牙本质龋损下牙本质-牙髓复合体的反应

Dentin-pulp complex's responses to dentin caries

目的探讨牙本质龋损进展过程中,牙本质-牙髓复合体的变化特点及规律。方法选择即刻拔除的第三磨牙65颗,其中牙本质浅龋27颗(急性龋15颗,慢性龋12颗);牙本质深龋28颗(急性龋16颗,慢性龋12颗);无龋损的正常牙10颗。常规固定、脱钙、切片(厚4μm),光学显微镜下观察牙本质龋病损下方牙髓的组织病理学改变,并用多功能图象分析仪对相应部位的成牙本质细胞的数目、浆核比、前期牙本质面积等进行测量分析。结果随龋损深度的增加,成牙本质细胞数目显著减少,细胞形态由高柱状变为立方状直至扁平状,前期牙本质变薄甚至消失,第三期牙本质变厚且发生率增加,血管扩张充血,炎症细胞增多,主要为淋巴细胞与浆细胞;牙本质浅龋阶段,成牙本质细胞浆核比显著下降,慢性龋成牙本质细胞样细胞分化、迁移活跃,胶原纤维增多。牙本质深龋阶段出现修复性牙本质,急性龋炎症细胞聚集明显。结论牙本质-牙髓复合体对龋损的反应与龋损深度及活动性有关;龋损深度增加,损伤反应加重;龋损活动性降低时修复与防御反应加强。

Objective To observe the dentin-pulp complex＇s responses to dentin caries progression. Methods A total of 65 third molars were collected immediately after extraction, of which 27 teeth with shallow dentin caries including 15 acute caries and 12 chronic caries, 28 with deep dentin caries including 16 acute caries and 12 chronic caries, and 10 without caries. The teeth were fixed, demineralized and sectioned at a thickness of 4 μm , which were then subjected to HE staining and cellular reactions to the lesion were measured using computerized histomorphometry to examine： ①the number of odontoblast; ②the cytoplasm： nucleus ratio of the odontoblast cells; ③the adjacent predentine area; ④the thickness of tertiary dentin. Results As carious lesion approached the pulp ,the number of odontoblast cells significantly reduced , the cell shape changed from columnar to cubic or even flattened, predentin area reduced or even disappeared, inflammatory cells mainly lymphocytes and plasma cells increased with hyperemia. In shallow carious stage, the cytoplasm： nucleus ratio of the odontoblast cells decreased significantly, odontoblast-like cells and collagen fibers were seen in chronic cases. In deep caries , subodontoblastic region was sometimes infiltrated by many inflammatory cells and engorged capillaries were seen there, tertiary dentine often without tubular structure were formed. Conclusion The difference of the dentin-pulp complex＇s responses to the dentin caries is associated with the depth and activity of carious lesion.