title: [Comparison of the difference of the magnetic force by cast post-keepers combined with three different metals].
abstract: OBJECTIVE
  Three different metals were used to make cast post-keepers of magnetic attachment. The magnetic force was tested and analyzed.
  
  
  METHODS
  The cast-post keepers were combined by gold alloy, Ni-Cr alloy and Ti metal respectively. 12 samples were divided into three groups, 4 in each. Root surface structures were manufactured by these samples. The values of the magnetic force of the magnetic attachment were tested and compared using ANOVA.
  
  
  RESULTS
  The average value of the attractive force of the keeper combined by gold alloy was 4.84N, while that of the keeper combined by Ni-Cr alloy was 4.61N and the keeper combined by Ti was 4.12N. Significant difference was found between each two samples, P<0.01.
  
  
  CONCLUSIONS
  The magnetic force of the keepers combined by three different metals decreased to certain degrees, the keeper combined by gold alloy decreased the least.
authors.affiliation: Department of Prosthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Bin
authors.initials: B
authors.lastname: Wei
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D060328:Magnetic Phenomena; D008670:Metals; D014025:Titanium / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D006047:Gold Alloys; D008670:Metals; D014025:Titanium