title: Metal ion release from silver soldering and laser welding caused by different types of mouthwash.
abstract: OBJECTIVE
  To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients.
  
  
  METHODS
  A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons.
  
  
  RESULTS
  The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings.
  
  
  CONCLUSIONS
  The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.
authors.affiliation: a  Research Assistant, Department of Orthodontics, Yeditepe University Faculty of Dentistry, Istanbul, Turkey.
authors.forename: Ayse Tuygun
authors.initials: AT
authors.lastname: Erdogan
authors.affiliation: b  Associate Professor, Department of Orthodontics, Yeditepe University Faculty of Dentistry, Istanbul, Turkey.
authors.forename: Didem
authors.initials: D
authors.lastname: Nalbantgil
authors.affiliation: c  Assistant Professor, Department of Orthodontics, Yeditepe University Faculty of Dentistry, Istanbul, Turkey.
authors.forename: Feyza
authors.initials: F
authors.lastname: Ulkur
authors.affiliation: d  Professor, Department of Genetics and Bioengineering, Yeditepe University Faculty of Engineering and Architecture, Istanbul, Turkey.
authors.forename: Fikrettin
authors.initials: F
authors.lastname: Sahin
mesh_terms: D002710:Chlorhexidine / Q000737:chemistry; D002857:Chromium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D012994:Dental Soldering / Q000295:instrumentation / Q000379:methods*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D007477:Ions; D007501:Iron / Q000737:chemistry; D007834:Lasers; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009067:Mouthwashes / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry; D009967:Orthodontic Appliances; D012464:Saliva, Artificial / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D012969:Sodium Fluoride / Q000737:chemistry; D013054:Spectrophotometry, Atomic / Q000379:methods; D013997:Time Factors; D015032:Zinc / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D007477:Ions; D008670:Metals; D009067:Mouthwashes; D012464:Saliva, Artificial; D002857:Chromium; D000431:Ethanol; D012834:Silver; D003300:Copper; D009532:Nickel; D012969:Sodium Fluoride; D007501:Iron; D015032:Zinc; D002710:Chlorhexidine
keywords: Corrosion; Ion release; Laser welding; Mouthwashes; Silver soldering