title: [The influence of the try-in pastes on the colour of all-ceramic veneers].
abstract: OBJECTIVE
  To study the influence of the try-in pastes on the color of all-ceramic veneers made by Ips-empress II system.
  
  
  METHODS
  50 discolored teeth were collected and restored with all-ceramic veneers. Five try-in pastes including A1, A3, transleucent(Trt), white opaque(WOT) and B0.5 opaque(B0.5),which were different in shade, were respectively used to try in before cementing. The color was measured by the ShadeEye, a digital colorimeter, and expressed in terms of 3 coordinate values (L*,a*,b*) of the CIEL*a*b* system. Then the color differences(deltaEa*b*) of all-ceramic veneers[deltaEa*b*=(deltaL*(2)+deltaa*(2)+deltab*(2))(1/2)] as well as the value of L*deltaC(ab)[C(ab)=(a*(2)+b*(2))(1/2)] and H(ab)[H(ab)=arctan(b*/a*)]were calculated. Meanwhile,the thickness of the measurement point was measured and recorded. One-way ANOVA was used to analyze deltaEa*b* as well as L*,C(ab) and Hab.
  
  
  RESULTS
  The average thickness of the ceramic was 1.088mm, and the colour of the veneers after try in with WOT paste and B0.5 paste performed a higher L* value than the other pastes (P<0.05).And the veneers also showed a higher C(ab) value after try in with WOT,B0.5 and A3 paste than the A1 and Trt paste (P<0.05). No significant differences were found in Hab value after these 50 veneers tried in with these five kinds of pastes.
  
  
  CONCLUSIONS
  It's more advisable to choose the WOT or the B0.5 luting agent to cement the veneer when the abutment tooth is severely discolored, while the Trt or the A1 shade and A3 shade luting resin may be more appropriate if the abutment tooth doesn't discolor or a little compared with the adjacent tooth.
authors.affiliation: Department of Prosthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China. xyinzhang@yahoo.com.cn
authors.forename: Xiu-yin
authors.initials: XY
authors.lastname: Zhang
authors.forename: Hai-xin
authors.initials: HX
authors.lastname: Qian
authors.forename: Dan-ling
authors.initials: DL
authors.lastname: Yang
authors.forename: Hong
authors.initials: H
authors.lastname: Gan
authors.forename: Ming
authors.initials: M
authors.lastname: Min
authors.forename: Wei-qiang
authors.initials: WQ
authors.lastname: Yu
mesh_terms: D002516:Ceramics; D003116:Color; D003124:Colorimetry; D003738:Dental Cements; D003776:Dental Porcelain; D003801:Dental Veneers; D006801:Humans; D009824:Ointments
chemical_list: D003738:Dental Cements; D009824:Ointments; D003776:Dental Porcelain