Effects of alpha-tocopherol on fracture resistance after endodontic treatment, bleaching and restoration

• Published in: Brazilian oral research 2016-01, Vol.30 (1)
• Main Authors: Jordão-Basso, Keren Cristina Fagundes, Kuga, Milton Carlos, Dantas, Andrea Abi Rached, Tonetto, Mateus Rodrigues, Lima, Suellen Nogueira Linhares, Bandéca, Matheus Coêlho
• Format: Article
• Language: English
• Subjects: alpha-Tocopherol - chemistry; Analysis of Variance; Animals; Antioxidants; Ascorbic Acid - chemistry; Cattle; Composite Resins - chemistry; Dental Restoration, Permanent - adverse effects; Dentistry; DENTISTRY, ORAL SURGERY & MEDICINE; Endodontics; Gels; Hydrogen Peroxide - chemistry; Materials Testing; Reproducibility of Results; Time Factors; Tooth Bleaching; Tooth Bleaching - adverse effects; Tooth Bleaching Agents - chemistry; Tooth Fractures - prevention & control; Tooth, Nonvital - drug therapy; Vitamins - chemistry
• ISSN: 1806-8324; 1807-3107; 1807-3107; 1806-8324
• DOI: 10.1590/1807-3107BOR-2016.VOL30.0069

This study evaluated the effects of 10% alphatocopherol on the fracture resistance of endodontically treated teeth subjected to tooth bleaching with hydrogen peroxide and immediately restored with composite resin. Fifty bovine incisors were selected, including 10 sound teeth that constituted the control group (G1 (C)). The remaining 40 teeth, which were endodontically treated, were divided into four groups (n = 10): G2 (CR), consisting of teeth immediately restored with composite resin; G3 (HP + CR), consisting of teeth subjected to tooth bleaching with 38% hydrogen peroxide and immediately restored with composite resin; G4 (HP + SA + CR), which received treatment similar to that used for G3, but with 10% sodium ascorbate gel applied after the bleaching protocol; and G5 (HP + AT + CR), which was similar to G4 but included 10% alphatocopherol gel as an antioxidant. After 24 h, composite restorations were performed, and teeth were subjected to a fracture resistance test at a speed of 0.5 mm/min in an electromechanical testing machine. The axial force was applied with an angle of incidence of 135° relative to the long axis of the root. Data were subjected to ANOVA and Tukey tests (p = 0.05). G1 exhibited the highest fracture resistance (p < 0.05). No significant differences among the other experimental groups were observed. The 10% sodium ascorbate and 10% alphatocopherol gels did not improve the fracture resistance of endodontically treated teeth subjected to bleaching with 38% hydrogen peroxide.