title: [The measurement of retentive force of laser-melted and cast post-keepers of Magfit magnetic attachments].
abstract: OBJECTIVE
  In order to compare the influence of casting and laser welding on magnetic retentive force, the magnetic retentive forces of laser-melted and cast post-keepers of the magnetic attachments were measured in vitro.
  
  
  METHODS
  5 cast and 6 laser-melted post-keeper specimens (Magfit MD800) were formed, respectively. Using untreated keeper as control group, the vertical magnetic retentive forces were measured by a universal testing machine.
  
  
  RESULTS
  The average vertical magnetic retentive force of the laser-melted post-keeper group and the cast post-keeper group in vitro were (4.223 +/- 0.217,0)N, (3.792,9 +/- 0.296,4)N, respectively. Compared with the cast post-keeper group, the average vertical magnetic retentive force of the laser-melted post-keeper groups was much higher in vitro (P < 0.05).
  
  
  CONCLUSIONS
  Laser welding had less influence on the magnetic retentive force of the magnetic attachments than casting.
authors.affiliation: Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Du
authors.forename: Yinghe
authors.initials: Y
authors.lastname: Lin
mesh_terms: D003722:Dental Alloys; D003734:Dental Casting Investment; D003735:Dental Casting Technique; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D012994:Dental Soldering / Q000379:methods*; D003834:Denture Precision Attachment; D004574:Electromagnetic Fields; D007834:Lasers; D008280:Magnetics / Q000295:instrumentation*; D011176:Post and Core Technique; D013193:Stainless Steel; D014896:Welding / Q000379:methods
chemical_list: D003722:Dental Alloys; D003734:Dental Casting Investment; D013193:Stainless Steel