Finite Element Analysis Study of Endodontically Treated Molar Restored with 4 Chairside CAD/CAM Restorations

Objective: To compare stress distribution in each area of the mandibular first molars after root canal treatment with four different types of restorations and conventional direct resin filling. Methods: Finite element software is used to simulate axial and lateral loads, and analyze the stress value and distribution of intact teeth and different restoration models. Results: The equivalent stress magnitude under lateral loading was significantly higher when compared to that under axial loading. Additionally, the stress levels observed in all the restoration groups exceeded those found in intact teeth under lateral load. It was observed that under the two loading conditions, the endocrown group exhibited the lowest maximum EQV stress. The highest EQV stress peak values were observed in the resin group, affecting the residual dental tissue. The stress distribution varied across each model section. The endocrown group effectively dispersed stress to the dental tissue under both loads. Significant concentrations of stress were observed in the dental tissue surrounding the resin group filling. Conclusions: After root canal treatment, the lateral force should be controlled, the pulp cavity can more evenly transfer the bite force, and a risk of long-term resin filling or dental fracture.