Effects of drying agents on bond strength of etch-and-rinse adhesive systems to enamel immediately after bleaching.
OBJECTIVE
To determine the effect of drying agents and adhesive solvents on the bond strength of resin composite to enamel immediately after bleaching.


METHODS
Sixty healthy human premolars were bleached using 15% carbamide peroxide gel and randomly divided into three groups according to the immersing solutions applied immediately after bleaching: 70% alcohol, acetone, and distilled water. Each group was randomly divided into two subgroups according to the adhesives that were applied: an alcohol-based adhesive (Single Bond) and an acetone-based adhesive (One Step). By using rubber washers, composite Z100 was placed onto the enamel and shear bond strength was evaluated in a universal testing machine at a crosshead speed of 1 mm/min. The type of failure was also assessed using a stereomicroscope. The data were statistically analyzed by two-way ANOVA and Tukey's post-hoc test (α = 0.05). Fisher's Exact test was used to evaluate differences in the failure modes.


RESULTS
Statistical analysis showed that the bond strength of the distilled water groups was significantly lower than that of the other groups, but the bond strengths of the two groups where a drying agent was applied were similar to that of the unbleached group. The acetone-based adhesive (One Step) provided higher bond strength than did the alcohol-based adhesive (Single Bond) (p < 0.05). There was no interaction between the two variables (p > 0.05). Fisher's Exact test showed there was no significant difference in the failure mode of all the experimental groups (p > 0.05).


CONCLUSIONS
The application of drying agents improves the bond strength of resin composite to bleached enamel. Furthermore, the acetone-based adhesive used in the study had a higher bond strength to bleached enamel than did the alcohol-based adhesive used.
Department of Operative Dentistry, Mashhad University of Medical Science, Iran.
Alireza Boruzi
AB
Niat
Fatmeh Maleknejad
FM
Yazdi
Niloufar
N
Koohestanian
D000134:Acid Etching, Dental; D001840:Dental Bonding; D003743:Dental Enamel; D017220:Dentin-Bonding Agents / Q000737:chemistry; D003890:Desiccation; D006801:Humans; D006858:Hydrofluoric Acid; D019279:Resin Cements / Q000737:chemistry; D012997:Solvents; D013718:Tensile Strength; D014073:Tooth Bleaching; D014465:Ultrasonics; D014867:Water
D017220:Dentin-Bonding Agents; D019279:Resin Cements; D012997:Solvents; D014867:Water; D006858:Hydrofluoric Acid