title: The fatigue life of a cobalt-chromium alloy after laser welding.
abstract: The aim of this study was to investigate the fatigue life of laser welded joints in a commercially available cast cobalt-chromium alloy. Twenty rod shaped specimens (40 mm x 1.5 mm) were cast and sand blasted. Ten specimens were used as controls and the remaining ten were sectioned and repaired using a pulsed Nd: YAG laser welder. All specimens were subjected to fatigue testing (30N - 2Hz) in a controlled environment. A statistically significant difference in median fatigue life was found between as-cast and laser welded specimens (p < 0.001). Consequently, the technique may not be appropriate for repairing cobalt chromium clasps on removable partial dentures. Scanning electron microscopy indicated the presence of cracks, pores and constriction of the outer surface in the welded specimens despite 70% penetration of the weld.
authors.affiliation: Department of Restorative Dentistry, Guys Hospital, London, United Kingdom.
authors.forename: Nabil Jalal Ahmad
authors.initials: NJ
authors.lastname: Al-Bayaa
authors.forename: Robert K F
authors.initials: RK
authors.lastname: Clark
authors.forename: Andrzej S
authors.initials: AS
authors.lastname: Juszczyk
authors.forename: David R
authors.initials: DR
authors.lastname: Radford
mesh_terms: D002858:Chromium Alloys; D003035:Cobalt; D003799:Dental Stress Analysis; D003780:Denture Repair; D003832:Denture, Partial, Removable; D053844:Lasers, Solid-State; D008422:Materials Testing; D013314:Stress, Mechanical; D013718:Tensile Strength; D014896:Welding / Q000379:methods*
chemical_list: D002858:Chromium Alloys; D003035:Cobalt