Adhesion of various types of dental resin cements to the dentin of the tooth crown and root

我们先前发现，除Super Bond外的树脂粘固剂在牙根的牙本质上的粘结强度低于牙冠，使用的是我科附属牙科医院拔除的无龋牙和修复体。对除SuperBond外的树脂粘固剂底漆处理的牙面进行了电子显微镜观察，证实了牙根表面存在大量的涂抹层。此外，在牙冠中形成的树脂标签较长且致密。这些发现表明，树脂标签影响粘接强度。树脂标签的形成取决于切割后引起的涂抹层的去除程度，即当去除涂抹层的效果较大时，容易形成树脂标签。因此，这些结果表明，即使在相同的处理时间内使用相同的处理剂，污渍层…的去除程度也存在差异最近我们确认了涂抹层的差异，并进行了实验，以确定这种差异是否由牙冠和牙根的成分不同造成的。首先，为了确认最近开发的微焦点X射线CT系统(岛津公司)。为了达到这些目的，我们初步拍摄了牛牙的X光照片。结果，我们充分观察到了牙冠和牙根钙化程度的差异，目前我们正在对人类牙齿进行研究。对于底漆处理程度和树脂浸渍层厚度的差异，我们使用Eleonics公司的超微压痕硬度测试仪：Eleonics Corp.)，每隔2 nm测量牙本质的硬度。虽然没有观察到树脂浸渍层之间的差异，但树脂浸渍层下的牙本质被处理在牙根更深的地方。因此，粘结强度的差异很可能取决于处理层和涂抹层形成程度的差异，这是由于牙冠和牙根的成分不同造成的。较少

We previously found that the bond strength of resin cements except Super Bond on the dentin of the tooth root was lower than that of the tooth crown, using teeth without caries and restorations that were extracted in the dental hospital attached to our department. By electron microscopic observation of the tooth surface treated by the primer of the resin cements except Super Bond, the presence of many smeared layers on the tooth root surface were confirmed. Furthermore, the formed resin tags were long and dense in the tooth crown. These findings suggested that resin tags influenced bond strength. The formation of resin tags depends on the degree of the removal of smeared layers caused after cutting, that is, when the effect of the removal of smeared layers is large, resin tags can be easily formed. Therefore, these results indicated that even if the same treatment agent was used for the same treatment duration, there were differences between the degree of the removal of smeared layers … More in the tooth crown and that of the tooth root, and these differences influenced the bond strength.We recently confirmed the differences in the smeared layers, and performed experiments to confirm whether the differences were caused by the difference between the component of the tooth crown and that of the tooth root. First, to confirm that a recently developed micro-focus X-ray CT system (Shimazu Corp.) was useful for these purposes, we preliminarily took X-ray of bovine teeth. As a result, differences between the degree of calcification in the tooth crown and that of the tooth root were sufficiently observed, and we are investigating human teeth at present. In regard to the differences in the degree of primer treatment and the thickness of resin-impregnated layers, we measured the hardness of dentin at intervals of 2 nm from the adhesion interface, using an ultra-micro indentation hardness test apparatus : ENT-1100a (Eleonics Corp.). Although no differences in the resin-impregnated layers were observed, the dentin under the resin-impregnated layers was treated deeper in the tooth root. Therefore, there was a strong possibility that differences in bond strength were dependent on the differences in the degree of the formation of treated layers and smeared layers, which were caused by the difference between the component of the tooth crown and that of tooth root. Less