title: Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching.
abstract: BACKGROUND
  The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching.
  
  
  METHODS
  The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05).
  
  
  RESULTS
  A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching.
  
  
  CONCLUSIONS
  The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material.
  
  
  BACKGROUND
  Laser, diode, dentin, tubule, diameter.
authors.affiliation: Assistant professor. Department of Operative Dentistry, Dental faculty, Tehran University of Medical Sciences, International campus, Tehran, Iran.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Kiomarsi
authors.affiliation: Doctor. Tehran University of Medical Sciences, International campus, Tehran, Iran.
authors.forename: Soheil
authors.initials: S
authors.lastname: Salim
authors.affiliation: Assistant professor. Department of Endodontics, Dental faculty, Tehran University of Medical Sciences, International campus, Tehran, Iran.
authors.forename: Pegah
authors.initials: P
authors.lastname: Sarraf
authors.affiliation: Doctor. Tehran University of Medical Sciences, International campus, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Javad-Kharazifard
authors.affiliation: PhD candidate. Laser Research Center of Dentistry (LRCD), Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush