title: Effects of antioxidants on the microleakage of composite resin restorations after external tooth bleaching.
abstract: OBJECTIVE
  To compare the effects of three antioxidants (sodium ascorbate, sodium ascorbate combined with a surfactant, and catalase) on the microleakage of composite resin restorations after external tooth bleaching with 10% carbamide peroxide.
  
  
  METHODS
  Buccal cavities were prepared on the surface of 60 intact premolars, which were randomly divided into six groups. All cavities were filled with composite resin. In group 1, teeth were not bleached; in group 2, cavities were filled immediately after bleaching; in group 3, cavities were delay-filled for 3 weeks; in group 4, cavities were treated with sodium ascorbate after bleaching and then filled; in group 5, cavities were treated with sodium ascorbate combined with surfactant after bleaching and then filled; and in group 6, cavities were treated with catalase after bleaching and then filled. Microleakage of the restorations was measured from sections using a stereomicroscope.
  
  
  RESULTS
  Group 1 displayed the least amount of microleakage, while group 2 showed the greatest amount of microleakage (P < 0.05). Groups 3 and 4 were similar to group 2 (P > 0.05). However, groups 5 and 6 showed a significantly lower amount of microleakage compared to group 2 (P < 0.05).
  
  
  CONCLUSIONS
  Microleakage increased significantly after external bleaching with 10% carbamide peroxide, and decreased when the bleached teeth were treated with sodium ascorbate combined with Tween(®) 80, or with catalase. Catalase was more effective in decreasing microleakage, while delayed filling or treatment with sodium ascorbate alone did not effectively decrease the microleakage.
authors: Department of General Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors: Yanyan
authors: Y
authors: Han
authors: Department of General Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors: Sisu
authors: S
authors: Mo
authors: Department of General Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors: Long
authors: L
authors: Jiang
authors: Department of General Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors: Yaqin
authors: Y
authors: Zhu
keywords: Antioxidant; composite resin; external tooth bleaching; microleakage