title: [Effects of different cavosurface margins on color matching of the resin composite].
abstract: OBJECTIVE
  To evaluate effects of color matching of different cavosurface margins on the resin composites in vitro.
  
  
  METHODS
  Twenty extracted human premolars with an A2 shade buccal surface were used in this study. Rectangular shaped cavities (3.0 mm depth, 2.0 mm width, 2.0 mm length) were prepared in the center of the buccal surfaces. The gingival and occlusal cavosurface margins were prepared to be either shoulder or bevel; the other cavosurface margins remained vertical. Ten teeth were filled with Clearfil AP-X (AP), the other ten with Clearfil Majesty (MJ) and light cured. The color difference at the cavosurface margin area was measured using a spectrophotometer (CrystalEye) and evaluated by 3 observers subjectively. The data were statistically analyzed using repeated measures ANOVA and Chi-square test.
  
  
  RESULTS
  When measured by CrystalEye, the color difference between the tooth and resin composite was reduced from the center of restoration to the cavosurface margin area. Both objective and subjective evaluations showed that for AP, the color difference at the cavosurface margin area had no statistical difference among 3 types of the margins; for MJ, the color difference at bevel margin area was significantly smaller than that at the vertical margin area.
  
  
  CONCLUSIONS
  The resin composite restorations produced the color matching at marginal area. The color matching of resin composites with higher diffused light transmission property is more susceptible to the type of cavosurface margins. Preparing bevels may reduce the color difference between the restoration and tooth surface.
authors: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Xue
authors: X
authors: Cai
authors: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Jie
authors: J
authors: Nie
authors: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Zu-hua
authors: ZH
authors: Wang
authors: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Hong-yan
authors: HY
authors: Tian
authors: Department of Conservative Dentistry, Beijing Chongwen Hospital of Stomatology, Beijing 100062, China.
authors: Ying
authors: Y
authors: Zhao
authors: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Xiao-yan
authors: XY
authors: Wang
mesh_terms: D001641:Bicuspid; D003116:Color; D003188:Composite Resins; D003737:Dental Cavity Preparation; D003793:Dental Restoration, Permanent; D006801:Humans; D008027:Light; D008689:Methacrylates
chemical_list: C112828:Clearfil AP-X; D003188:Composite Resins; D008689:Methacrylates; C541508:clearfil majesty