Ascorbic acid influence on resin-dentin bond resistance to degradation

Objective: To determine the resin-dentin bond resistance to degradation of two adhesive systems after the addition of ascorbic acid (AA) on their formulation. Methods: Flat dentin surfaces from forty-eight human molars were bonded according to manufacturer's instructions with an etch-and-rinse (Single Bond-SB) and a self-etch (Clearfil SE Bond-CSE) adhesive system: 1) with the original manufacturer's composition; 2) after addition of 10% AA on the primer/resin formulation. Bonded specimens were sectioned into 1.0 mm² beams and tested after 24h, after immersion in 10% NaOCl for 5 h, and after 1 or 4 years storing in distilled water. Beams were tensioned at 0.5 mm/min. Results were analyzed by ANOVA and SNK tests (P<0.05). Debonded surfaces were observed by SEM. Results: Mean microtensile bond strength (MTBS) and standard deviations are listed (MPa). Letters indicate differences in columns and numbers in rows.