title: Effect of Er:YAG and CO2 lasers with and without sodium fluoride gel on dentinal tubules: a scanning electron microscope examination.
abstract: OBJECTIVE
  The aim of this pilot study was to evaluate the occluding effect of erbium:yttrium-aluminum-garnet (Er:YAG) and carbon dioxide (CO2) lasers as monotherapy and in combination with topical fluoride gel on human dentinal tubules by scanning electron microscopic (SEM) examination.
  
  
  METHODS
  Thirty-six dentine specimens with exposed dentinal tubule orifices were included in this study. The samples were divided into six groups. Group A served as controls, group B was treated with 2% sodium fluoride (NaF) gel alone, groups C and D were irradiated with Er:YAG (30 Hz, 60 mJ, for 10 sec) and CO2 (1 W, continuous-wave mode, for 10 sec) lasers, respectively, and groups E and F received NaF gel plus Er:YAG and CO2 laser irradiation, respectively.
  
  
  RESULTS
  Under SEM analysis, numerous exposed, normally-structured dentinal tubule orifices were seen in the control group. Some narrowing of the exposed tubule orifices was seen in group B. A melted, irregular surface structure with small peaks was observed in group C. The surface of group D also had a melted appearance, but a fibrillar deformation of the surface structure was seen on the specimens. However, the surface morphologies seen were remarkably different in groups E and F. While the tubule orifices were obviously occluded but depressed into craters in group E, the surface structure of group F primarily showed a smooth appearance. In terms of numbers and diameters of open dentinal tubules, there was no significant difference between the laser-alone and combination groups, whereas the difference was found to be significant when the control and NaF groups were compared with each other and the remaining laser-alone or combination groups.
  
  
  CONCLUSIONS
  The dentinal tubules in all laser groups were occluded after laser irradiation, but more marked occlusions were observed when laser and NaF gel were combined.
authors.affiliation: Department of Periodontology, Yeditepe University, Istanbul, Turkey. gokserc@yahoo.com
authors.forename: Gokser
authors.initials: G
authors.lastname: Cakar
authors.forename: Bahar
authors.initials: B
authors.lastname: Kuru
authors.forename: Sebnem Dirikan
authors.initials: SD
authors.lastname: Ipci
authors.forename: Zeynep Merve
authors.initials: ZM
authors.lastname: Aksoy
authors.forename: Imer
authors.initials: I
authors.lastname: Okar
authors.forename: Selcuk
authors.initials: S
authors.lastname: Yilmaz
mesh_terms: D000328:Adult; D003804:Dentin / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D005460:Fluorides, Topical / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D054020:Lasers, Gas; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: D005460:Fluorides, Topical; D012969:Sodium Fluoride