title: Argon laser irradiation effects on sound root surfaces: in vitro scanning electron microscopic observations.
abstract: OBJECTIVE
  The purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effect of low fluence (energy density of 11.5 J/cm2 and 100 J/cm2) argon laser irradiation on the surface morphology of sound root surfaces.
  
  
  BACKGROUND
  Previous laboratory investigations have shown that argon laser irradiation of root surfaces provided a protective effect against in vitro cariogenic challenges.
  
  
  METHODS
  Root surfaces of extracted human molars were sectioned into treatment quarters: 1) mesiobuccal--no treatment control; 2) mesiolingual--low fluence argon laser irradiation (0.231 Watts, 11.5 J/cm2 for 10 seconds); 3) distobuccal--no treatment control; and 4) distolingual--higher fluence argon laser irradiation (2.0 Watts, 100 J/cm2 for 10 seconds). All surfaces were critical-point dried, coated with platinum and paladium under vacuum, and evaluated qualitatively for intactness, surface morphology, surface deposits, and porosities in a blinded fashion by scanning electron microscope.
  
  
  RESULTS
  The argon lased root surfaces demonstrated alterations of root surfaces with creation of surface globular particulate material, microporosities, and depressions. Both low- and high-fluence lased root surfaces showed areas with plaque-like plates with fine punctuate oval particulate material on their surfaces.
  
  
  CONCLUSIONS
  Argon laser irradiated root surfaces produce surface granular to globular deposits that may provide readily mobilized tooth mineral, which may become redeposited into the underlying root surface during a cariogenic challenge and enhance resistance to caries formation. In addition, microporosities created by the argon laser may provide a means for bonding fluoride-releasing restorative and preventive materials to root surfaces and further improve the root surfaces' ability to resist cariogenic challenges.
authors.affiliation: Department of Community and Preventive Dentistry, Creighton University, School of Dentistry, Omaha, Nebraska, USA. ghwester@creighton.edu
authors.forename: G H
authors.initials: GH
authors.lastname: Westerman
authors.forename: M J
authors.initials: MJ
authors.lastname: Hicks
authors.forename: C M
authors.initials: CM
authors.lastname: Flaitz
authors.forename: R J
authors.initials: RJ
authors.lastname: Blankenau
authors.forename: G L
authors.initials: GL
authors.lastname: Powell
mesh_terms: D001128:Argon; D006801:Humans; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000528:radiation effects / Q000648:ultrastructure; D017213:Root Caries / Q000517:prevention & control*; D014092:Tooth Root / Q000528:radiation effects* / Q000648:ultrastructure
chemical_list: D001128:Argon