Observation of bonded interface of vital dentin and a composite resin

• Published in: Adhesive Dentistry Vol. 20; no. 3; pp. 119 - 127
• Main Authors: NAKAZAWA, Yuichi, HIRAI, Yoshito, ISHIKAWA, Tatsuya
• Format: Journal Article
• Language: Japanese
• Published: Japan Society for Adhesive Dentistry 2002
• Subjects: bacterial growth; gap; hybridized dentin; vital cavity wall
• ISSN: 0913-1655; 2185-9566
• DOI: 10.11297/adhesdent1983.20.119

The purpose of this investigation is to examine the bonded interface restored to adultdog teeth with resin-composite by scanning electron microscope (SEM). The Class V cavities prepared were acid conditioned with 40% phosphoric acid gel (K-etchant; Kuraray), applied adhesive primer (Clearfil Photo Bond; Kuraray) and restored with a resincomposite (Clearfil Photo Posterior; Kuraray). After seven days (short-term) and 90 days (long-term), these teeth were extracted, and observed the bonded interface with SEM. As the result, the junction was very tight between the enamel and resin-composite in both short- and long-term period. The junction between the dentin and resin-composite was also tight in the short-term period. In the long-term specimen, on the other hand, exfoliation was partially observed in the region along the dentinal wall, and bacterial cells were detected in the exfoliated gap area. However, high-magnification SEM view of that area showed that the hybridized dentin continues to seal the underlying mineralized dentin. These results suggested that the hybrid layer dose not permit invasion of stimuli such as microorganisms and their products to the pulp, which were histologically intact. Thus, we concluded that the hybridized dentin functioned as barrier of dentin/pulp complex from external stimuli like enamel.