DEVELOPMENT OF ORTHODONTIC BONE RESPONSE MODELS

骨的形成和吸收与机械负荷或 几个世纪以来。目前关注的问题包括：绝经后骨质疏松症， 骨骼发育，骨科和牙科植入物的预后， 医源性正畸牙根吸收和长期失重。 对非骨细胞的机械影响现在也接近尾声 仔细检查。一个常见的未知数是机械振动的传导机制。 迫使细胞做出反应。一种研究方法是使用应力分析 用于对加载的骨骼进行建模的工具(有限元方法，FEM)。A组件 (应力、应变能...)计算出的机械环境的 然后与观察到的骨丢失和/或获得相关联 骨头。这种攻击被用于正畸的二维分析。 大鼠磨牙牙槽骨的骨反应。拟议中的项目意在 通过将重点放在 PDL细胞对正畸治疗的初始反应。离开和优势 相对于矫形外科方法，独特的正畸模型的特点是： (1)正畸精密施加的实验力较大。 可控和创伤性的力量应用于长骨，(2) 同样的系统(牙齿-牙槽骨)会暴露在非常不同的环境中 加载条件(牙齿倾斜、侵入、挤压、侧向 平移或轴向旋转)，以及(3)研究的重点包括 牙周膜，骨形成的软组织储存库 前体细胞，而不仅仅是硬组织本身。这种方法， 结合组织学和工程学分析，产生了新的 概念。我们确定骨形成可能与 PDL软组织内的机械环境，而 骨吸收可能与骨骼本身所处的环境有关。 可归因于解剖复杂性的障碍(五根)和 通过拟议的开发，可以克服大鼠磨牙的小尺寸 基于更大的狗牙的新的(正畸和工程)模型。 因此，这个跨学科项目的目标是：(1)建立 一种更大、更简单(相对于大鼠磨牙)的犬牙模型 正畸运动，(2)计算相应的机械力 环境三维有限元应力分析，以及(3) 统计调查组件之间的关系(张力， 剪切力等)的力学环境和新的实验 结果。为此，狗的下颌第二前磨牙将倾斜 最远的24小时。连接到颊上粘合托槽的弹性件 第二和第三前磨牙的舌面将提供 武力。PDL细胞合成DNA的分布 正畸将通过BrdU标签进行确定。我们期待着 这些标记细胞的分布模式与 有限元计算了某些机械部件的分布。此，的 当然，这将是关于机械刺激的有价值的信息 可能与细胞反应有关。未来的研究将需要寻找 在其他(轴向旋转、平移、插入、挤出)齿上 动静。这之后应该对长骨进行类似的研究。 行为，包括对机械环境的考虑 在骨膜内。

Bone formation and resorption have been linked to mechanical loads or centuries. Current concerns include: post-menopausal osteoporosis, skeletal development, prognosis for orthopedic and dental implants, iatrogenic orthodontic root resorption, and long-term weightlessness. Mechanical influences on non-bone cells are now also under close scrutiny. A common unknown is the transduction mechanism of mechanical forces into cell responses. One study approach uses a stress analysis tool (Finite Element Method, FEM) to model a loaded bone. A component (stress, strain energy ...) of the calculated mechanical environment within the bone is then associated with the observed loss and/or gain of bone. This attack was used in a two-dimensional analysis of orthodontic bone response in rat molar alveolus. The proposed project is intended to expand, refine, and further validate that model by focusing on the initial PDL cell response to orthodontics. The departures and advantages of the unique orthodontic model relative to orthopedic approaches are: (1) the experimental forces, applied with orthodontic precision, are more controllable and a traumatic than forces applied to long-bones, (2) the same system (tooth-alveolar bone) can he exposed to very different loading conditions (tooth tipping, intrusion, extrusion, lateral translation, or axial rotation), and (3) the focus of the study includes the periodontal ligament, the soft tissue reservoir of bone forming precursor cells, not only the hard tissues themselves. This approach, combining histologic and engineering analyses, has yielded novel concepts. We determined that bone formation may be linked to the mechanical environment within the soft tissues of the PDL, while resorption may be associated with the environment within the bone itself. The obstacles attributable to the anatomic complexity (five roots) and small size of the rat molar can be overcome with the proposed development of new (orthodontic and engineering) models based on larger dog teeth. Thus, the aims of this interdisciplinary project are to: (1) establish a larger and simpler (relative to rat molar) dog tooth model for orthodontic movement, (2) calculate the corresponding mechanical environment with three-dimensional FEM stress analysis, and (3) statistically investigate the relationship between components (tension, shear, etc.) of the mechanical environment and the new experimental results. To do so, dog mandibular second premolars will be tipped distally for 24 hours. Elastics attached to bonded brackets on the buccal and lingual surfaces of the second and third premolars will provide the force. The distribution of PDL cells synthesizing DNA as a result of orthodontics will be determined with BrdU labels. We expect the distribution pattern of these labelled cells to be correlated with the FEM calculated distributions of certain mechanical components. This, of course, would be valuable information about the mechanical stimulus that may be associated with cell response. Future research would need to look at other (axial rotation, translation, intrusion, extrusion) tooth movements. That should be followed by similar studies of long-bone behavior, including the consideration of the mechanical environment within the periosteum.