title: [The effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental casting alloys after electrochemical corrosion].
abstract: OBJECTIVE
  To investigate the effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental alloys after electrochemical corrosion.
  
  
  METHODS
  The surface morphology and surface structure of nickel-chromium dental alloys were examined by stereomicroscope and scanning electron microscopy before and after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva. The surface element component and chemical states of nickel-chromium dental alloys were analyzed by X-ray photoelectron spectrograph after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva.
  
  
  RESULTS
  More serious corrosion happened on the surface of nickel-chromium alloy in 1.0 g/L EGCG artificial saliva than in 0 g/L EGCG. The diameters of corrosion pits were smaller, and the dendrite structure of the alloy surface was not affected in 0 g/L EGCG. While the diameters of corrosion pits were larger, the dendritic interval of the alloy surface began to merge, and the dendrite structure was fuzzy in 1.0 g/L EGCG. In addition, the O, Ni, Cr, Be, C and Mo elements were detected on the surface of nickel-chromium alloys after sputtered for 120 s in 0 g/L EGCG and 1.0 g/L EGCG artificial saliva after electrochemical corrosion, and the surface oxides were mainly NiO and Cr(2)O(3). Compared with 0 g/L EGCG artificial saliva, the content of O, NiO and Cr(2)O(3) were lower in 1.0 g/L EGCG.
  
  
  CONCLUSIONS
  The results of surface morphology and the corrosion products both show that the corrosion resistance of nickel-chromium alloys become worse and the oxide content of corrosion products on the surface reduce in 1.0 g/L EGCG artificial saliva.
authors.affiliation: Department of Prosthodontics, Shanghai Stomatology Disease Center. Shanghai 200001;China.E-mail:g_y_qiao@126.com.
authors.forename: Guang-yan
authors.initials: GY
authors.lastname: Qiao
authors.forename: Li-xia
authors.initials: LX
authors.lastname: Zhang
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Qing-ping
authors.initials: QP
authors.lastname: Shen
authors.forename: Jian-sheng
authors.initials: JS
authors.lastname: Su
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives; D002857:Chromium; D002858:Chromium Alloys; D003343:Corrosion; D003722:Dental Alloys; D009532:Nickel; D012464:Saliva, Artificial; D013499:Surface Properties
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D012464:Saliva, Artificial; D002857:Chromium; C066018:nichrome; D009532:Nickel; D002392:Catechin; C045651:epigallocatechin gallate