Analysis of jaw bone periosteum for prognosis of dental implant outcome

种植牙治疗的成功至少依赖于骨膜细胞分泌的皮质骨基质。为了探讨下颌骨皮质基质的情况，本研究采用两种不同下颌骨皮质宽度的小鼠模型进行了胶原的生化分析，并在人体身体上比较了下颌骨和四肢的皮质骨基质。老年性骨质疏松症小鼠(SAMP6)的下颌骨皮质与其对照组(SAMR1)相比，在组织学上不仅皮质厚度较小，而且基质堆积较少。此外，SAMP6的胶原含量较低，赖氨酸羟化程度较高，与胶原纤维直径较小相吻合。此外，SAMP6中还观察到少量的胶原分子间交联物。这些结果表明，SAMP6的下颌骨皮质骨体积较小，其最丰富的基质蛋白-胶原蛋白的数量和质量都较少。在人体身体中，下颌骨皮质骨的矿物质和胶原含量较高，而胶原蛋白的赖氨酸羟化程度较低，提示下颌骨的骨基质质量比四肢好。事实上，这三个指数的值因个人而异。因此，下颌骨的皮质骨在基质成分上表现出个体间的差异。本研究结果提示，骨膜细胞的最终产物--皮质骨基质，主要是胶原蛋白的分析，可以揭示骨基质的各种性质，并可用于预测将来种植牙的效果。

Success of dental implant treatment at least depends on cortical bone matrix secreted by periosteal cells. To explore the aspect of cortical matrix of mandibular bone, this study performed biochemical analysis of collagen using two mouse models with different cortical width of mandibular bone, and compared cortical bone matrix of the mandible with that of the limbs in human cadavers. The mandibular cortical bone of senile osteoporotic mice (SAMP6), with comparison of their control mice (SAMR1), showed not only smaller cortical thickness but also less packed matrix histologically. Furthermore, SAMP6 exhibited lower content of collagen and higher extent of lysine hydroxylation of collagen, coincided with smaller diameter of collagen fibrils. As well, smaller amount of intermolecular cross-links of collagen was seen in SAMP6. These findings indicate that the mandibular cortical bone of SAMP6 with smaller bone volume of the cortex possesses less quantity and quality of the most abundant matrix protein, collagen. In human cadavers, the mandibular cortical bones showed higher contents of mineral and collagen but lower extent of lysine hydroxylation of collagen than the humeral and femoral cortical bones, suggesting better quality of bone matrix in the mandible compared with the limbs. In fact, values of the three indices varied among individuals. Thus, the cortical bone of the mandible exhibits inter-individual variation in matrix composition. The results of this study suggest that the analysis of cortical bone matrix, primarily collagen, which is the final product by periosteal cells, can disclose the various property of bone matrix and could be available for prognosis of dental implant outcome in future.