An Jingtao, Li Ying, Liu Zhongshuang, Wang Rui, Zhang Bin
Department of Orthodontics, School of Stomatology, Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China.
Institute of Hard Tissue Development and Regeneration, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
Exp Ther Med. 2017 May;13(5):1793-1798. doi: 10.3892/etm.2017.4186. Epub 2017 Mar 6.
The dynamic changes of the microstructure of alveolar bone during orthodontic tooth movement in rats was explored by employing micro-computed tomography (micro-CT) system and to provide theoretical reference for clinical orthodontic treatment. Ten rats were selected randomly as control among 70 adult female Wistar rats, and the other 60 rats were divided into 25-g and 75-g groups of equal number. Orthodontic appliance with force of 25 g and 75 g was installed to perform the molar mesial movement. Microstructural parameters for trabecular bone mesial to the distobuccal root were evaluated at different time points using micro-CT system. Moreover, distance for mesial movement of the molar were measured. Microstructural parameters for trabecular bone of two groups showed no significant changes from day 0 to day 3 (P>0.05); from day 3 to day 7, bone mineral density (BMD), bone volume/total volume (BV/TV) and trabecular thickness (Tb.Th) decreased significantly (P<0.05), whereas trabecular separation (Tb.Sp) and structure model index (SMI) increased significantly (P<0.05); from day 7 to day 14, in 25-g group, BMD, BV/TV and Tb.Th increased significantly (P<0.05), while Tb.Sp and SMI decreased significantly (P<0.05). Correspondingly, in 75-g group, changes of parameters did not carry any statistical significance (P>0.05). Furthermore, the 75-g group showed larger distance than 25-g group only at day 14 (P<0.05). In conclusion, in order to maintain the health of periodontal tissues, adequate time for repair and recovery is needed to ensure reasonable remolding of alveolar bone and healthy movement of the orthodontic tooth.
采用微计算机断层扫描（micro-CT）系统探索大鼠正畸牙齿移动过程中牙槽骨微观结构的动态变化，为临床正畸治疗提供理论参考。在70只成年雌性Wistar大鼠中随机选取10只作为对照组，其余60只大鼠等分为25 g组和75 g组。安装施加25 g和75 g力的正畸矫治器以使磨牙向近中移动。使用micro-CT系统在不同时间点评估远中颊根近中侧松质骨的微观结构参数。此外，测量磨牙近中移动的距离。两组松质骨的微观结构参数在第0天至第3天无显著变化（P>0.05）；第3天至第7天，骨密度（BMD）、骨体积/总体积（BV/TV）和骨小梁厚度（Tb.Th）显著降低（P<0.05），而骨小梁间距（Tb.Sp）和结构模型指数（SMI）显著增加（P<0.05）；第7天至第14天，25 g组中，BMD、BV/TV和Tb.Th显著增加（P<0.05），而Tb.Sp和SMI显著降低（P<0.05）。相应地，在75 g组中，参数变化无统计学意义（P>0.05）。此外，仅在第14天，75 g组显示出比25 g组更大的移动距离（P<0.05）。总之，为了维持牙周组织的健康，需要足够的修复和恢复时间，以确保牙槽骨的合理重塑和正畸牙齿的健康移动。
