Effects of neutralizing or antioxidant agents on the consequences induced by enamel bleaching agents in immediate resin composite restorations

• Published in: Journal of adhesion science and technology Vol. 31; no. 9; pp. 965 - 976
• Main Authors: Svizero, Nádia da Rocha, Romani, Luciana Aparecida Calegari, Soares, Idiane Bianca Lima, Moraes, Jéssica Eleotério, Agulhari, Maria Angélica Silvério, Hipólito, Vinicius Di, Sauro, Salvatore, D'Alpino, Paulo Henrique Perlatti
• Format: Journal Article
• Language: English
• Published: Utrecht Taylor & Francis 03-05-2017; Taylor & Francis Ltd
• Subjects: Adhesive bonding; Antioxidants; Bleaching; Dental enamel; Enamels; Failure; Neutralizing; Restoration; shear strength; Sodium; sodium bicarbonate; tooth bleaching
• ISSN: 0169-4243; 1568-5616
• DOI: 10.1080/01694243.2016.1238123

Purpose: Bleaching agents are claimed to impair the bonding to the tooth structure when resin composite restorations are immediately performed. This study aimed to evaluate the effect of a neutralizing solution (10% sodium bicarbonate) or an antioxidant agent (10% sodium ascorbate) on the immediate or delayed (15 days) shear bond strength (SBS) of composite restorations performed on enamel. Seventy flat buccal enamel surfaces obtained from bovine incisors were divided into seven groups (n = 10): control group, unbleached enamel, restored (3M ESPE/Adper Single Bond 2/Filtek Z350XT) (G1); bleached, immediately restored (G2); bleached, delayed restoration (G3); bleached, antioxidant (sodium ascorbate), immediately restored (G4); bleached, antioxidant, delayed restoration (G5); bleached, neutralizing (sodium bicarbonate), immediate restoration (G6); bleached, neutralizing, delayed restoration (G7). Specimens were submitted to SBS test and examined after failure using scanning electron microscopy (SEM). Results were statistically analyzed with ANOVA/Tukey's tests (5%). Bonding to enamel immediately restored after bleaching (G2) was significantly lower than G1 (unbleached enamel; p < 0.05). Applying the antioxidant or neutralizing agent significantly improved the bonding to enamel compared with G2 (bleached, immediate restored), irrespective of the restoration time (immediate or delayed) (p < 0.05). No significance was found between the two agents when applied after bleaching, and compared with the control group, regardless of evaluation time (p > 0.05). SEM images demonstrated adhesive failures in the bleached, immediately restored group (G2). G3-G7 exhibited majority of cohesive and mixed failure patterns. 10% sodium bicarbonate or 10% sodium ascorbate neutralizes the negative immediate and delayed effects of bleaching on bond strength of enamel bleached enamel.