title: Effects of soldering and laser welding on bond strength of ceramic to metal.
abstract: BACKGROUND
  Welding or soldering of metal frameworks negatively affects the overall bond strength between the veneering ceramic and metal.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the effect of soldering and laser-welding procedures on the bond strength between ceramic and metal.
  
  
  METHODS
  Thirty Ni-based metal specimens (Wiron 99) (8 × 4 × 4 mm) were fabricated and divided into 3 groups; soldered (S), laser welded (L), and control (untreated cast alloy) (n=10). In S and L specimens, a notch (1 × 1.5 mm) was prepared longitudinally on the surface of each specimen and filled with compatible alloy (Wiron soldering rods and Wiroweld NC, respectively). Vickers hardness measurements were made after polishing the surfaces with a metallographic polishing kit. A veneering ceramic (VITA VMK 95) was vibrated, condensed in a mold, and fired on the metal frameworks. The specimens were sectioned in 2 axes to obtain nontrimmed bar specimens with a bonding area of approximately 1 mm². Forty bars per block were obtained. Each bar was subjected to microtensile bond strength (μTBS) testing with a crosshead speed of 1 mm/min. The μTBS data (MPa) were recorded, and SEM was used for failure analysis of the tested bars. The measurements were statistically analyzed using a 1-way ANOVA and Tamhane tests (α=.05).
  
  
  RESULTS
  The mean differences in μTBS of veneering ceramic to soldered (10.4 ±2.4 MPa) and laser-welded (11.7 ±1.3 MPa) metal surfaces were not significantly different and were significantly lower than that of the cast alloy (25.4 ±3.6 MPa) (P<.05). The mean Vickers hardness of cast alloy was significantly higher (236 ±17 HV) than soldered (114 ±9 HV) and laser-welded groups (129 ±11 HV) (P<.05).
  
  
  CONCLUSIONS
  Soldering and laser welding significantly decreased the μTBS of a veneering ceramic to a base metal alloy.
authors.affiliation: Department of Prosthodontics, School of Dentistry, University of Ege, Izmir, Turkey.
authors.forename: Akin
authors.initials: A
authors.lastname: Aladağ
authors.forename: M Erhan
authors.initials: ME
authors.lastname: Cömlekoğlu
authors.forename: Mine
authors.initials: M
authors.lastname: Dündar
authors.forename: M Ali
authors.initials: MA
authors.lastname: Güngör
authors.forename: Celal
authors.initials: C
authors.lastname: Artunç
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002858:Chromium Alloys / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003775:Dental Polishing / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry*; D012994:Dental Soldering / Q000295:instrumentation / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D055119:Elastic Modulus; D004548:Elasticity; D006244:Hardness; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength
chemical_list: D017554:Carbon Compounds, Inorganic; D002858:Chromium Alloys; D003722:Dental Alloys; D003734:Dental Casting Investment; D016876:Metal Ceramic Alloys; D017655:Silicon Compounds; C080305:Vita VMK 595; D003776:Dental Porcelain; D009532:Nickel; D000537:Aluminum Oxide; C022088:silicon carbide