Sorption and solubility of self-etching adhesives immersed in organic acids present in oral biofilm.

This study evaluated the sorption and solubility of self-etching adhesive systems after immersion in distilled water, lactic acid, and propionic acid. Specimens of 2 two-step (P90 System Adhesive [P90], Clearfil SE Bond [CSE]) and 1 single-step (Adper Easy One [AEO]) adhesive systems were prepared and divided into 4 groups: P90 primer ( P90-P), P90 bond (P90-B), AEO, and CSE bond (CSE-B). Specimens were placed in a desiccator and weighed daily until achieving a constant mass (m1). The specimens (n = 5) were then immersed in the respective media and weighed until a achieving a constant mass (m2). The specimens were again desiccated (m3). Sorption and solubility data were analyzed with two-way ANOVA and Turkey's test. Specimens were also observed using SEM without immersion, after 24 h, and at the end of the respective total time of immersion. For all immersion media, the highest sorption values were obtained for AEO and P90-P, followed by CSE-B and P90-B, which presented the lowest sorption. The time required for adhesives to absorb the solutions was: 11 to 19 days for P90-P, 12 to 13 days for P90-B, 15 to 19 days for AEO, and 14 to 18 days for CSE-B. The highest values of solubility were shown for AEO and P90-P in all immersion media. In water and propionic acid, the adhesives with the lowest solubility values were CSE-B and P90-B. CSE-B had the lowest solubility in lactic acid. The greatest surface degradation was observed after each respective total time of immersion. AEO specimens presented more evident surface degradation and the highest sorption and solubility.