Orthodontic examination on correspondence between change in occlusion and periodontal mechanoreceptors-by means of biomechanical, physiological, and immunohistological approaches-

本研究的目的是通过生物力学、生理学和免疫组织学的方法来阐明正畸治疗前后牙周机械感受器的动态变化。我们改进了咬合力传感器（传感器核心为压敏橡胶），用于测量整个牙列瞬间变化的咬合力。也就是说，我们设计了这种小尺寸的传感器，可以一颗一颗地测量牙齿。我们测量了每颗牙齿在工作时的咬合力。采用光纤传感器间接三维测量上颌中切牙的微小位移。根据施加外力的不同位置，位移模式不同，可以观察到齿的旋转中心发生变化的现象。使用直接接触式微小位移仪测量上颌第一磨牙在咬合时的位移量，结果表明，上颌第一磨牙与下颌第一磨牙的接触方式不同，导致牙的位移量也不同。大鼠牙周机械感受器的主要神经支配是A δ纤维。与快速适应型和缓慢适应型混合的门牙相比，磨牙只有快速适应型。此外，提取拮抗剂后大鼠牙周机械感受器的适应特性变化，可以观察到机械刺激下阈值的变化，以及反应模式比例的变化。此外，在小鼠中，咀嚼所必需的神经传递物质随着生长而改变。免疫组织学方法在出生3周龄小鼠下门牙上放置诱导前牙合装置2、4、6、8周后，在取出诱导前牙合装置2、4、6、8周后，采用PGP- 9.5免疫组织学方法观察Ruffini神经末梢的分布及形态变化。上颌前切牙牙周膜腭侧的鲁菲尼神经末梢与诱导前交叉咬合时一样发生变性和变弱。然而，在移除矫治器后前牙合改善的情况下，Ruffini神经末梢再生。因此，我们证实了咬合变化与牙周机械感受器之间的对应关系。少

The purpose of this research is to clarify the dynamic change of periodontal mechanoreceptors before and after orthodontic treatment by means of biomechanical, physiological and immunohistological approaches.1. Biomechanical approachWe improved occlusal force sensor (the core of the sensor was a pressure sensitive rubber) which was designed to measure the momentarily changing occlusal force of the whole dentition. That is to say, we devised this sensor of small size to measure tooth one by one. And we measured the occlusal force onto each tooth when functioning.The minute displacement of the maxillary central incisor was measured three dimensionally indirectly with optic fiber sensor. According to different spots where external force Was applied, the pattern of displacement varied, and the phenomenon that center of rotation of the tooth changed could be observed. Also, we measured the displacement of the maxillary first molar when clenching with direct-contact minute displacement devic … More e. It indicated that different contact pattern between the upper and lower first molars resulted in varied tooth displacement pattern.2. Physiological approachThe main innervation nerves of periodontal mechanoreceptors of rats are A delta fibers. In contrast with incisors, of mixed fast-adapted and slowly-adapted types, only fast-adapted types can be found in molars. Moreover, as for the change in adaptive characteristics of periodontal mechanoreceptors of rats after antagonists were extracted, change of threshold in response to mechanical stimulation could be seen, and the change of proportion of reaction patterns could also be observed. Furthermore, in mice, the nerve transmission substances necessary for mastication changed with growth.3. Immunohistological approach2,4,6 and 8 weeks after we set a device onto the lower incisors of mice of 3 weeks old after birth to induce anterior crossbite, and another 2,4,6 and & weeks after the device used for inducing anterior crossbite was removed, we utilized immunohistological method to observe the distribution and morphological change of Ruffini nerve endings by PGP- 9.5. As with anterior crossbite was induced, the Ruffini nerve endings located at the palatal sides of the periodontal membranes of the anterior maxillary incisors degenerated and lessened. However, in the case that anterior crossbite ameliorated after the appliance was removed, Ruffini nerve endings regenerated. Thereby, we confirmed the correspondence between change of occlusion and periodontal mechanoreceptors. Less