Finite element analysis of the influence of esthetic posts on incisors

Kwon, Tae Hoon; Hwang, Jung Won; Kim, Sung Hun; Shin, Sang Wan

Abstract

STATEMENT OF PROBLEM: Most posts are metallic, but in response to the need for a post that possesses optical properties compatible with an all-ceramic crown, an esthetic post has been developed. Although there have been many studies about the esthetic post materials, 3-dimensional finite element studies about the stress distribution of them are in rare. PURPOSE: The purpose of this study is to investigate comparatively the distribution of stresses of the restored, endodontically treated maxillary incisors with the esthetic post materials and the displacement on the cement layer on simulated occlusal loading by using a 3-dimensional finite element analysis model. MATERIAL AND METHOD: Four 3-dimensional finite element models were constructed in a view of a maxillary central incisor, a post, a core, and the supporting tissues to investigate the stresses in various esthetic posts and cores and the displacement on the cement layer (Model 1; Cast gold post and core, Model 2; Glass fiber post with composite core, Model 3; Zirconia post with composite core, Model 4; Zirconia post with ceramic core). Force of 300N was applied to the incisal edge and the cingulum (centric stop point) with the angle of 135-degree to the long axis of the tooth. RESULTS: 1. The stresses and displacement on the incisal edge were higher than on the cingulum. 2. The stresses in dentin were the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. 3. The stresses in post and core were the highest in Model 4 (Zirconia post with ceramic core), and the second was Model 1, the third Model 3, and the lowest Model 2. 4. The displacement on the cement layer was the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. CONCLUSION: When a functional maximum bite force was applied, the distribution of stresses of the esthetic post and core materials and the displacement on the cement layer were a little different. It seems that restoring extensively damaged incisors with esthetic post and core materials would be decided according to the remaining tooth structure.