Journal of Oral Tissue Engineering

Effect of APF Solution on The Surface Characteristics of Dentin

Yasuaki HIROSE, Kazushi YOSHIKAWA, Masayoshi INOUE and Kazuyo YAMAMOTO

Department of Operative Dentistry, Osaka Dental University

J Oral Tissue Engin 2005;3(2): 87-96

Full Text. DOI

The present study was performed to examine the effects of acidic phosphate fluo-rine (APF) solution on the surface layer of dentin using an atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). Twenty human teeth were cut to create the dentin discs with the diameter of 3 mm. Half of the discs were highly polished. Another half of the discs were highly polished and then immersed in a demineralizing solution (pH 5.0) for 24 hours to produce the subsurface lesions. The demineralizing solution consisted of 0.1 M lactic acid, 0.2% carbopol and 50% saturated hydroxyapatite. All specimens were treated in 10 ml APF solution (2.0%) for 4 minutes. The surface of each specimen was observed with an AFM and the specimens were subjected to scans with XPS. The surface of APF-treated polished dentin was flat without closure of dentinal tubes. The crystals in the APF-treated polished dentin were more globular than polished dentin. The surface of the APF-treated demineralized dentin was rough compared to the polished dentin. The crystals were square, and their porositys were expanded. The APF treatment reduced the roughness of the surface and the crystalline porosity by dense gathering of globular and oval crystals. The relative concentration of F was increased by the APF treatment. The F/Ca atomic ratio was 0.02±0.02 in the polished dentins, 1.88±0.09 in the APF-treated polished dentins, and 1.95±0.11 in the APF-treated demineralized dentins. These results indicated that fluorine-reaction products were generated by the APF treatment of the polished dentin and demineralized dentin.

Key words:APF, Dentin, AFM observation