Objectives: Surface reaction-type pre-reacted glass-ionomer (S-PRG) filler releases six types of ions with a neutralizing ability. This study evaluated the effect of S-PRG filler incorporation in an H2O2-based bleaching material on the bleaching efficacy, pH, and reaction state. Materials and Methods: The experimental bleaching material was formulated by the addition of 5% or 10% S-PRG fillers to the powder part. The stained bovine teeth were treated with the prepared bleaching paste. Commission internationale de l'éclairage (CIE) L*a*b* color space values were recorded before and after bleaching, and the color difference (ΔE) was calculated. Moreover, the used bleaching formulations were assessed for their pH values and reaction state by evaluating the oxidation state of manganese (Mn+2) using electron spin resonance (ESR). Results: Bleaching efficacy was increased by addition of S-PRG filles; no significant difference was observed between groups containing 5% and 10% S-PRG fillers. A significant increase in pH in S-PRG filler groups (5% pH 6.7, 10% pH 6.8) was found compared to the 0 % group (pH 4.8). ESR measurements showed that the signal emitted from Mn+2 decreased over time. The S-PRG filler groups showed a significantly higher reduction in Mn+2 compared to the 0% group, with no significant difference between the 5% and 10% S-PRG groups. Conclusions: S-PRG filler addition resulted in improved bleaching efficacy, higher reaction rate, and pH values that are close to neutral. Clinical Relevance: The effect of S-PRG filler addition may be effective on bleaching of H2O2-based martials.

Objectives: Surface reaction-type pre-reacted glass-ionomer (S-PRG) ller releases six types of ions with a neutralizing ability. This study evaluated the effect of S-PRG ller incorporation in an H 2 O 2 -based bleaching material on the bleaching e cacy, pH, and reaction state.Materials and Methods: The experimental bleaching material was formulated by the addition of 5% or 10% S-PRG llers to the powder part. The stained bovine teeth were treated with the prepared bleaching paste. Commission internationale de l'éclairage (CIE) L*a*b* color space values were recorded before and after bleaching, and the color difference (ΔE) was calculated. Moreover, the used bleaching formulations were assessed for their pH values and reaction state by evaluating the oxidation state of manganese (Mn +2 ) using electron spin resonance (ESR).Results: Bleaching e cacy was increased by addition of S-PRG lles; no signi cant difference was observed between groups containing 5% and 10% S-PRG llers. A signi cant increase in pH in S-PRG ller groups (5% pH 6.7, 10% pH 6.8) was found compared to the 0 % group (pH 4.8). ESR measurements showed that the signal emitted from Mn +2 decreased over time. The S-PRG ller groups showed a signi cantly higher reduction in Mn +2 compared to the 0% group, with no signi cant difference between the 5% and 10% S-PRG groups.Conclusions: S-PRG ller addition resulted in improved bleaching e cacy, higher reaction rate, and pH values that are close to neutral.Clinical Relevance: The effect of S-PRG ller addition may be effective on bleaching of H 2 O 2 -based martials.

In-office bleaching with high concentrations of hydrogen peroxide (H2O2) agents causes undesirable alterations in the enamel. Surface pre-reacted glass-ionomer (S-PRG) filler is a functional material known for its acid-neutralizing and demineralization-inhibition properties. This study evaluates the effect of S-PRG filler incorporation in H2O2-based bleaching on the enamel surface. Bovine enamel surfaces were bleached using a bleaching paste formulated with a liquid (35% H2O2) and a powder containing 5% or 10% S-PRG filler. The surface roughness and the Vickers microhardness of the treated enamel surfaces were evaluated. The enamel surfaces were observed under a scanning electron microscope (SEM) and analyzed using energy dispersive X-ray (EDX) technology. The surfaces were challenged by citric acid and observed by SEM. The specimens bleached with the paste containing the S-PRG filler showed lower enamel surface roughness and higher microhardness values than did those bleached with the plain paste (0% S-PRG filler); meanwhile, there were no significant differences between the 5% or 10% S-PRG filler groups. The S-PRG filler groups showed enamel surface morphologies similar to those of the non-bleached enamel, according to SEM observation, and EDX analysis detected the presence of fluoride and strontium ions. The S-PRG filler groups showed a higher resistance to erosion. The S-PRG filler mitigated the detrimental effects of bleaching agents on the enamel surface and provided resistance to erosion.