Wang Z, Feng J, Chen J H, Zhao K
Department of Stomatology, Xinyang Central Hospital, Xinyang 464000, China.
Department of Prosthodontics, Hospital of Stomatology, Sun Yat-sen University, Guangzhou 510030, China.
Zhonghua Yi Xue Za Zhi. 2022 Sep 6;102(33):2624-2629. doi: 10.3760/cma.j.cn112137-20220319-00584.
To improve the mechanical properties of full-crown restorations and illuminate the optimal elastic modulus distribution through bionic optimization design and finite element analysis (FEA). Seven 3D models of mandibular first premolars with different full-crown restorations were constructed: (A) zirconia monolithic crown, (B) lithium disilicate monolithic crown, (C) zirconia bilayer crown, (D) lithium disilicate bilayer crown, (E) 8-layer crown referred to the elastic modulus distribution of human enamel, (F) and (G) were 8-layer crowns with elastic modulus distribution calculated by a genetic algorithm (GA) to minimize the tensile stresses in the crown and the shear stresses at the cementing line, respectively. Results in the crowns and cementing lines were obtained with maximum principal stress after applying a static load of 600 N. The principal tensile stresses in the full-crown restorations were mainly concentrated in the cervical margins and the crown-cementing interface. Among them, G exhibited a peak tensile stress of 25.79 MPa, which decreased to 17.72 MPa in E and 16.25 MPa in F; The principal shear stresses in cementing lines were concentrated along the margins and low on the axial wall. The peak shear stress of the cementing line of E and F was 11.81 MPa and 11.79 MPa, respectively. While G was found to has the lowest peak shear stress of 6.14 MPa. The elastic modulus distribution optimized by GA to reduce the peak shear stress of the cementing line can better improve the mechanical properties of the full-crown restoration.
为了改善全冠修复体的力学性能，并通过仿生优化设计和有限元分析（FEA）阐明最佳弹性模量分布。构建了七种具有不同全冠修复体的下颌第一前磨牙的三维模型：（A）氧化锆整体冠，（B）二硅酸锂整体冠，（C）氧化锆双层冠，（D）二硅酸锂双层冠，（E）参照人牙釉质弹性模量分布的8层冠，（F）和（G）是分别通过遗传算法（GA）计算弹性模量分布以最小化冠内拉应力和粘结线处剪应力的8层冠。在施加600 N静载荷后，获得了冠部和粘结线处的最大主应力结果。全冠修复体中的主拉应力主要集中在颈部边缘和冠 - 粘结界面。其中，G的拉应力峰值为25.79 MPa，在E中降至17.72 MPa，在F中降至16.25 MPa；粘结线中的主剪应力沿边缘集中，在轴壁上较低。E和F粘结线的剪应力峰值分别为11.81 MPa和11.79 MPa。而G的剪应力峰值最低，为6.14 MPa。通过GA优化弹性模量分布以降低粘结线的剪应力峰值可以更好地改善全冠修复体的力学性能。
