Effects of pathobiology of dentin/pulp complex to adhesive restorative techniques

本研究采用Beagle犬和磨牙的牙本质楔型和盒型洞，在体内外研究了现有粘结树脂的微拉伸粘结强度，并通过扫描电镜、透射电镜、XMA和西姆斯，以阐明牙本质/牙髓复合体的病理学作用。Clearfil Liner Bond II（LBII）和Imperva Fluoro Bond（FB）填充后，两种自酸蚀粘接剂对牙本质的MTBS均大于30 MPa，且在体与离体之间无显著性差异（p<0.05）。但充填3周后，两种系统的MTBS均出现明显下降，均小于20 MPa，充填3个月后MTBS相对稳定（20 MPa左右）。扫描电镜和透射电镜观察表明，充填后即刻体内混合层形成清晰，3个月后未见混合层形成。与抗微管蛋白抗体反应的管状结构的存在抑制了树脂标签的形成。西姆斯显示氟离子在体内3个月后渗入到FB粘结的牙本质中，并在体外精确检测了龋病对树脂-牙本质粘结的影响，Single bond（SB）对正常牙本质的MTBS最高可达40 MPa以上，而SB对龋病牙本质的MTBS明显低于正常牙本质。SB、LB、FB对龋蚀牙本质的平均剪切强度均小于20 MPa，而树脂可部分包埋龋蚀菌，提示粘接树脂对龋蚀牙本质进行封闭修复的可能性。

We investigated the microtensile bond strengths (MTBS) of current adhesive resins to dentin wedge-shaped and box-form cavities of beagle dog canines and molars in vivo and in vitro, and observed the interfacial morphology of resin-bonded dentin by SEM, TEM, XMA and SIMS so as to clarify the effects of pathobilogy of dentin/pulp complex.After filling of Clearfil Liner Bond II (LBII) and Imperva Fluoro Bond (FB) to dentin in vivo, both self-etching adhesive systems could show high MTBS more than 30MPa, and there were no significant differences between the MTBS in vivo and in vitro (p<0.05). However, 3 weeks later after filling, the MTBS of both systems showed significant decrease less than 20MPa, and 3 months later the MTBS were relatively stable (about 20MPa). The SEM and TEM showed that the formation of hybrid layers in vivo was clear immediately after filling, but 3 months later, hybri layers could not be seen. The resin tag formation were inhibited by the presence of the tube-like structures which reacted with anti-tubulin antibody. SIMS showed the penetration of fluoride ions into the subsurface dentin bonded with FB in vivo 3 months later.Moreover, we examined the effects of caries to resin-dentin bonding in vitro precisely, and Single bond (SB) could show the highest MTBS to normal dentin more than 40MPa, but the MTBS of SB to caries-affected dentin was significantly lower than that to normal dentin. The MTBS of SB, LB, FB to caries-infected dentin were less than 20MPa, however, carious bacteria could be partially embeded with resins, and these results suggested the possibility of sealed restoration to caries-infected dentin with adhesive resins.