title: [A preliminary study on the color effect of IPS Empress all-ceramic veneers].
abstract: OBJECTIVE
  To evaluate the opaquing capacity, color compatibility and stability of IPS Empress all-ceramic veneers.
  
  
  METHODS
  A total of 86 IPS Empress all-ceramic veneers were made for 18 patients. The patients were divided into three groups: Group A was tetracycline teeth, 64 veneers for 5 patients; Group B was non-tetracycline teeth, 22 veneers for 13 patients; Group C was 22 natural vital teeth with normal color as control group. Before and after veneers were inserted, ShadeEye NCC was employed to obtain L * a * b * values of each tooth. The values of cemented veneers used as the baseline, the L * a * b * values of each veneer were measured half a year, 1 year, and 2 years after restoration respectively. All L * a * b * values at different evaluation times were analyzed by SPSS 10.0.
  
  
  RESULTS
  Before and after veneers were restored, the L * a * b * values of both Group A and Group B were significantly different, the color difference being 5.01 and 4.15 respectively. The color difference between Group A and selected shade guides was 2.45. Compared with the baseline value, the L * value of Group A significantly decreased 2 years after restoration, but the DeltaE of different evaluation times was not significantly different. The color difference between Group B and Group C was 0.22 and there was no significant color difference after restoration.
  
  
  CONCLUSIONS
  IPS Empress all-ceramic veneers have excellent opaquing capacity, color compatibility and stability to non-tetracycline teeth. To tetracycline teeth IPS Empress all-ceramic veneers have a certain opaquing capacity, but they cannot completely match with shade guides; the L * value is significantly different after restoration and further studies are needed to evaluate its color effect.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Zhi-yong
authors.initials: ZY
authors.lastname: Li
authors.forename: Xiang-rong
authors.initials: XR
authors.lastname: Cheng
authors.forename: Yi-ning
authors.initials: YN
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D003776:Dental Porcelain; D003801:Dental Veneers; D005260:Female; D006801:Humans; D008297:Male; D017797:Prosthesis Coloring; D013752:Tetracycline / Q000009:adverse effects; D014075:Tooth Discoloration / Q000628:therapy
chemical_list: D003776:Dental Porcelain; D013752:Tetracycline