title: Shear bond strength and morphological analysis of KrF laser-recycled metal brackets.
abstract: OBJECTIVE
  The aim of this study was to compare the effect of a KrF excimer laser versus traditional chairside deboned bracket processing methods of grinding, flaming, and sandblasting on the shear bond strength and morphological change of recycled brackets.
  
  
  BACKGROUND
  Bracket dislodgement happens frequently in orthodontic treatment.
  
  
  METHODS
  The Victory Series bracket with a foil-mesh base and the Mini Sprint bracket with a raised base were chosen in this research. Grind, flame, sandblast, and laser groups acted as the experimental groups, and the new bracket group served as control. The shear bond strengths were determined with an Electroforce test machine and statistically tested by an analysis of variance (ANOVA). Morphological examinations of the recycled bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Bracket base residue content was analyzed using Raman spectroscopy.
  
  
  RESULTS
  The study showed that adhesive was left on the recycled bracket base processed by grinding and flaming, with significantly decreased shear bond strength (p<0.05). Sandblasting and KrF excimer lasering both thoroughly removed the adhesive. Shear bond strength decreased with sandblasting in the Victory bracket but not in the Mini Sprint bracket. Shear bond strength of KrF-lasered recycled brackets did not differ statistically from that of both kinds of new brackets. The study also showed that KrF excimer laser caused limited damage to the bracket.
  
  
  CONCLUSIONS
  The KrF excimer laser can remove adhesive on the two different bracket bases effectively, causing little damage to the bracket; therefore, it is a superior bracket refurbishing method worth further study.
authors.affiliation: 1 Department of Orthodontics, Capital Medical University School of Stomatology , Dongcheng District, Beijing, P. R. China .
authors.forename: Lili
authors.initials: L
authors.lastname: Shi
authors.forename: Kai
authors.initials: K
authors.lastname: Yang
authors.forename: Lingfei
authors.initials: L
authors.lastname: Ji
authors.forename: Chen
authors.initials: C
authors.lastname: Ling
mesh_terms: D001840:Dental Bonding; D007834:Lasers; D008670:Metals; D016910:Orthodontic Brackets; D059027:Recycling; D033081:Shear Strength
chemical_list: D008670:Metals