Evaluation of Stress Distribution in Endodontically Weakened Teeth Restored with Different Crown Materials: 3D-FEA Analysis

Abstract This study evaluated the stress distribution in endodontically treated teeth, weakened (W) or not weakened (NW), restored with different materials of prosthetic crown using 3D-FEA. Models of a maxillary canine were constructed based on micro-CT images and divided into the groups: G1 (control) - sound tooth; G2 to G7 - endodontically treated teeth restored with glass fiber post (GFP); which G2 to G4 simulated NW root and G5 to G7 simulated W root. For crown material the teeth were restored with: G2 and G5: metallic coping and ceramic veneering, G3 and G6: zirconia coping and ceramic veneering, G4 and G7: alumina coping and ceramic veneering. Load of 180 N was applied at the incisal third of lingual surface at 45º. Models were supported by the periodontal ligament (x=y=z=0). The von Mises stress (VMS) values were calculated. The W teeth presented higher VMS at coping when compared to NW teeth and group G1 showed lower VMS value. For crown material, for both W or NW teeth, increasing VMS was found at metallic, zirconia and alumina coping, respectively. Metallic coping showed a better performance despite its unfavorable esthetics, suggesting as an appropriate material for prosthetic restoration of endodontically treated teeth.

摘要 本研究采用三维有限元分析（3D-FEA），评估了经牙髓治疗后、存在牙体缺损削弱（W组）与未削弱（NW组）的上颌尖牙，采用不同修复冠材料时的应力分布情况。研究基于显微CT（micro-CT）图像构建上颌尖牙模型，并分为以下组别：G1（对照组）为完整天然牙；G2至G7为经牙髓治疗后采用玻璃纤维桩（GFP）修复的患牙，其中G2至G4模拟未削弱牙根，G5至G7模拟缺损削弱牙根。按冠修复材料进一步分组：G2与G5采用金属基底冠+陶瓷饰面；G3与G6采用氧化锆基底冠+陶瓷饰面；G4与G7采用氧化铝基底冠+陶瓷饰面。于舌面切端1/3处施加45°方向的180N载荷，模型以牙周膜为支撑边界（x、y、z方向均约束为0）。研究计算了冯·米塞斯应力（VMS）值。结果显示，缺损削弱组患牙的基底冠冯·米塞斯应力值高于未削弱组，且G1组的应力值最低。无论牙根是否缺损削弱，不同冠修复材料的基底冠冯·米塞斯应力均依次为金属、氧化锆、氧化铝递增。尽管金属基底冠的美观性欠佳，但其表现出更优的力学性能，提示其可作为牙髓治疗后患牙修复的适宜材料。