title: Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets.
abstract: OBJECTIVE
  The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets.
  
  
  METHODS
  3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy.
  
  
  RESULTS
  Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p < 0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket.
  
  
  CONCLUSIONS
  Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.
authors.affiliation: Department of Orthodontics, Capital Medical University School of Stomatology, Dongcheng District, Beijing 100050, China.
authors.forename: Ruo-qiao
authors.initials: RQ
authors.lastname: Han
authors.affiliation: Department of Orthodontics, Capital Medical University School of Stomatology, Dongcheng District, Beijing 100050, China.
authors.forename: Kai
authors.identifier: 0000-0003-0118-9370
authors.initials: K
authors.lastname: Yang
authors.affiliation: Institute of Laser Engineering, Beijing University of Technology, Chaoyang District, Beijing 100124, China.
authors.forename: Ling-fei
authors.initials: LF
authors.lastname: Ji
authors.affiliation: Institute of Laser Engineering, Beijing University of Technology, Chaoyang District, Beijing 100124, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Ling
mesh_terms: D001641:Bicuspid / Q000502:physiology; D002516:Ceramics / Q000737:chemistry* / Q000528:radiation effects; D003738:Dental Cements; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D016910:Orthodontic Brackets; D033081:Shear Strength; D013059:Spectrum Analysis, Raman
chemical_list: D003738:Dental Cements