title: Histopathological changes in dental pulp irradiated by Er:YAG laser: a preliminary report on laser pulpotomy.
abstract: OBJECTIVE
  The effects of Er:YAG laser irradiation on the pulp tissue during a pulpotomy procedure were evaluated histopathologically.
  
  
  BACKGROUND
  The effects on pulp tissue during laser pulpotomy using Er:YAG laser irradiation are not clear.
  
  
  METHODS
  Sixty mesial root canals of mandibular first molars in rats were divided into four groups. In three of these groups, root canals were irradiated using an Er:YAG laser at 2 Hz and 34, 68, and 102 mJ/pulse for 15 sec. Non-irradiated canals served as controls. The effects of laser irradiation on the remaining pulp tissue and periodontal tissues were evaluated at 0 days, 2 days, and 1 week after irradiation under light microscopy.
  
  
  RESULTS
  At 1 week after treatment, no inflammation or resorption was observed in any cases in the control or 34 mJ/pulse-irradiated groups. However, moderate to severe inflammation was observed in 9 of 10 cases (90%) in the 68 and 102 mJ/pulse-irradiated groups.
  
  
  CONCLUSIONS
  These results suggest that effects on pulp tissues during a pulpotomy procedure by Er:YAG laser irradiation are minimal, if appropriate parameters are selected, and this is a potential therapy for pulpotomy of human teeth.
authors.affiliation: Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan. yukimura@senzoku.showa-u.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kimura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yonaga
authors.forename: Keiko
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Haruji
authors.initials: H
authors.lastname: Watanabe
authors.forename: Xiaogu
authors.initials: X
authors.lastname: Wang
authors.forename: Koukichi
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D003782:Dental Pulp / Q000473:pathology* / Q000528:radiation effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar