High‐Concentration Hydrogen Peroxide Gels Containing Calcium Polyphosphate Associated With Violet Led Light: Bleaching Efficacy and Effects on Enamel Properties

ABSTRACT Objectives To evaluate the effect of violet LED light (VL) and hydrogen peroxide (HP) in‐office bleaching gels supplemented with calcium polyphosphate (CaPP) or calcium gluconate (GU): Materials and Methods Bovine enamel blocks ( n = 10) were randomly assigned: commercial HP gel, commercial HP gel with GU, or experimental 35% HP with or without CaPP (0.5 or 1.5 wt%), and their VL‐irradiated versions. Bleaching efficacy was assessed by color analyses (CIE L*a*b*, Δ E ab , Δ E 00 , Δ WID ) at baseline ( T 0 ) and after treatment ( T 1 ). Knoop microhardness (KHN), percentage surface microhardness loss (%SHL), and roughness variation (ΔRa) were measured at T 0 , T 1 , and 14 days post‐treatment ( T 2 ). Surface morphology was assessed by scanning electron microscopy (SEM). Data were analyzed using generalized linear models, Kruskal–Wallis and Dunn tests ( α = 0.05). Results The group irradiated only with VL exhibited lower color change ( p < 0.0001). CaPP addition significantly increased Δ E 00 in VL‐irradiated groups ( p < 0.05). For roughness and SEM, no significant differences were observed among groups. Only CaPP‐ and GU‐containing gels restored initial KHN values at T 2 ( p < 0.05). CaPP groups showed lower %SHL than control groups ( p < 0.05). Conclusions Bleaching gels containing CaPP maintained bleaching efficacy and mediated enamel microhardness recovery. VL further enhanced the bleaching effect in CaPP gels. Clinical Significance CaPP represents a promising alternative for bleaching gel formulations, promoting enamel remineralization and enhancing bleaching efficacy when combined with VL.