Comparative Evaluation of The Effect of Various Remineralizing Agents on Surface Microhardness of Enamel Following In-Office Bleaching: An in Vitro Study

Abstract Aim: To evaluate and compare the effect of FluoroDip Bioactive, Ultra EZ, and Dente 91 toothpaste on the surface microhardness of enamel following in-office bleaching with 35% hydrogen peroxide. Materials and Methods: Forty extracted human incisor teeth were prepared and randomly divided into four groups (n=10). Baseline enamel surface microhardness was recorded using a Vickers hardness tester. All specimens underwent in-office bleaching with 35% hydrogen peroxide. Group 1 received no remineralizing agent, Group 2 was treated with FluoroDip Bioactive varnish, Group 3 with Ultra EZ gel, and Group 4 with Dente 91 toothpaste. After treatment, specimens were stored in distilled water for 14 days, following which post-treatment microhardness was measured. Statistical analysis was performed using appropriate tests with significance set at p<0.05. Results: Baseline microhardness values showed no statistically significant differences among groups (p=0.32). Post-treatment results demonstrated a significant difference between groups (p<0.001). Group 1 showed a significant reduction in enamel microhardness. Group 2 showed minimal recovery, while Groups 3 and 4 demonstrated significant increases in microhardness, with Dente 91 exhibiting the highest values. Conclusion: In-office bleaching with 35% hydrogen peroxide significantly reduces enamel microhardness. Post-bleaching application of remineralizing agents improves enamel hardness, with Dente 91 showing superior remineralization, followed by Ultra EZ and FluoroDip Bioactive