Exposed cementum - morphology, characteristics and biological role in dental disease

从不同角度探讨牙周牙髓病变对牙骨质的影响及牙骨质的生物学意义。此外，对牙周手术后新牙骨质的形成进行了组织病理学和临床分析，X-射线显微分析结果显示裸露的牙骨质表面钙化，可能是受牙槽环境的影响。扫描电子显微镜观察表明，表面层的形态变化不是一个恒定的特征，变化的程度非常有限。观察到细菌内毒素已渗透到牙骨质暴露的表面。在暴露的牙骨质下，牙本质的显微硬度下降。与生牙相比，非活体牙新牙骨质形成延迟。体外培养的成纤维细胞粘附性良好，当去除根面平整过程中暴露的牙骨质仅限于表层，且有剩余的牙骨质时。此外，当牙本质暴露时，可以观察到细菌通过牙本质小管从口腔环境中渗透。尽管对牙骨质的特性有了一些新的观察，但仍有几个问题有待进一步研究。

The effects of periodontal and pulpal pathosis on cementum and the biological significance of cementum were investigated from various aspects. In addition, analysis on new cementum formation after periodontal surgery was performed histopathologically and clinically.As the results from X-ray microanalyzer study, the surface calcification of exposed cementum were observed, possibly by the influences from pocket environment. The scanning electron milcroscopical examination showed that the morphological changes did not give a constant feature and were very limited extent in the surface layers. Bacterial endotoxin was observed to be penetrated into the surface of the exposed cementum. Decrease in microhardness was seen to occur in the dentin under the exposed cementum. New cementum formation was delayed in non-vital teeth as compared to vital teeth.Adherence of cultured fibroblast cells in in vitro study was favorably observed when removal of exposed cementum in root planing procedure was limited only to the surface layer and there was remaining cementum. Furthermore, when dentin was exposed, the bacterial penetration from oral environment was observed through the dentinal tubules.Although some new observations concerning the characteristics of the cementum were established, several problems are still left for further study.