title: The Use of the Er:YAG Laser for Bracket Debonding and Its Effect on Enamel Damage.
abstract: OBJECTIVE
  The aim of the study was to evaluate the influence of Er:YAG laser irradiation on the debonding of metal and ceramic brackets and enamel damage ex vivo.
  
  
  BACKGROUND
  The principle of safe bracket debonding is to degrade the adhesive resin strength connecting the tooth and bracket. Removal of adhesive resin from tooth surfaces without iatrogenic damage (enamel loss) is generally the main problem of the otherwise very successful method of aesthetic straightening of teeth.
  
  
  METHODS
  Forty ceramic and metal brackets (Clarity™ Advanced and Victory Series™; 3M Unitek, Monrovia, CA) were standardly bonded to buccal polished enamel surfaces of 30 caries-free human third molars. Two types of adhesive resins (Transbond™ XT Light Cure Adhesive; 3M Unitek, and Variolink II Professional Set; Ivoclar Vivadent AG) were used. Before debonding, the brackets in the laser group were irradiated with the Er:YAG laser (FJFI CVUT) 280 mJ, 250 μs long, repetition rate 6 Hz, spot focus 1 mm, and 140 sec. The control group was debonded without the laser irradiation. During the bracket irradiation, temperature changes inside the tooth were monitored using a thermal image infrared camera. The enamel surface was investigated by SEM.
  
  
  RESULTS
  It has been observed that bracket removal was easier after the Er:YAG laser irradiation, and temperature rise was limited (from 2.0°C to 3.2°C) also for metal brackets. As against the nonirradiated samples, SEM investigation has confirmed no damage to enamel.
  
  
  CONCLUSIONS
  Irradiation with Er:YAG laser radiation before debonding of ceramic brackets significantly decreases the bonding failure and amount of remaining adhesive.
authors.affiliation: 1 Department of Stomatology, 2nd Medical Faculty and FN Motol, Charles University , Prague, Czech Republic .
authors.forename: Tatjana
authors.initials: T
authors.lastname: Dostalova
authors.affiliation: 2 Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague , Prague, Czech Republic .
authors.forename: Helena
authors.initials: H
authors.lastname: Jelinkova
authors.affiliation: 1 Department of Stomatology, 2nd Medical Faculty and FN Motol, Charles University , Prague, Czech Republic .
authors.forename: Marek
authors.initials: M
authors.lastname: Remes
authors.affiliation: 2 Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague , Prague, Czech Republic .
authors.forename: Jan
authors.initials: J
authors.lastname: Šulc
authors.affiliation: 2 Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague , Prague, Czech Republic .
authors.forename: Michal
authors.initials: M
authors.lastname: Němec
mesh_terms: D000293:Adolescent; D000328:Adult; D017005:Dental Debonding / Q000295:instrumentation*; D003743:Dental Enamel / Q000293:injuries* / Q000528:radiation effects*; D006801:Humans; D066298:In Vitro Techniques; D053844:Lasers, Solid-State; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D016910:Orthodontic Brackets; D013499:Surface Properties