title: Shear bond strength of orthodontic brackets bonded to porcelain following etching with Er:YAG laser versus hydrofluoric acid.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate the shear bond strength of orthodontic brackets bonded to porcelain following etching with erbium-doped yttrium aluminum garnet (Er:YAG) laser compared with 9.6% hydrofluoric acid (HF).
  
  
  METHODS
  A total of 100 porcelain disk samples were divided into four groups, and after removing their glazed layer, the first group was etched with 9.6% HF, and the other three groups were etched with Er:YAG lasers of 1.6, 2, and 3.2 W, respectively. After application of silane on the disk surfaces, central incisor brackets were bonded with composite on the disks. The disks were mounted on an acrylic stand for measuring the shear bond strengths. The shear bond strengths were measured by a testing machine.
  
  
  RESULTS
  The mean shear bond strength in the laser group with power of 1.6 W (7.88 MPa) was more than that of the HF (7.4MPa), 2-W power (7.52 MPa), and 3.2-W power (7.45 MPa) groups, but this difference was not statistically significant. Examination with an electron microscope showed different patterns of etching by HF and laser. Also, etching by laser and HF had not resulted in cracks on the porcelain surface.
  
  
  CONCLUSIONS
  Er:YAG laser can be a suitable method for bonding of orthodontic brackets to porcelain surfaces.
authors: Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. syassaei@yahoo.com
authors: Soghra
authors: S
authors: Yassaei
authors: Farshad
authors: F
authors: Moradi
authors: Hossein
authors: H
authors: Aghili
authors: Mohamad Hosein Lotfi
authors: MH
authors: Kamran
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000538:Aluminum Silicates / Q000737:chemistry / Q000528:radiation effects; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D055117:Curing Lights, Dental; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003776:Dental Porcelain / Q000737:chemistry* / Q000528:radiation effects; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry*; D053844:Lasers, Solid-State; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016910:Orthodontic Brackets; D017680:Potassium Compounds / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D002858:Chromium Alloys; D003188:Composite Resins; D016876:Metal Ceramic Alloys; D017680:Potassium Compounds; D019279:Resin Cements; D012821:Silanes; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; D006858:Hydrofluoric Acid