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Effects of Overnight Whitening Pens on Hydrogen Peroxide Penetration, Color Change, and Enamel Surface Properties
Iara María Ersilia Lima De León1,2, Laryssa Mylenna Madruga Barbosa1, Gabrielle Gomes Centenaro1
1Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, Paraná, Brazil.
Objective:
To evaluate hydrogen peroxide (HP) permeability into the pulp chamber, objective color change, and enamel surface morphology after overnight use of over-the-counter (OTC) whitening pens.
Materials And Methods:
Fifty sound premolars were assigned to five groups (n = 10): control, Optic White Pen LED (OW), Colgate Luminous White Whitening Pen (LW), Equate Teeth Whitening Kit (EQ), and Whiteness Perfect 10% (WP). Fifteen molars were used for enamel surface analyses (microhardness and roughness). Products were applied for 8 h/day for 10 days. HP penetration (μg/mL) and color change (ΔEab, ΔE00, and WID) were measured by spectrophotometer. Initial HP concentration and pH were determined by titration and pH meter. Data were analyzed using ANOVA (α = 0.05).
Results:
EQ showed the highest HP concentration and the lowest pH. HP penetration was significantly higher for EQ and lowest for WP (p < 0.05). No significant differences in ΔEab and ΔE00 were observed among products, while WID increased over time in all groups. Enamel surface changes were similar, except for EQ, which showed reduced microhardness (p < 0.05).
Conclusions:
Overnight OTC whitening pens showed comparable cumulative bleaching efficacy. However, EQ resulted in greater pulpal HP penetration and enamel softening.
Clinical Significance:
Prolonged overnight OTC whitening pen use may increase pulpal exposure and enamel softening risk, reinforcing cautious use and professional supervision.
