title: Effects of Er:YAG laser irradiation on human dentin: polarizing microscopic, light microscopic and microradiographic observations, and FT-IR analysis.
abstract: OBJECTIVE
  The effects of Er:YAG laser irradiation on dentin have not been sufficiently investigated. The purpose of this study was to investigate the effects of Er:YAG laser irradiation on dentin.
  
  
  METHODS
  After cavities were prepared using Er:YAG laser irradiation or rotary cutting instruments, histological observations of cavity-floor dentin utilizing polarizing microscopy, microradiography and light microscopy, and analysis of composition of cavity-floor dentin using Fourier-transformed (FT-IR) spectrometry were conducted.
  
  
  RESULTS
  In the laser-treated side, a deeply stained basophilic layer was observed. The number of odontoblastic processes present was obviously less in the laser-treated side than in the bur-treated side. FT-IR analysis revealed that compared to the bur-treated side, a broad background peak at around 1,600 cm(-1) was present.
  
  
  CONCLUSIONS
  Er:YAG laser irradiation might have denatured the organic materials of dentin.
authors.affiliation: Department of Endodontics and Operative Dentistry, School of Dentistry at Tokyo, Nippon Dental University, Tokyo, Japan. yaeko-n@tokyo.ndu.ac.jp
authors.forename: Yaeko
authors.initials: Y
authors.lastname: Ishizaka
authors.forename: Toru
authors.initials: T
authors.lastname: Eguro
authors.forename: Toru
authors.initials: T
authors.lastname: Maeda
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D001491:Basophils / Q000473:pathology; D003737:Dental Cavity Preparation / Q000379:methods; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure; D004801:Eosine Yellowish-(YS); D004871:Erbium; D006801:Humans; D007834:Lasers / Q000009:adverse effects*; D008852:Microradiography; D008853:Microscopy / Q000379:methods*; D008859:Microscopy, Polarization; D009804:Odontoblasts / Q000473:pathology; D012394:Rosaniline Dyes; D017550:Spectroscopy, Fourier Transform Infrared; D013194:Staining and Labeling / Q000379:methods; D014070:Tooth / Q000528:radiation effects / Q000648:ultrastructure; D015019:Yttrium
chemical_list: D012394:Rosaniline Dyes; C006898:carbol-fuchsin solution; D015019:Yttrium; D004871:Erbium; D004801:Eosine Yellowish-(YS)