Three-dimensional finite element analysis of fiber post-and-core crown and onlay restorations for mandibular first molars

FAN Xu-dong; CAO Tian-yi; YU Dong-ming; LU Yu-meng; SUN Han-tang

doi:10.15956/j.cnki.chin.j.conserv.dent.2025.03.005

Abstract：AIM:To evaluate the effects of post-and-core crown and onlay restorations on the stress distribution of restorations and residual dental tissues,thus providing a scientific basis for the selection and design of clinical restoration options.METHODS:An adult mandibular first molar extracted due to periodontal disease was analyzed.High-resolution scanning was conducted using a Micro CT,followed by the reconstruction of a three-dimensional model using Mimics 21.0 software.The model was then optimized and simulated using 3ds Max 2024 software.Finally,the model was imported into ANSYS Workbench 2020 R2 software for stress analysis.Based on the extent of dental defects,three defect scenarios were simulated:two-wall defects,three-wall defects,and four-wall defects,with each scenario receiving either an onlay restoration or a post-and-core crown restoration.RESULTS:Under vertical and lingual loading conditions,the three-dimensional models demonstrated similar distributions of equivalent stress and maximum principal stress between different restoration methods.Stress was primarily concentrated in areas such as the central fossa,marginal ridges,and cusps.In the three-wall defect models,the onlay restoration group exhibited the highest values of equivalent stress and maximum principal stress under vertical loading;while under lingual loading,the post-and-core crown group showed the highest peak in equivalent stress,with the onlay group showing the highest peak in maximum principal stress.CONCLUSION:①When dealing with large-scale tooth defects,the choice of restoration method significantly affects the stress distribution of the remaining tooth structure.②From the perspective of stress,for three-wall or four-wall defect in the mandibular first molar,priority should be given to post-and-core crown restoration.For two-wall defects,there is no significant difference between post-and-core crown restoration and onlay restoration.