Method: The products tested were: Adhese Universal (ADU), Prelude One (PRO) and Prime & Bond Elect (PRE).The properties tested were: a) %DC, by ATR-FTIR spectroscopy (n:5, 100μm thick specimens, 30s exp 1,2W/cm2 light intensity, +5min storage at 37oC), b) OI, by transmission optical microscopy (n:5, conditions as before) and c) assessment of the dentine demineralization capacity (%DM) by ATR-FTIR spectroscopy ( n:5, 10 min unset adhesive in contact with dentine, calculation of the mineral to matrix ratios of smear-layer covered dentine before and after adhesive treatments plus acetone rinsing to remove the soluble components) and identification of spectral changes in comparison with original dentine. Statistical analysis was performed by one-way ANOVA and Tukey test (a:0.05).
Result: The %DC values recorded were (mean±standard deviation): ADU (78.2±4.9), PRO (40.9±6.4) and PRE (61.5±5.6) with all means statistically significant different. For OI , PRO showed the lowest value (5.6±0.2 microns, p<0.05) in comparison with ADU (10.0±0.1) and PRE (11.2±0.2). The %DM after all adhesive treatments was mild (12-22%) with some residual adhesive peaks found on dentine, which may support irreversible adsorption of adhesive components onto dentine.
Conclusion: The adhesives tested showed differences in conversion, O2 inhibition and demineralization capacity, anticipating thus variations in their clinical performance. Identification of irreversibly adsorbed species implies the possibility of establishment of a bonding condition at the interface.