ULTRASTRUCTURAL-CHANGES IN ODONTOBLASTS AND PULP CAPILLARIES FOLLOWING CAVITY PREPARATION IN RAT MOLARS
ULTRASTRUCTURAL-CHANGES IN ODONTOBLASTS AND PULP CAPILLARIES FOLLOWING CAVITY PREPARATION IN RAT MOLARS
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DOI：
10.1679/aohc.53.423
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发表时间：
1990-10-01
影响因子：
--
通讯作者：
OHSHIMA, H
中科院分区：
文献类型：
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作者：
OHSHIMA, H
采用光镜和透射电镜观察了大鼠上第一磨牙成牙细胞和牙髓毛细血管对造腔的反应。100日龄时，牙髓血管在离成牙层不远的地方形成了由连续的毛细血管组成的成牙内膜网络。空腔制备导致一些成牙本质细胞移位到牙本质小管中，而另一些则在钻孔后通过快速炎症渗出与前牙本质分离。损伤牙本质下的成牙细胞毛细血管网随分离的成牙细胞一起向内移位。移位的毛细血管内皮显示胞饮性囊泡的显著增加，这一事件被认为与渗出性病变的形成密切相关。在造腔后1天，大部分受损的成牙细胞发生了退化。许多高核/细胞质（N/C）比的细胞和突出的核仁聚集在成牙釉质下毛细血管周围，其中一些毛细血管有许多内皮窗。这些细胞提示新近分化的成牙细胞接受毛细血管的营养供应。空腔制备3天后，新生分化成牙髓细胞取代了退化的成牙髓细胞。预备牙槽5天后开始产生修复性牙本质。毛细血管位于新生成牙细胞下方，但内皮孔的数量逐渐减少。在主动修复牙本质形成过程中，毛细血管紧密地保持在新生成牙本质层的下方。虽然修复性牙本质沉积率并不明显低于原生牙本质形成时的沉积率，但我们不能发现毛细血管侵入成牙本质层，也不能发现内皮孔的显著增加，而这两种情况在原生牙本质形成过程中都很常见。结果表明，初级牙本质与修复牙本质形成过程中毛细血管的功能存在差异。
Responses of odontoblasts and pulp capillaries to cavity preparation were investigated in the upper first molar teeth of rats, using light and transmission electron microscopy. At 100 days of age, the blood vessels of the pulp formed a subodontoblastic network consisting of continuous capillaries at a short distance from the odontoblast layer. Cavity preparation caused the displacement of some odontoblasts into the dentinal tubules, while others were separated from the predentin by rapid inflammatory exudation after drilling. The subodontoblastic capillary network under the injured dentin was shifted inwards together with the separated odontoblasts. The endothelium of the shifted capillaries showed a remarkable increase of pinocytotic vesicles, an event thought to be closely related to the formation of the exudative lesion. By one day after cavity preparation, most of the damaged odontoblasts had degenerated. Many cells with high nucleus/cytoplasm (N/C) ratios and prominent nucleoli accumulated around the subodontoblastic capillaries, some of which had many endothelial fenestrae facing these cells. These cells were suggestive of newly differentiating odontoblasts receiving nutritional supply from the capillaries. Three days after cavity preparation, newly differentiating odontoblasts took the place of the degenerated odontoblasts. They began to produce reparative dentin by five days after cavity preparation. Capillaries were located beneath the newly differentiating odontoblasts, but endothelial fenestrae gradually decreased in number. During the active reparative dentin formation, capillaries remained closely beneath the new odontoblast layer. Although the rate of reparative dentin deposition was not significantly lower than that in the primary dentin formation, one could not recognize an invasion of capillaries into the odontoblast layer nor a remarkable increase of endothelial fenestrae, both of which are common in active primary dentin formation. The results suggest that the function of capillaries differs between primary and reparative dentin formation.