Assessment of the nanostructure of acid–base resistant zone by the application of all-in-one adhesive systems: Super dentin formation
Issue title: Selected papers presented at the International Symposium on Nanotoxicity Assessment and Biomedical Environmental Application of Fine Particles and Nanotubes, Hokkaido, Japan, 16–17 June 2008, Part 2
Affiliations: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan | Division of Conservative Dentistry, King's College London Dental Institute at Guy's, King's College and St. Thomas' Hospitals, King's College London, London, UK | Global Center of Excellence Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo, Japan
Note: [] Address for correspondence: Toru Nikaido, Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Tel.: +81 3 5803 5483; Fax: +81 3 5803 0195; E-mail: nikaido.ope@tmd.ac.jp.
Abstract: An acid–base resistant zone (ABRZ) has been shown to be created under a hybrid layer in a self-etching adhesive system at the adhesive/dentin interface. The purpose of this study was to assess the nanostructure of the ABRZ by applying all-in-one adhesive systems. Human premolar dentin was treated with one of two all-in-one adhesive systems; Clearfil Tri-S Bond and G-Bond according to the manufacturers' instructions. After placement of a resin composite, the bonded interface was vertically sectioned and subjected to an acid-base challenge. Following this, the nanostructure of the ABRZ was examined by SEM and TEM. The SEM observations of the adhesive-dentin interface after the acid-base challenge indicated that a hybrid layer less than 1 μm thick was created, and a ABRZ was formed beneath the hybrid layer for each adhesive system. The TEM observations indicated that the ABRZ contained mineral components in both adhesive systems, however, the thickness of the ABRZ was material dependent. The application of the all-in-one adhesive systems created an ABRZ at the underlying dentin, which reinforced normal dentin against dental caries. Therefore, this zone was named ‘Super Dentin’. Formation of ‘Super Dentin’ is a new approach in caries prevention.
