Bonding to dentin. Clues to the mechanism of adhesion.

PURPOSE To investigate the effect on shear bond strength of the presence or absence of the demineralized collagen layer on both wet and dried etched dentin surfaces. MATERIALS AND METHODS Composite cylinders were mounted on dentin surfaces after the following treatments; 37% etch/wet, 37% etch/dry, 37% etch/NaOCl/wet, 37% etch/NaOCl/dry, No-etch/wet, No-etch/dry, No-etch/NaOCl/wet, No-etch/NaOCl/dry. 24-hr shear bond strength data was obtained. SEM examinations of various surfaces were also conducted. RESULTS Wet bonded specimens had significantly higher shear bond strengths, with or without the presence of the demineralized collagen layer, whether they were acid-treated or not. Acid-etched specimens had significantly higher shear bond strengths than unetched specimens.