Department of Mechanical Engineering, Chang Gung University, Tao-yuan, Taiwan.
J Periodontol. 2010 Jan;81(1):121-30. doi: 10.1902/jop.2009.090331.
This study investigated the biomechanical interactions in tooth-implant-supported fixed partial dentures (FPDs) with variations in periodontal support, implant system, number of splinted teeth, and load type using the non-linear finite element (FE) approach.
The section contours of the alveolar bone, abutment teeth, and prosthesis were acquired using computed tomography (CT) and micro-CT to construct the FE models with normal periodontal support (NPS) and compromised periodontal support (CPS) containing one- and two-piece implants splinted to the first and second premolars. Realistic interface conditions within the implant system were simulated using frictional contact elements. The main effects for each level of investigated factors in terms of stress values and dissimilar mobility of natural teeth and the implant were computed for all models.
Analytic results indicated that the load condition was the predominant factor affecting stress developed in the implant, bone, and prosthesis. Additionally, the oblique occlusal forces increased the stress values relative to that of axial analogs. A splinted system with a two-piece implant increased stress on the bone and decreased stress on the prosthesis compared to that of the one-piece implant. The splinted system with a CPS only slightly increased implant stress on the bone compared to that of the splint system with NPS. Splinting an additional tooth did not significantly impact stress values for the tooth-implant-supported FPD.
A one-piece structure implant may be better than that of a two-piece structure implant in decreasing bone stress when a natural tooth is planned to connect with an implant. The factors of periodontal support and number of splinted teeth only slightly influenced stress in tooth-implant-supported FPDs.
本研究采用非线性有限元（FE）方法，研究了牙周支持、种植体系统、桥接牙数量和载荷类型变化时，牙-种植体支持的固定局部义齿（FPD）中的生物力学相互作用。
使用计算机断层扫描（CT）和微 CT 获得牙槽骨、基牙和修复体的剖面轮廓，构建具有正常牙周支持（NPS）和受影响牙周支持（CPS）的 FE 模型，其中包含单和双部件植入物桥接到第一和第二前磨牙。使用摩擦接触元件模拟种植体系统内的真实界面条件。对于所有模型，计算了各研究因素各水平的主要效应，以评估天然牙和种植体的应力值和不相似移动性。
分析结果表明，载荷条件是影响种植体、骨和修复体中产生的应力的主要因素。此外，斜向咬合力相对于轴向模拟增加了应力值。与单部件植入物相比，双部件植入物的桥接系统增加了骨上的应力，减少了修复体上的应力。与 NPS 桥接系统相比，CPS 桥接系统仅略微增加了骨上的植入物应力。桥接额外的牙齿不会显著影响牙-种植体支持的 FPD 的应力值。
当计划将天然牙与种植体连接时，与双部件结构植入物相比，单部件结构植入物可能更有利于减少骨上的应力。牙周支持和桥接牙数量等因素仅对牙-种植体支持的 FPD 的应力产生轻微影响。
