AbstractObjectivesThis study aimed to investigate the effect of antioxidant (sodium ascorbate) on tooth sensitivity after two in‐office bleaching techniques (light‐activated and chemical bleaching).Materials and MethodsTen patients aged 18–25 were bleached in four groups according to bleaching materials and/or antioxidant used. Group A: Maxillary right quadrant received light‐activated bleaching with antioxidant. Group B: Maxillary left quadrant received light‐activated bleaching without antioxidant. Group C: Mandibular right quadrant received chemical bleaching without antioxidant. Group D: Mandibular left quadrant received chemical bleaching with antioxidant. The tooth sensitivity was recorded using Numerical Rating Scale (NRS) and Schiff Scale (SS) immediately after treatment, 1 day, 1 week, 2 weeks, and 1 month follow‐up periods.ResultsGroup B exhibited higher sensitivity values than Group A. This difference was statistically significant on the first day after treatment (p = 0.027* in NRS and p = 0.046* in SS). Furthermore, antioxidant incorporation in Group D led to a reduction in teeth sensitivity values compared to Group C. This disparity was highly significant on the first day after treatment (p = 0.001* in NRS and p < 0.001** in SS).ConclusionsThe antioxidant (10% sodium ascorbate) reduces the intensity of tooth sensitivity at the different follow‐up periods, especially after 1 day from bleaching.Clinical SignificanceUsing 10% sodium ascorbate after bleaching is advisable to reduce post‐operative tooth sensitivity.