Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 22 0 2025 05 07 4488 4488 Abolfazl Bazari Jamkhaneh Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Zohreh Moradi . Restorative dentistry Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 3. Laser research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran Sina Sadeghabadi Private practice, Tehran, Iran Pooya Soltanzadeh Loma Linda University, School of Dentistry, Loma Linda, California Nasim Chiniforush 6. Dentofacial Deformities Research Center, Research Institute for Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran 7. Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy 2022 05 29 2023 09 12 Objectives: The aim of this study was to assess the color change (∆E) of teeth following the use of several bleaching protocols with power bleaching. Materials and Methods: This in vitro study evaluated 50 sound incisors and premolars. After cleaning, the teeth were immersed in a 2g/100mL tea solution for 6 days. The samples were randomly divided into 5 bleaching groups: Snow L [containing 40% hydrogen peroxide (HP) and 20% carbamide peroxide] with 980nm diode laser, White Smile (containing 32% HP) with LED (Monitex), Boost (containing 40% HP) with 980nm diode laser, Boost (containing 40% HP) with LED (Monitex), and Boost without activation. Color parameters were measured before and after staining, immediately and 1 week after bleaching by a spectrophotometer, and their ∆E was calculated and compared by one-way ANOVA followed by the Tukey’s test. Results: All bleaching protocols improved the color parameters. The ∆E in each group was significant after bleaching compared to before bleaching in the cervical (P<0.001), middle (P<0.001) and incisal (P<0.001) thirds. The ∆E was significant at 1 week compared to before bleaching (P=0.002 for the cervical, P<0.001 for the middle, and P<0.001 for the incisal third, respectively), immediately after bleaching compared with after staining (all Ps<0.001), and also at 1 week compared with after staining (all Ps<0.001). Conclusion: Within the study limitations, all power bleaching protocols caused color change of the teeth. The efficacy of Boost (conventional bleaching), Boost plus LED, and White Smile was better than Snow L regarding color change of teeth. https://fid.tums.ac.ir/index.php/fid/article/view/4488 https://fid.tums.ac.ir/index.php/fid/article/download/4488/2144