PhD candidate, Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
J Prosthet Dent. 2010 Jan;103(1):6-12. doi: 10.1016/S0022-3913(09)60206-7.
Previous research into the strength of endodontically treated or vital teeth restored with inlays or onlays has not determined which restoration method and material provide the most favorable stress distribution upon loading.
The purpose of this study was to calculate the von Mises stresses in a mandibular first molar using a 3-dimensional (3-D) finite element model. Models compared endodontically treated and vital teeth, a variety of restorative materials, and the use of either inlays or onlays to restore teeth.
Four 3-D models of mandibular first molars were created: (1) the IV group (inlay restored, vital pulp); (2) the OV group (onlay restored, vital pulp); (3) the IE group (inlay restored, endodontically treated); and (4) the OE group (onlay restored, endodontically treated). In each group, 3 types of restorative material were tested: (1) composite resin, (2) ceramic, and (3) gold alloy. The materials had elastic moduli of 19 GPa, 65 GPa, and 96.6 GPa, respectively. Each model was subjected to a force of 45 N directed to the occlusal surface, applied either vertically or laterally (45 degrees obliquely). The stresses occurring in dentin tissue were calculated. The stress distribution patterns and the maximum von Mises stresses were calculated and compared.
The different restorative materials exhibited similar stress distribution patterns under identical loading conditions. In each group, the gold-restored tooth exhibited the highest von Mises stress, followed by ceramic and composite resin. The maximum von Mises stress in dentin was found in the IE group (16.73 MPa), which was 5 times higher than the highest value found in the OV group (2.96 MPa). The highest stresses, which occurred at the floor of the preparation and the cervical region in dentin, were in the IE group. The stress concentration area in the IE group was also larger.
The results indicate that endodontic treatment caused higher stress concentration in dentin compared with vital teeth, but that proper restoration can minimize internal stresses. In the models, the von Mises stress values increased with the increasing elastic modulus of the restorative material. Composite resin onlays showed the best performance overall in minimizing internal stresses. As internal stresses are indicated as a prime failure mechanism of the restoration, composite resin onlays are expected to better restore structural integrity.
以前关于用嵌体或高嵌体修复的根管治疗或活髓牙的强度的研究，并未确定哪种修复方法和材料在加载时能提供最有利的应力分布。
本研究旨在通过三维（3-D）有限元模型计算下颌第一磨牙的 von Mises 应力。模型比较了根管治疗和活髓牙、各种修复材料以及嵌体或高嵌体修复牙齿的情况。
创建了四个下颌第一磨牙的 3-D 模型：（1）IV 组（嵌体修复，活髓）；（2）OV 组（高嵌体修复，活髓）；（3）IE 组（嵌体修复，根管治疗）；（4）OE 组（高嵌体修复，根管治疗）。在每组中，测试了 3 种修复材料：（1）复合树脂，（2）陶瓷，（3）金合金。这些材料的弹性模量分别为 19 GPa、65 GPa 和 96.6 GPa。每个模型都受到 45 N 的力，方向指向咬合面，施加垂直或侧向（45 度斜向）。计算了牙本质组织中的应力。计算并比较了发生的应力分布模式和最大 von Mises 应力。
不同的修复材料在相同的加载条件下表现出相似的应力分布模式。在每组中，金修复的牙齿表现出最高的 von Mises 应力，其次是陶瓷和复合树脂。在 IE 组中，牙本质中发现的最大 von Mises 应力最高（16.73 MPa），是 OV 组（2.96 MPa）最高值的 5 倍。在 IE 组中，在预备体的底部和牙本质的颈部区域发现了最高的应力，IE 组的应力集中区域也更大。
结果表明，与活髓牙相比，根管治疗会导致牙本质中的更高的应力集中，但适当的修复可以最小化内部应力。在模型中，随着修复材料弹性模量的增加，von Mises 应力值也增加。复合树脂嵌体总体上表现出最小化内部应力的最佳性能。由于内部应力被认为是修复体失效的主要机制，因此预计复合树脂嵌体能够更好地恢复结构完整性。
Zotero 插件