Studies on the biological responses to mechanical stress on jaw bone and periodontium, and their clinical applications.

为了研究机械应力对颌骨和牙周组织的生物学效应，本研究旨在通过对牙齿施加正畸力，扩大牙周膜间隙，以便于拔牙，减少牙周膜的损伤。实验组在上颌第二磨牙施加正畸力，7 d后再植或拔除上颌第二磨牙，再植14 d后处死动物，观察拔除牙牙周膜附着情况和牙根面暴露情况。正畸力作用7 d后，牙周膜间隙增大，牙槽窝宽度增大，牙周膜在离体牙牙根面附着丰富。而在对照组中，未预先施加正畸力的牙根在修复后14天可检测到明显的牙根吸收，这可能与牙周膜的破坏相一致。 ...更多信息 antation。这些结果表明，对供牙预先施加正畸力可以增加PDL宽度，减轻拔除难度，从而抑制再植后牙根的吸收。本实验观察了咬合负荷对大鼠牙再植后牙槽骨改建及血管活性肠肽（VIP）和降钙素基因相关肽（CGRP）免疫反应（IR）纤维分布的影响。在第5天，咬合负荷诱导破骨细胞数量和成骨细胞表面与非咬合组相比显着增加。VIP-IR纤维在成骨细胞层旁可见，与非闭塞组相比，闭塞组第5天VIP-IR纤维的分布明显增强。CGRP在牙周膜和牙槽骨中呈阳性反应，但在根分叉处未见阳性反应。这些结果表明，大鼠牙再植后，咬合负荷诱导破骨细胞和成骨细胞的形成增加，VIP可能在成骨细胞中发挥功能性作用。少

In order to investigate the biological responses to mechanical stress on jaw bone and periodontium, we aimed to apply the orthodontic force to the teeth in order to enlarge the space of periodontal ligaments (PDL), which may ease extraction and minimize the damage of PDL before transplantation. The orthodontic force was applied to the right upper molars for the experimental group, and after 7days, upper second molars were replanted or extracted, where replanted animals were then sacrificed after 14 days and those extracted teeth were examined for the attached PDL and exposed root surface. The application of orthodontic force for 7 days increased the PDL space and also the width of the alveolar socket, which resulted in the rich attached PDL to the root surface of the extracted teeth. And enhanced root resorption that may have been coincided with the disruption of the PDL was detected in the root of the control group without pre-application of orthodontic force at the 14 days after repl … More antation. These results suggested that the pre-application of orthodontic force to the donor teeth increased the PDL width and ease the extraction, which may inhibit the root resorption after replantation. The influences of occlusal loading on the alveolar bone remodeling and the distribution of vasoactive intestinal peptide (VIP)- and calcitonin generelated peptide (CGRP)-immunoreactive (IR) fibers were investigated after tooth replantation in rats. At day 5, occlusal loading induced a significant increase in osteoclast number and osteoblast surface compared to those in the non-occluded group. VIP-IR fibers were observed beside osteoblastic layers and their distribution was significantly enhanced at day 5 in the occluded group, compared to the non-occluded group. Although there was immunoreactivity for CGRP in the periodontal ligament and alveolar bone apically, CGRP-IR fibers were not detected above the furcation. These results suggest that, after tooth replantation in rats, occlusal loading induced an increase in osteoclast and osteoblast formation, and that VIP might play a functional role in osteoblasts. Less