title: Pulpal response to exposure with Er:YAG laser.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the pulpal response to the Er:YAG laser after accidental exposure of the pulp.
  
  
  METHODS
  Cavities were prepared, and pulps were exposed by either Er:YAG laser or mechanically by a slow-speed conventional handpiece (control group) in 76 maxillary first molars of male Wistar rats. Rats were killed immediately, at 3 days, 1 week, and 2 weeks. Histopathologic examinations of the pulp at the exposure site were performed and evaluated with the Mann-Whitney U test (P <.05).
  
  
  RESULTS
  The Er:YAG laser group showed no bleeding and no dentin chips at the exposure site immediately after pulp exposure. However, they displayed an area of blood extravasation near the exposure site. Subsequently, the Er:YAG laser group formed dentin bridges at the exposure site more frequently than the control group. The Er:YAG laser group demonstrated more reparative dentin formation near the exposure site than the control group, especially at 2 weeks, which was highly significant (P <.01).
  
  
  CONCLUSIONS
  According to the results of this study, Er:YAG laser-exposed pulp tissue demonstrated good healing capacity with the formation of a dentin bridge and reparative dentin. However, further investigations are suggested to study the effect of the blood extravasation, which appeared near the laser exposure sites.
authors.affiliation: Department of Pediatric Dentistry, Tokyo Medical and Dental University, Japan. asiri.pedo@dent.tmd.ac.jp
authors.forename: J A
authors.initials: JA
authors.lastname: Jayawardena
authors.forename: J
authors.initials: J
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Moriya
authors.forename: Y
authors.initials: Y
authors.lastname: Takagi
mesh_terms: D000538:Aluminum Silicates; D000818:Animals; D002126:Calcium Hydroxide / Q000627:therapeutic use; D003737:Dental Cavity Preparation / Q000009:adverse effects / Q000295:instrumentation; D003782:Dental Pulp / Q000473:pathology / Q000528:radiation effects*; D003785:Dental Pulp Capping; D003789:Dental Pulp Exposure / Q000503:physiopathology; D003804:Dentin / Q000473:pathology / Q000528:radiation effects; D003809:Dentin, Secondary / Q000473:pathology / Q000528:radiation effects; D004871:Erbium; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000473:pathology / Q000517:prevention & control; D007834:Lasers; D008297:Male; D008903:Minerals / Q000627:therapeutic use; D008963:Molar; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D014945:Wound Healing / Q000528:radiation effects; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D008903:Minerals; C025702:Dycal; D015019:Yttrium; D004871:Erbium; D002126:Calcium Hydroxide