ObjectivesThis study aimed to compare the efficacy of two non vital whitening techniques, In-office and Walking Bleach, using 35% hydrogen peroxide. The primary research question was to determine which technique achieves greater tooth color improvement.Materials and methodsFifty non-vital anterior teeth with discoloration were randomly assigned to either the In-office (n = 25) or Walking Bleach (n = 25) groups. Tooth color was measured using a Vita EasyShade V (R) spectrophotometer and visual scales (Vita Classical and Bleachguide) before treatment, after each bleaching session, and at a one-month follow-up. Delta E00, Whiteness Index (WID), and Shade Guide Unit (Delta SGU) values were calculated. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney tests.ResultsBoth techniques improved tooth color, with final Delta E00 values of 10.08 for In-office and 8.12 for Walking Bleach. WID values were significantly higher in the In-office group, indicating greater whitening efficacy. Significant differences favoring the In-office method were seen after the first bleaching (p = 0.0337), and one-month follow-up (p = 0.0327).ConclusionsBoth the In-office and Walking Bleach techniques effectively improve the color of non-vital teeth, with the In-office method showing slight advantages at certain times. Clinicians can choose either technique based on safety, patient needs, and clinical context to achieve optimal results.Clinical relevanceThis study provides evidence that both bleaching techniques are viable options for non-vital teeth whitening. The findings help clinicians choose the most appropriate technique based on biological safety and patient needs and desired outcomes, with the In-office technique being preferable for faster results.