title: Temperature rises during application of Er:YAG laser under different primary dentin thicknesses.
abstract: OBJECTIVE
  The present study investigated the effects of the Er:YAG laser's different pulse repetition rates on temperature rise under various primary dentin thicknesses.
  
  
  BACKGROUND
  The Er:YAG laser can be used for restorative approaches in clinics and is used to treat dental caries. There are some reports that explain the temperature rise effect of the Er:YAG laser. Recently, the Er:YAG laser has been found to play an important role in temperature rises during the application on dentin.
  
  
  METHODS
  Caries-free primary mandibular molars were prepared to obtain dentin discs with 0.5, 1, 1.5, and 2 mm thicknesses (n=10). These discs were placed between the Teflon mold cylinders of a temperature test apparatus. We preferred three pulse repetition rates of 10, 15, and 20 Hz with an energy density of 12.7 J/cm2 and a 230 μs pulse duration. All dentin discs were irradiated for 30 sec by the Er:YAG laser. Temperature rises were recorded using an L-type thermocouple and universal data loggers/scanners (E-680, Elimko Co., Turkey). Data were analyzed by two-way ANOVA and Tukey tests.
  
  
  RESULTS
  Whereas the lowest temperature rise (0.44±0.09 °C) was measured from a 10 Hz pulse repetition rate at a dentin thickness of 2 mm, the highest temperature rise (3.86±0.43 °C) was measured from a 20 Hz pulse repetition rate at a 0.5 mm dentin thickness.
  
  
  CONCLUSIONS
  Temperature rise did not reach critical value for pulpal injury in any primary dentin thicknesses irradiated by a high repetition rate of the Er:YAG laser.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey. hubbezoglu@gmail.com
authors.forename: Ihsan
authors.initials: I
authors.lastname: Hubbezoglu
authors.forename: Murat
authors.initials: M
authors.lastname: Unal
authors.forename: Recai
authors.initials: R
authors.lastname: Zan
authors.forename: Feridun
authors.initials: F
authors.lastname: Hurmuzlu
mesh_terms: D001831:Body Temperature / Q000528:radiation effects*; D002648:Child; D003804:Dentin / Q000528:radiation effects*; D005260:Female; D006801:Humans; D053844:Lasers, Solid-State; D008297:Male; D011829:Radiation Dosage