Northeastern University, Department of Mechanical Engineering, Boston, Massachusetts 02115, USA.
Int J Oral Maxillofac Implants. 2012 Jul-Aug;27(4):e39-48.
The aim of this study was to investigate peri-implant bone remodeling as a response to biomechanical factors, including implant size and contour, magnitude of occlusal load, and properties of osteogenic bone grafts through the use of a computational algorithm.
A bone-remodeling algorithm was incorporated into the finite element method, where bone remodeling takes place as a result of the biomechanical alteration caused by dental implant placement and continues until the difference between the homeostatic state and the altered state is minimized. The site-specific homeostatic state was based on a model consisting of a natural tooth. Three long (11-mm) implants and two short (5-mm) implants were investigated. A three-dimensional segment of the mandible was constructed from a computed tomographic image of the premolar region, and an extraction socket was filled with bone graft.
Generally, the extent of bone loss in the cortical region was greater and denser bone developed at both the implant crest and apex with increased occlusal loads. The areas between implant threads were prone to bone resorption. Bone graft materials that were relatively stiff and that had high equilibrium stimulus values appeared to cause increased bone loss.
Short implants are better for conserving the mechanotransductive signaling environment of the natural tooth than long implants. Also, short implants are predicted to lead to less interfacial bone loss at high loads over the long term, while long implants are associated with a more consistent level of bone loss for different amounts of loading. It is also predicted that in the long term, bone grafts with relatively low elastic modulus lead to lower levels of interfacial bone loss.
本研究旨在通过计算算法，研究种植体大小和轮廓、咬合负荷大小以及成骨骨移植物特性等生物力学因素对种植体周围骨重塑的影响。
将骨重塑算法纳入有限元法中，在该方法中，由于种植体放置引起的生物力学改变，骨重塑发生，并且持续进行，直到平衡状态和改变状态之间的差异最小化。特定部位的平衡状态基于由天然牙组成的模型。研究了三个长（11mm）种植体和两个短（5mm）种植体。从磨牙区的计算机断层扫描图像构建下颌骨的三维片段，并在拔牙窝中填充骨移植物。
通常，皮质区的骨丢失程度更大，随着咬合负荷的增加，在种植体嵴和根尖处形成更密集的骨。种植体螺纹之间的区域容易发生骨吸收。相对较硬且具有较高平衡刺激值的骨移植物材料似乎会导致骨丢失增加。
与长种植体相比，短种植体更有利于保持天然牙的机械转导信号环境。此外，长期来看，短种植体在高负荷下预计会导致界面骨丢失减少，而长种植体与不同负荷量的界面骨丢失水平更一致。还预测，在长期内，具有相对较低弹性模量的骨移植物会导致较低水平的界面骨丢失。
