Reaction kinetics of sodium ascorbate and dental bleaching gel

• Published in: Journal of dentistry Vol. 37; no. 12; pp. 932 - 936
• Main Authors: Freire, Andrea, Souza, Evelise M, de Menezes Caldas, Danilo Biazzetto, Rosa, Edvaldo Antônio Ribeiro, Bordin, Cynthia França Wolanski, de Carvalho, Ricardo Marins, Vieira, Sergio
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-12-2009; Elsevier Limited
• Subjects: Algorithms; Antioxidant; Antioxidants; Antioxidants - chemistry; Ascorbic Acid - chemistry; Bond strength; Dental bleaching; Dentistry; Free radicals; Humans; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Hypotheses; Indicators and Reagents; Iodine; Kinetics; Materials Testing; Oxidants - chemistry; Oxidation-Reduction; Scanning electron microscopy; Sodium; Sodium ascorbate; Studies; Time Factors; Titrimetry; Tooth Bleaching; Hydrogen peroxide; Sodium ascorbate; Dental bleaching; Antioxidant
• ISSN: 0300-5712; 1879-176X
• DOI: 10.1016/j.jdent.2009.07.008

Abstract Objective The aim of this study was to establish the reaction kinetics of 35% hydrogen peroxide and sodium ascorbate and to determine the mass of antioxidant required to neutralize the bleaching gel. Methods The method used to quantify sodium ascorbate was based on the United States Pharmacopeia (1995)26 . Oxidation–reduction titration was used to confirm the concentration of hydrogen peroxide and sodium ascorbate and to determine the reaction kinetics between them. Results The results indicated a direct correlation between the mass of hydrogen peroxide and that of the antioxidant agent. In addition, 5 min of contact was sufficient to neutralize the hydrogen peroxide used. Conclusion This in vitro study showed that the amount of sodium ascorbate required for reduction of hydrogen peroxide is directly related to the concentration of the latter. In addition, the reaction kinetics between oxidant and antioxidant showed that a longer application time for sodium ascorbate does not influence the effectiveness of the reaction and that 5 min is sufficiently long for this antioxidant to exert an antioxidant effect.