title: In vitro study of dentin hypersensitivity treated by Nd:YAP laser and bioglass.
abstract: OBJECTIVE
  An ideal material has yet to be discovered that can completely treat dentin hypersensitivity. However, if a highly biocompatible material such as bioglass, could be melted by laser irradiation to achieve better sealing depth for dentinal tubules, it may subsequently bond to dentin structures under a physiological environment and offer a prolonged therapeutic effect.
  
  
  METHODS
  The authors used four types of energy parameters to melt the composition-modified bioglass. These four types were 30 Hz, 330 mJ/pulse (G+ mode), 30 Hz, 160 mJ/pulse (G- mode), 10 Hz, 400 mJ/pulse (D+ mode), and 10 Hz, 200 mJ/pulse (D- mode). The temperature elevation, occlusive depth of bioglass, and phase changes in the bioglass after laser irradiation were evaluated by means of scanning electron microscope (SEM), thermometer, and X-ray diffractometer (XRD).
  
  
  RESULTS
  The occlusive depths of 2 and 10 microm in the dentinal tubules were achieved when the bioglass underwent 30 Hz, 160 mJ/pulse (G- mode) and 30 Hz, 330 mJ/pulse (G+ mode) of laser treatments, respectively. The bioglass experienced a temperature increase of less than 600 degrees C, and no phase transformation was observed after Nd:YAP laser irradiation.
  
  
  CONCLUSIONS
  The melting point of a composition-modified bioglass could be reduced and its use plus Nd:YAP laser have the potential in clinical use to treat dentin hypersensitivity.
authors.affiliation: Graduate Institute of Clinical Dentistry, College of Medicine, National Taiwan University Hospital, No. 1, Chang-Te Street, Taipei, Taiwan, ROC.
authors.forename: Bor-Shiunn
authors.initials: BS
authors.lastname: Lee
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Chang
authors.forename: Weng-Pin
authors.initials: WP
authors.lastname: Chen
authors.forename: Wan-Hong
authors.initials: WH
authors.lastname: Lan
authors.forename: Chun-Pin
authors.initials: CP
authors.lastname: Lin
mesh_terms: D002516:Ceramics / Q000627:therapeutic use*; D018360:Crystallography, X-Ray; D003738:Dental Cements / Q000627:therapeutic use*; D003806:Dentin Permeability; D003807:Dentin Sensitivity / Q000628:therapy*; D006358:Hot Temperature; D006801:Humans; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D008963:Molar; D009354:Neodymium
chemical_list: C022107:Bioglass; D003738:Dental Cements; D009354:Neodymium