| Research Abstract |
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.
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