Gurling F G, Sampson W J
Arch Oral Biol. 1985;30(11-12):757-64. doi: 10.1016/0003-9969(85)90128-1.
The ultrastructure of the epithelial root-sheath was examined in the first mandibular molar teeth of 11, 16 and 21-day-old mice. The changing morphology of the sheath was related to root maturity. An initial, predominantly bicellular layer progressively shortened in an apical direction, the outer layer more so than the inner. The changing morphology appeared to involve maintenance of the inner layer largely at the expense of the outer. Some inner-layer cells persisted at spaced intervals adjacent to forming acellular cementum. Some epithelial rests, distant from the root surface, appeared to be formed early in root development at the time of initial root-sheath severance from the cervical loop of the enamel organ. Epithelial rests located along the acellular cementum appeared to arise from inner, rather than outer, epithelial root-sheath cells and at later stages in root development.
对11日龄、16日龄和21日龄小鼠的下颌第一磨牙的上皮根鞘超微结构进行了检查。鞘形态的变化与牙根成熟度有关。最初主要为双细胞层，在根尖方向逐渐缩短，外层比内层缩短得更多。形态变化似乎主要是以内层的保留为代价来维持外层。一些内层细胞以间隔的方式持续存在于正在形成的无细胞牙骨质附近。一些远离牙根表面的上皮剩余似乎在牙根发育早期，即上皮根鞘最初从釉器颈环分离时形成。沿无细胞牙骨质分布的上皮剩余似乎起源于上皮根鞘的内层细胞，且发生在牙根发育的后期阶段。
