title: [A comparison between the cast-bonded keeper with different dental alloys in the metallographic structure].
abstract: OBJECTIVE
  The aim of this study is to investigate the changes of the metallographic structure of the cast-bonded keeper when cast in varied temperatures.
  
  
  METHODS
  Three groups were included in this study: the gold alloy group, the Ni-Cr alloy group and Ti group, with the Magdisc 500 keeper as the control group. Each sample that contained a Magdisc 500 keeper was fabricated with the cast-bonded technique. Then, the samples were fabricated into a metallographic sample by polishing, smoothing and cleaning. Each sample was observed under metallographic microscope.
  
  
  RESULTS
  There were no significant changes in the crystal size between the keeper in the gold alloy group and that in the control group. In both of the Ni-Cr alloy group and Ti group, the crystal of the keeper became larger, and this was more evident in the latter group.
  
  
  CONCLUSIONS
  The keeper varied in the metallographic structure if cast-bonded with gold alloy, Ni-Cr alloy or Ti metal. The higher the casting temperature, the larger the crystal of the keeper. The results suggest that the change in the gold group is less than that in the Ni-Cr alloy group and Ti metal group.
authors.affiliation: Department of Prosthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China. zhengyuanli@yahoo.com
authors.forename: Yuan-li
authors.initials: YL
authors.lastname: Zheng
authors.forename: Bing
authors.initials: B
authors.lastname: Wei
authors.forename: Han-xi
authors.initials: HX
authors.lastname: Yao
mesh_terms: D002858:Chromium Alloys; D003722:Dental Alloys; D003735:Dental Casting Technique; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D006047:Gold Alloys; D008422:Materials Testing; D014025:Titanium
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D006047:Gold Alloys; D014025:Titanium