Hall R K, Manière M C, Palamara J, Hemmerlé J
University of Melbourne, Royal Children's Hospital, Melbourne, Australia.
Connect Tissue Res. 2002;43(2-3):401-5. doi: 10.1080/03008200290001005.
The inherited dentin defect dentinogenesis imperfecta (DI), while clinically obvious in osteogenesis imperfecta (OI) Types IB and IC, II, III, and IVB, is now thought to be present in all children with OI, in a continuum from minimal to severe dentin pathology. This collaborative study further clarifies the structural and ultrastructural dentin changes in the teeth of OI children with clinically obvious DI, and attempts to explain these in terms of odontoblast dysfunction. Collaborative studies were carried out in Melbourne, Australia, and Strasbourg, France, using light and polarized-light microscopy, scanning and transmission electron microscopy (SEM, TEM), selected-area diffraction (SAD), and x-ray spectroscopy (EDX). These showed structurally normal enamel (but containing long and broad lamellae) and a normally scalloped dentino-enamel junction (DEJ), but severe pathologic changes in the dentin. An initial narrow band of normal-appearing dentin tubules (including the mantle layer) ceased abruptly and was replaced by a wavelike laminar zone parallel to the DEJ with occluded tubules. Multiple parallel channels of 5-10 microns diameter were present at right angles to the DEJ indenting this zone, some terminating in retro-curved "processes." The abnormal dentin containing these channels almost completely occluded the pulp chamber. The structural and ultrastructural changes seen can be explained on the basis of the collagen defect in OI resulting in odontoblast dysfunction, which produces a distinct phenotype and one that is different from that in bone.
遗传性牙本质缺陷——牙本质发育不全（DI），虽然在成骨不全（OI）的IB型、IC型、II型、III型和IVB型中临床症状明显，但现在认为所有OI患儿都存在这种情况，从轻微到严重的牙本质病理变化呈连续状态。这项合作研究进一步阐明了患有临床明显DI的OI患儿牙齿中牙本质的结构和超微结构变化，并试图从成牙本质细胞功能障碍的角度对此进行解释。在澳大利亚墨尔本和法国斯特拉斯堡开展了合作研究，使用了光学显微镜和偏光显微镜、扫描和透射电子显微镜（SEM、TEM）、选区衍射（SAD）和X射线光谱（EDX）。这些研究显示釉质结构正常（但含有长而宽的釉板）以及正常的扇贝状牙本质-釉质界（DEJ），但牙本质存在严重的病理变化。最初一条窄带的外观正常的牙本质小管（包括罩牙本质层）突然终止，取而代之的是一个与DEJ平行的波浪状层状区域，其中小管闭塞。存在多条直径为5 - 10微米的平行通道，与DEJ成直角并切入该区域，一些通道终止于向后弯曲的“突起”。含有这些通道的异常牙本质几乎完全阻塞了牙髓腔。所观察到的结构和超微结构变化可以基于OI中的胶原蛋白缺陷导致成牙本质细胞功能障碍来解释，这产生了一种独特的表型，且与骨骼中的表型不同。
