Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
J Craniomaxillofac Surg. 2011 Jul;39(5):343-50. doi: 10.1016/j.jcms.2010.07.006. Epub 2010 Aug 30.
A 3D finite element model of in vitro intact and implanted mandibles with different temporomandibular joints (TMJ) was analyzed. Three TMJ implant geometries were assessed. The displacements, stress and strain fields on the condyle were obtained for both simulated cases. Strains were also assessed near the screws that fixate the implant to the mandible. The geometry of the mandible was obtained through 3D digitalization of a synthetic model. The TMJ implants studied were modelled considering a commercial implant which was also used to create semi-anatomic and anatomic implants that were analyzed and to assess the influence of the geometry. Numerical finite element models were built and the implants were positioned by an experienced orofacial surgeon. All implants were fixed by four screws which were placed in the same position on the mandible. The boundary conditions were simulated considering the support on the incisive tooth, the loads of the five most important muscular forces and a 5mm mouth aperture. This study indicates that the deformation on the intact mandible was similar when an anatomic implant was considered in the implanted mandible. However, the anatomic geometry presented some problems concerning the implant integrity due to geometric variations. The geometry of TMJ implant also played a role relatively to the screws structural integration and bone fixation. The geometry of TMJ implant defines the necessary number of screws and position in the mandible fixation.
分析了体外完整和植入下颌骨的三维有限元模型，这些下颌骨具有不同的颞下颌关节（TMJ）。评估了三种 TMJ 植入物几何形状。获得了模拟情况下髁突的位移、应力和应变场。还评估了固定植入物到下颌骨的螺钉附近的应变。下颌骨的几何形状是通过合成模型的三维数字化获得的。研究的 TMJ 植入物考虑了一种商业植入物进行建模，该植入物也用于创建半解剖和解剖植入物，以评估几何形状的影响。建立了数值有限元模型，并由经验丰富的口面外科医生定位植入物。所有植入物均通过四颗螺钉固定，这些螺钉放置在下颌骨的相同位置。边界条件考虑了切牙的支撑、五个最重要的肌肉力的载荷和 5mm 的张口来模拟。本研究表明，在植入的下颌骨中考虑解剖植入物时，完整下颌骨的变形相似。然而，由于几何变化，解剖几何形状对接合器完整性存在一些问题。TMJ 植入物的几何形状也与螺钉的结构完整性和骨固定有关。TMJ 植入物的几何形状定义了下颌骨固定所需的螺钉数量和位置。
