Fourier transform infrared photoacoustic spectroscopy study of physicochemical interaction between human dentin and etch-&-rinse adhesives in a simulated moist bond technique

Abstract

The purpose of this study was to provide the physicochemical interactions at the interfaces between two commercial etch- & -rinse adhesives and human dentin in a simulated moist bond technique. Six dentin specimens were divided into two groups (n = 3) according to the use of two different adhesive systems: (a) 2-hydroxyethylmethacrylate (HEMA) and 4-methacryloxyethyl trimellitate anhydrate (4-META), and (b) HEMA. The Fourier transform infrared photoacoustic spectroscopy was performed before and after dentin treatment with 37% phosphoric acid, with adhesive systems and also for the adhesive systems alone. Acid-conditioning resulted in a decalcification pattern. Adhesive treated spectra subtraction suggested the occurrence of chemical bonding to dentin expressed through modifications of the OH stretching peak (3340 cm -1 ) and symmetric CH stretching (2900 cm -1 ) for both adhesives spectra; a decrease of orthophosphate absorption band (1040 to 970 cm -1 ) for adhesive A and a better resolved complex band formation (1270 to 970 cm -1 ) for adhesive B were observed. These results suggested the occurrence of chemical bonding between sound human dentin and etch- & -rinse adhesives through a clinical typical condition. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).