To evaluate the laboratory effects of different whitening toothpastes on human anterior teeth that had undergone in-office bleaching with a 40% hydrogen peroxide (HP) agent.Fifty caries-free human anterior teeth extracted for periodontal or orthodontic reasons were randomly assigned to five groups (n=10): Group 1 (Control) : Bleached but no toothpaste applied; Group 2: Ipana Kalsident Classic Taste toothpaste; Group 3: Colgate Optic White Expert toothpaste; Group 4: Signal White Now Gold toothpaste; Group 5: Opalescence Whitening toothpaste. Baseline and post-bleaching color measurements were performed using a digital spectrophotometer. Following bleaching with 40% HP (Opalescence Boost 40% PF), the control group was brushed with distilled water, while the experimental groups were brushed with the respective toothpastes twice daily for 30 days using a rechargeable toothbrush. Final color measurements were recorded, and color changes (ΔE₀₀) were calculated using the CIE2000 formula. Data were analyzed using ANOVA and Tukey tests (P= 0.05).The use of whitening toothpastes after bleaching significantly enhanced tooth color. Opalescence Whitening exhibited the greatest effect, followed by Colgate Optic White Expert. Signal White Now Gold demonstrated significantly higher efficacy than Ipana Kalsident Classic Taste. However, no significant difference was observed between the control group and Ipana.This study demonstrated that whitening toothpastes play a beneficial role in maintaining and enhancing tooth color following in-office bleaching. Clinically, the use of an appropriate whitening toothpaste is recommended to prolong and optimize the results of bleaching procedures.