Comparative Analysis of Sodium Ascorbate, Açai Berry Extract, and Theaflavin on Shear Bond Strength of Metal Brackets Following Enamel Bleaching

Aim and Objectives: The study aimed to analyze and compare the shear bond strength (SBS) of metal brackets bonded to bleached enamel treated with different antioxidants. The objectives were to assess SBS in unbleached enamel, bleached enamel, and bleached enamel treated with Açai Berry extract, Sodium Ascorbate, and Theaflavin, and to compare their effectiveness in restoring SBS.  Materials and Methods: 60 extracted human first premolars were randomly assigned to five groups (n=12):  Group I: Control (unbleached, bonded)  Group II: Bleached with 35% hydrogen peroxide  Group III: Bleached + 10% Açai Berry extract  Group IV: Bleached + 10% Sodium Ascorbate  Group V: Bleached + 10% Theaflavin Antioxidants were applied for 10 minutes after bleaching. Brackets (MBT 0.022” slot, 3M Unitek) were bonded with Transbond XT adhesive. SBS was tested after 24 hours using a Universal Testing Machine, and results were analyzed with one-way ANOVA and Tukey’s post-hoc test (p < 0.05).  Results: Mean SBS values (MPa) were: Group I (25.9), Group II (6.1), Group III (19.2), Group IV (14.1), and Group V (23.9). Statistical analysis showed bleaching significantly reduced SBS (p < 0.001). All antioxidants improved SBS compared to the bleached group. Theaflavin restored SBS values closest to the control, followed by Açai Berry, while Sodium Ascorbate was least effective.  Conclusion: Bleaching significantly compromises bracket bond strength. Antioxidants effectively restore SBS, with Theaflavin demonstrating the best performance, nearly equivalent to unbleached enamel, followed by Açai Berry and Sodium Ascorbate. Antioxidant pretreatment can be recommended to enhance bonding efficiency after bleaching.