title: Intrapulpal Temperature Increase During Er:YAG Laser-Aided Debonding of Ceramic Brackets.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the temperature changes in the pulp chamber while using a newly introduced application of Er:YAG laser to debond ceramic brackets in a study model with a pulpal circulation with and without thermocycled samples.
  
  
  BACKGROUND
  An esthetic alternative to stainless steel brackets, ceramic brackets have been proposed. However, because of their low fracture resistance and high bond strengths, ceramic brackets can cause a problem when they are being removed using conventional techniques.
  
  
  METHODS
  Experimental Groups A and B were established for samples with or without thermocycling. The same 20 maxillary central incisor and 20 premolar teeth were used in both groups. Pulpal blood microcirculation was simulated using an apparatus described in a previous study. Monocrystalline brackets were bonded by using Transbond XT. In Group A, brackets were debonded using the Er:YAG laser (600 mJ, 2 Hz, long pulse, and no air or water spray) after being stored in distilled water for 24 h. In Group B, brackets were debonded using the same laser system as that used in Group A after being stored in distilled water for 24 h and then thermocycled for a total of 5000 cycles between 5°C and 55°C. The laser irradiation duration and intrapulpal temperature changes were measured.
  
  
  RESULTS
  In Group B, the intrapulpal temperature increase of the central incisors was significantly higher than that of the premolar teeth. In the central incisor and premolar teeth groups, there were no statistically significant difference between Groups A and B (p > 0.05). A positive correlation was found between laser irradiation duration and temperature increase (p < 0.01).
  
  
  CONCLUSIONS
  The use of Er:YAG laser is an effective method for debonding the monocrystalline ceramic brackets. This method can be used safely under the consideration of intrapulpal temperature changes.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Bezmialem Vakif University , Istanbul, Turkey .
authors.forename: Hilal
authors.initials: H
authors.lastname: Yilanci
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Bezmialem Vakif University , Istanbul, Turkey .
authors.forename: Zeynep Beyza
authors.initials: ZB
authors.lastname: Yildirim
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Bezmialem Vakif University , Istanbul, Turkey .
authors.forename: Sabri Ilhan
authors.initials: SI
authors.lastname: Ramoglu
mesh_terms: D016001:Confidence Intervals; D017005:Dental Debonding / Q000379:methods; D003782:Dental Pulp / Q000528:radiation effects; D006358:Hot Temperature; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor / Q000528:radiation effects*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000379:methods*; D016910:Orthodontic Brackets; D012307:Risk Factors; D014081:Tooth Extraction
keywords: Er:YAG; dentistry; enamel; laser ablation; lasers; lasers in dentistry