Methods:The labial surfaces of seventy bovine incisors were polished with 600-grit silicon carbide paper on a water-irrigated metallurgical polishing wheel. The specimens were randomly divided into seven groups. 1) bleaching (10% Rembrandt Xtra-Comfort + immersed in artificial saliva for seven days. 2) bonded immediately after bleaching. 3) bleaching + 10% sodium ascorbate (SA) gel for 10 minutes. 4) bleaching + 10% sodium ascorbate (SA) gel for 60 minutes. 5) bleaching + 10% sodium ascorbate (SA) gel for 120 minutes. 6) bleaching + 10% sodium ascorbate (SA) gel for 240 minutes. 7) bleaching + 10% sodium ascorbate (SA) gel for 480 minutes. After bonding application, the resin composite in standard dimensions was applied to all specimens. The teeth were stored in distilled water at 37¢ªC for 24 hours and a universal testing machine determined their resistance to shear bond strength. The data were evaluated using ANOVA and Tukey tests.
Results:Antioxidant gel application to the bleached enamel was proven to be effective in the increase of the shear bond strength of composite resin to enamel. Antioxidant gel should be applied on the enamel for at least 60 minutes in order that it could be effective enough. As the application period of the antioxidant on the enamel has increased, the bond strength of the composite on enamel tissue has also increased. The increase noticed in the groups 5,6, and 7 is statistically significant (P<0.05).
Conclusions:The applicability of the process by the patient himself shortens the time period spent in the clinic.