title: Recycling stainless steel orthodontic brackets with Er:YAG laser - An environmental scanning electron microscope and shear bond strength study.
abstract: OBJECTIVE
  TO DETERMINE THE EFFICIENCY OF ERBIUM: Yttrium aluminum garnet (Er:YAG) laser with Environmental Scanning Electron Microscope (ESEM) and shear bond strength analysis as a method of recycling stainless steel orthodontic brackets and compare with other methods of recycling.
  
  
  METHODS
  Eighty samples of extracted premolar teeth bonded to SS brackets were tested for rebonded shear bond strength after recycling by four methods and compared with a control group of 20 samples. These 80 samples were randomized into four groups which were recycled by four methods, namely, sandblasting, thermal method, adhesive grinding by tungsten carbide bur, and Er: YAG laser method. After recycling, ESEM and shear bond strength analysis were used to analyze the efficiency of the recycling methods.
  
  
  RESULTS
  ER: YAG laser group was found to be having the greatest bond strength among the recycled brackets (8.33±2.51 followed by the sandblasting at 6.12±1.12 MPa, thermal and electropolishing at 4.44±0.95 MPa, and lastly the adhesive grinding method at 3.08±1.07 MPa. The shear bond strength of Er: YAG laser group was found to be having no statistically significant difference with that of the control group (P>0.05 and had statistical signifance with sandblasting, thermal and electropolishing and adhesive grinding groups at P>0.001. ESEM analysis showed complete removal of adhesive from the brackets recycled with Er: YAG laser which mimicked that of the control group.
  
  
  CONCLUSIONS
  ER: YAG laser (2940 nm) was found to be the most efficient method for recycling, followed by the sandblasting, thermal, and the tungsten carbide methods, which had the least shear bond strength value and is not fit for clinical usage.
authors.affiliation: Department of Orthodontics, KVG Dental College and Hospital, Sullia, India.
authors.forename: Prince K
authors.initials: PK
authors.lastname: Chacko
authors.affiliation: Department of Orthodontics, KVG Dental College and Hospital, Sullia, India.
authors.forename: Jithesh
authors.initials: J
authors.lastname: Kodoth
authors.affiliation: Department of Orthodontics, KVG Dental College and Hospital, Sullia, India.
authors.forename: Jacob
authors.initials: J
authors.lastname: John
authors.affiliation: Department of Orthodontics, AJ Shetty Dental College and Hospital, Mangalore, Dakshin Kannada, Karnataka, India.
authors.forename: Kishore
authors.initials: K
authors.lastname: Kumar
keywords: Bond strength; environmental scanning electron microscope; erbium: yttrium aluminum garnet laser; orthodontic brackets; recycling