Tziafas D, Kolokuris I, Alvanou A, Kaidoglou K
Department of Dental Pathology and Therapeutics, School of Dentistry, Aristotelian University of Thessaloniki, Greece.
Arch Oral Biol. 1992 Feb;37(2):119-28. doi: 10.1016/0003-9969(92)90007-u.
The events initiating the expression of odontoblastic potential by pulpal ectomesenchymal cells were investigated by exposing the pulp to demineralized, native and unmineralized autogenous dentine. The pulp responses to implants were histologically evaluated 3, 7 and 10 days postoperatively, while the surface structure of the newly mineralized matrices was examined 12 and 28 days after implantation. Differentiation of odontoblast-like cells in close proximity to the implanted matrix was consistently demonstrated after exposure to predentine. Scattered columnal cells undergoing polarization, characterized ultrastructurally by the orientation of their rough endoplasmic reticulum, were also found in direct contact with the demineralized dentine. However, in response to demineralized implants, groups of differentiated odontoblast-like cells were clearly seen only in association with a zone of matrix secreted in a polar, predentine-like pattern, indicating an asynchronous inductive influence of this type of implant on pulp cells. Further, the response of pulp cells to native dentine was characterized by the elaboration of a two-layered matrix (a fibrous and a polarly deposited matrix) before initiation of secondary dentinogenesis. Scanning electron microscopy of the newly deposited matrices revealed differences between the indirect matrix synthesis, observed in short-term response to implants of demineralized or native dentine, and the specific, dentinogenic function of the odontoblast-like cells. These observations indicate that the dentine-induced dentinogenesis is initiated by two mechanisms--direct induction of odontoblast-like cells as well as indirect matrix synthesis, which further controls cell polarization. Immobilization of the cells on implanted matrix seems to be the critical requirement for direct expression of the odontoblastic phenotype.
通过将牙髓暴露于脱矿质、天然和未矿化的自体牙本质，研究了启动牙髓间充质细胞牙本质形成潜能表达的事件。术后3、7和10天对牙髓对植入物的反应进行组织学评估，而在植入后12和28天检查新矿化基质的表面结构。暴露于前期牙本质后，始终能证明在植入基质附近有成牙本质样细胞的分化。在与脱矿质牙本质直接接触的区域也发现了散在的柱状细胞发生极化，其超微结构特征是粗面内质网的取向。然而，对于脱矿质植入物，仅在与以极性、前期牙本质样模式分泌的基质区域相关联时，才能清楚地看到成牙本质样细胞的分化群，这表明这种类型的植入物对牙髓细胞有异步诱导影响。此外，牙髓细胞对天然牙本质的反应特征是在继发性牙本质形成开始之前形成两层基质（一层纤维性基质和一层极性沉积基质）。对新沉积基质的扫描电子显微镜观察揭示了在对脱矿质或天然牙本质植入物的短期反应中观察到的间接基质合成与成牙本质样细胞的特定牙本质形成功能之间的差异。这些观察结果表明，牙本质诱导的牙本质形成是由两种机制启动的——成牙本质样细胞的直接诱导以及间接基质合成，后者进一步控制细胞极化。细胞固定在植入基质上似乎是直接表达成牙本质细胞表型的关键要求。
