Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 17 0 2020 09 08 3256 3256 EN Amir Sadr Haghighi Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad Emami Dental and Periodontal Research Center, Dentistry Faculty, Tabriz University of Medical Sciences, Tabriz, Iran Elaheh Fakhri Dental and Periodontal Research Center, Dentistry Faculty, Tabriz University of Medical Sciences, Tabriz, Iran Yashar Rezaei Department of Dental Biomaterials, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran 2019 08 19 2020 04 01 Objectives: The purpose of this investigation was to evaluate the color alteration of dental enamel following the use of light-cured and chemically cured composites for bonding of metal brackets. Materials and Methods: Sixty extracted human premolars divided into five groups (n=12) were included in this study. Metal brackets were bonded using chemically cured (System 1+ and Unite) and light-cured (Transbond XT and Grengloo) composites. The control group remained untreated. After 72 hours of immersion in a staining solution and 24 hours of photoaging, the brackets were debonded, and adhesive remnants were cleaned using a 12-blade tungsten carbide bur and polished with Sof-Lex discs. The color was assessed at the baseline and after cleaning procedures in accordance with the CIE L*a*b (lightness, red/green, blue/yellow) color system. Statistical analyses were performed using paired sample t-test and one-way analysis of variance (ANOVA). Results: The L*, a*, and b* parameters showed a significant increase in all adhesive groups (P<0.001). The experimental groups showed significant color changes (P<0.05), and the mean ΔE ranged from 2.46 to 3.15 units. No significant difference was found between the ΔE of the adhesive groups (P>0.05). Conclusion: The enamel color change is influenced by bonding and debonding procedures. Chemically cured and light-cured composites have similar effects on dental enamel color alterations. https://fid.tums.ac.ir/index.php/fid/article/view/3256 https://fid.tums.ac.ir/index.php/fid/article/download/3256/1808