title: [An experimental study on the adaptation of three kinds of porcelain fused-to-metal restorations].
abstract: OBJECTIVE
  To compare the adaptation of porcelain fused-to-metal (PFM) restorations made from Ni-Cr alloy, precious alloy and galvanized forming copings after cementation and to provide a theory guidance for their application.
  
  
  METHODS
  Three kinds of crowns (Ni-Cr alloy, precious alloy and galvanized forming) were manufactured and cleaned by ultrasonic vibrate with alcoholic solution for 5 minutes, and cemented on their dies as their order. All the crowns were cemented by polycarboxylate zinc-cement and maintained 10 minutes. After coated in the center of methyl acrylic resins, all the samples were cut vertically along buccolingual direction. The cement thickness of PFM was measured by scanning electron microscope and the data were analyzed by multivariate ANOVA.
  
  
  RESULTS
  No significant difference was found between the cement thickness of precious alloy crown and galvanized forming crown (P>0.05), while both of these two kinds of crown had significant differences in cement thickness with Ni-Cr crown (P<0.05).
  
  
  CONCLUSIONS
  The adaptation of precious alloy crown and galvanized forming crown are superior to Ni-Cr crown.
authors.affiliation: Dept. of Stomatology, Navy General Hospital, Beijing 100037, China.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Pei
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Chen
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.forename: Song-Shan
authors.initials: SS
authors.lastname: Lin
authors.forename: He
authors.initials: H
authors.lastname: Zhang
mesh_terms: D002484:Cementation; D003442:Crowns; D003738:Dental Cements; D003776:Dental Porcelain; D005899:Glass Ionomer Cements; D008670:Metals
chemical_list: D003738:Dental Cements; D005899:Glass Ionomer Cements; D008670:Metals; D003776:Dental Porcelain