Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA.
Sci Rep. 2020 Mar 9;10(1):4335. doi: 10.1038/s41598-020-60735-7.
Long-term bone healing/adaptation after a dental implant treatment starts with diffusion of mesenchymal stem cells to the wounded region and their subsequent differentiation. The healing phase is followed by the bone-remodeling phase. In this work, a mechano-regulatory cellular differentiation model was used to simulate tissue healing around an immediately loaded dental implant. All tissue types were modeled as poroelastic in the healing phase. Material properties of the healing region were updated after each loading cycle for 30 cycles (days). The tissue distribution in the healed state was then used as the initial condition for the remodeling phase during which regions healed into bone adapt their apparent density with respect to a homeostatic remodeling stimulus. The short- (bone healing) and long-term (bone remodeling) effects of initial implant micromotion during the healing phase were studied. Development of soft tissue was observed both in the coronal region due to high fluid velocity, and on the vertical sides of the healing-gap due to high shear stress. In cases with small implant micromotion, tissue between the implant threads differentiated into bone during the healing phase but resorbed during remodeling. In cases with large implant micromotion, higher percentage of the healing region differentiated into soft tissue resulting in smaller volume of bone tissue available for remodeling. However, the remaining bone region developed higher density bone tissue. It was concluded that an optimal range of initial implant micromotion could be designed for a specific patient in order to achieve the desired long-term functional properties.
长期的骨愈合/适应在牙种植体治疗后开始于间充质干细胞扩散到受伤区域及其随后的分化。愈合阶段之后是骨重塑阶段。在这项工作中，使用机械调节细胞分化模型来模拟立即加载牙种植体周围的组织愈合。在愈合阶段，所有组织类型都被建模为多孔弹性体。在 30 个加载周期（天）中的每个加载周期后更新愈合区域的材料性能。然后将愈合状态下的组织分布用作重塑阶段的初始条件，在此阶段，愈合区域的骨适应其相对于平衡重塑刺激的表观密度。研究了愈合阶段初始植入体微动对短期（骨愈合）和长期（骨重塑）的影响。在冠状区域由于高流速，以及在愈合间隙的垂直侧由于高剪切应力，观察到软组织的发育。在植入体微动较小的情况下，植入体螺纹之间的组织在愈合阶段分化为骨，但在重塑阶段吸收。在植入体微动较大的情况下，更多的愈合区域分化为软组织，导致可用于重塑的骨组织体积减小。然而，剩余的骨区域发育出更高密度的骨组织。结论是，可以为特定患者设计初始植入体微动的最佳范围，以达到预期的长期功能特性。
