title: [Influence of SiO2 films on color reproduction of Ni-Cr alloy porcelain crowns].
abstract: OBJECTIVE
  To study whether SiO2 films will influence the color of Ni-Cr metal ceramic restorations.
  
  
  METHODS
  For the film plating experimental group, Sol-gel method was employed to apply SiO2 films to the surface of the Ni-Cr copings, while no coating was applied for the non-film-plating control group. Veneering porcelains were then applied subsequently, and a total of 12 B2-colored maxillary incisor metal ceramic crowns were fabricated with 6 crowns in each group. A ShadeEye Ncc computer-aided colorimeter was employed to measure the shade of the samples, as well as 6 B2(Vitapan classical vita color tabs) shade standards. The color was expressed as C1E-1976-Lab coordinates.
  
  
  RESULTS
  There was a statistically significant color difference between all metal ceramic crowns and the B2 shade standards (delta E>1.5). The L*, a*, b* values of all crowns were higher than those of the B2 shade standards, and the crowns were typically yellower or redder. While neither significant color difference nor difference in shade values was observed between the film plating experimental group and non-film-plating control group (delta E<1.5).
  
  
  CONCLUSIONS
  SiO2 films applied to the Ni-Cr copings by means of Sol-gel technique do not impact the final color of the metal ceramic restorations.
authors.affiliation: Dept. of Stomatology, The Second Xiangya Hospital, Central South University, Changsha 410011, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wu
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000497:Alloys; D003116:Color; D003124:Colorimetry; D003442:Crowns; D003776:Dental Porcelain; D007180:Incisor; D016876:Metal Ceramic Alloys; D017797:Prosthesis Coloring; D012822:Silicon Dioxide
chemical_list: D000497:Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D012822:Silicon Dioxide