Development and Histopathologic Features of Odontoclastic Resorption on the Internal Dentin Wall after Replantation of Rat Molars

人类牙列内牙根吸收的病因、发病机制和预后仍有待进一步了解。本研究旨在建立大鼠磨牙近中根根尖周渗透泵局部灌注化学药物的模型。雄性Sprague-Dawley大鼠（6周龄，200 g b.w.）用了在全身麻醉下的外科手术中，借助小的牙科棒（根尖切除术）去除内侧根的顶端，留下一个穿过皮质骨的钻孔（直径约0.8 mm）。将装载200 μL药物溶解溶液（或仅溶剂作为对照）的泵皮下植入背侧区域，并将套管置于磨牙区域的钻孔中（局部输注）。在基金期间获得的结果证明，大鼠磨牙模型是有用的研究牙本质内吸收。再植磨牙的组织学检查显示 关于我们 牙再植术后第7天牙本质内壁TRAP阳性多核细胞出现吸收陷窝。吸收陷窝分为A型和B型，分别对应于表面型和炎性型外根吸收。导致内部牙本质吸收发展的基本事件是先天牙髓组织被肉芽组织的向内生长以及包括巨噬细胞和成纤维基质细胞的新细胞群的组装所取代。破牙细胞与前牙本质壁的初始附着不一定需要OPN预处理，并且似乎是由替代识别机制介导的。这些结果支持了大鼠磨牙先天牙髓对不良吸收活动具有抑制作用的假设，但在再植后先天牙髓环境受损后，细胞-基质和细胞-细胞相互作用的新范式可能协同作用，诱导内predintin/牙本质壁的碎屑活动。少

The etiology, pathogenesis and prognosis of internal root resorption in human dentition remain to be better understood. We aimed at establishing rat molar model combining an osmotic pump for local-infusion of chemical agents into the periapical region of the mesial root of upper first molars. Male Sprague-Dawley rats (6-wk-old, 200g b.w.) were used. At the surgical operation under general anesthesia, the apical end of the medial root was removed with the aid of a small dental bar (apicoectomy), leaving a drilled hole (around 0.8mm in diameter) through cortical bone. The pump loading 200 μL of an agent-solubilized solution (or vehicle only as control) was implanted subcutaneously on the dosal area and the cannula was placed into the drilled bony hole in the molar region (local-infusion). The results obtained during the funding period prove that rat molar model is useful for investigation of internal dentin resorption. Histologic examination of the replanted molars showed the occurrence … More of resorption lacunae accompanying TRAP-positive multinuclear cells on the internal dentin wall around day 7 after tooth replantation. Resorption lacunae were classified into A and B types, which appeared to correspond to surface and inflammatory types of external root resorption, respectively. The essential event responsible for the development of internal dentin resorption is the replacement of the innate pulp tissue with the ingrowth of granulation tissue and the assembly of a new cell population comprising macrophages and fibroblastic stromal cells. The initial attachment of odontoclasts to the predentin wall does not necessarily need preconditioning with OPN and appears to be mediated by alternative recognition mechanisms. The overal results support the hypothesis that the innate pulp of rat molars possesses in potency inhibitory functions against undesirable resorption activities, but after impairment of the innate pulp environment after tooth replantation, a new paradigm of cell-matrices and cell-cell interactions may act cooperatively to induce clastic acitivities on the internal predintin/dentin wall. Less