found in dentin when the first four restoration materials were used as post-core.
Conclusion : Material with low elastic modulus similar to that of dentin, such as polyethylene fiber reinforced composite, may be more ideal for post restoration with respect to the stress distribution in dentin.(Int Chin J Dent 2008; 8: 21-27.)
Key Words : dentin, elastic modulus, finite element analysis, post-core material, stress.