Objectives: This study investigated the effects of three over-the-counter (OTC) whitening products, whitening pen (WP, Dazzling White Instant Whitening Pen, Dazzling White, Grand Rapids, MI, USA), whitening mouthwash (MW, Colgate Optic White, Colgate-Palmolive, New York, NY, USA), and whitening toothpaste (TP, Crest 3D White, Procter p < 0.001), with the greatest reduction observed in the MW group. Gloss retention also declined significantly (MD 95% CI: 9.52 6.28–12.76 for WP, 17.97 14.92–21.01 for MW, and 18.92 15.64–22.21 for TP; p < 0.001), with TP and MW showing greater loss compared to WP. Surface roughness increased significantly within each group (MD 95% CI: −0.07 –0.10 to −0.04 for WP, −0.23 –0.30 to −0.16 for MW, and −0.25 –0.38 to −0.13 for TP; p < 0.001), although no significant differences were found among groups in post-treatment values. Conclusions: OTC whitening products adversely affected the optical and mechanical properties of Z350 XT universal composite resin. Whitening MW caused the most pronounced microhardness reduction, while MW and TP induced greater gloss loss than WP. Clinicians should consider the potential impact of whitening products on resin composite restorations when advising patients on their use.
Binhasan et al. (Thu,) studied this question.