title: Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiation.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface.
  
  
  METHODS
  60 root samples were irradiated for 1 min each either with 60 mJ/p, 80 mJ/p and 100 mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples.
  
  
  RESULTS
  Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples.
  
  
  CONCLUSIONS
  This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins.
authors.affiliation: Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Slovenia. boris.gaspirc@ijs.si
authors.forename: B
authors.initials: B
authors.lastname: Gaspirc
authors.forename: U
authors.initials: U
authors.lastname: Skaleric
mesh_terms: D000538:Aluminum Silicates; D000577:Amides / Q000032:analysis / Q000145:classification; D000704:Analysis of Variance; D003804:Dentin / Q000528:radiation effects / Q000648:ultrastructure; D004058:Diffusion; D004578:Electron Spin Resonance Spectroscopy; D004871:Erbium; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D008903:Minerals / Q000528:radiation effects; D009354:Neodymium; D013055:Spectrophotometry, Infrared; D013223:Statistics as Topic; D014092:Tooth Root / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D000577:Amides; D008903:Minerals; D009354:Neodymium; D015019:Yttrium; D004871:Erbium