Brudvik P, Rygh P
Department of Orthodontics and Facial Orthopedics, Faculty of Dentistry, University of Bergen, Norway.
Eur J Orthod. 1995 Jun;17(3):189-98. doi: 10.1093/ejo/17.3.189.
It has previously been shown by light (LM) and scanning electron microscopy (SEM), that after force is terminated, repair of the orthodontic root resorption lacunae occur by deposition of new cementum. The ultrastructural details of the process are not well established. Since it has been hypothesized that a new barrier to protect the root surface is formed during the reparative phase, new information on this aspect of orthodontic root resorption may be valuable. The aim of the present investigation was, by using transmission electron microscopy (TEM), to study in more detail the repair of orthodontic root resorption lacunae and the re-establishment of the adjacent periodontal membrane (PM). Three experimental tooth movement groups of rats (age 40-45 days) were used. The maxillary first molar was moved mesially by a closed coil spring for 10, 14, and 21 days. The results indicate that transition of active root resorption into a process of repair which occurs even in the presence of a light force, is associated with invasion of fibroblast-like cells from the circumference into the active root resorption site. After 10 days, formation of new tooth supporting structures was seen in the periphery of the resorption lacunae, while active resorption by multinucleated odontoclast-like cells (OD) took place in the central parts. In the later phases, after termination of force, the repair process is similar to the early cementogenesis occurring during tooth development. New mineralized cementum was observed on the resorbed root surface by 21 days. After deposition of the new cementum, the structures of a new periodontal ligament (PDL) were comparable with the control specimens.
先前通过光学显微镜（LM）和扫描电子显微镜（SEM）已经表明，在力终止后，正畸性牙根吸收腔隙的修复是通过新牙骨质的沉积发生的。该过程的超微结构细节尚未完全明确。由于据推测在修复阶段会形成一个保护牙根表面的新屏障，因此关于正畸性牙根吸收这一方面的新信息可能很有价值。本研究的目的是通过使用透射电子显微镜（TEM），更详细地研究正畸性牙根吸收腔隙的修复以及相邻牙周膜（PM）的重建。使用了三组40 - 45日龄大鼠的实验性牙齿移动组。上颌第一磨牙通过闭合螺旋弹簧向近中移动10天、14天和21天。结果表明，即使在轻力存在的情况下，活跃的牙根吸收向修复过程的转变与成纤维细胞样细胞从周边侵入活跃的牙根吸收部位有关。10天后，在吸收腔隙的周边可见新的牙齿支持结构形成，而多核破骨样细胞（OD）在中央部分进行活跃吸收。在后期，力终止后，修复过程类似于牙齿发育过程中早期的牙骨质形成。到21天时，在吸收的牙根表面观察到新的矿化牙骨质。新牙骨质沉积后，新的牙周韧带（PDL）结构与对照标本相当。
