title: Effects of copper vapor laser radiation on the root canal wall of human teeth: a scanning electron microscope study.
abstract: OBJECTIVE
  The aim of this study is to analyze the effects of copper vapor laser radiation on the radicular wall of human teeth.
  
  
  METHODS
  Immediately after the crowns of 10 human uniradicular teeth were cut along the cement-enamel junction, a chemical-surgical preparation of the radicular canals was completed. Then the roots were longitudinally sectioned to allow for irradiation of the surfaces of the dentin walls of the root canals. The hemi-roots were separated into two groups: one (control) with five hemi-roots that were not irradiated, and another (experimental) with 15 hemi-roots divided into three subgroups that were submitted to the following exposure times: 0.02, 0.05, and 0.1 s. A opper vapor laser (510.6 nm) with a total average power of 6.5 W in green emission, frequency of 16.000 Hz, and pulse duration of 30 ns was used.
  
  
  RESULTS
  The results obtained by scanning electron microscope analysis showed the appearance of a cavity in the region of laser beam impact, with melting, recrystallization, and cracking on the edges of the dentin of the cavity due to heat diffusion.
  
  
  CONCLUSIONS
  We determined that the copper vapor laser produces significant morphologic changes in the radicular wall of human teeth when using the parameters in this study. However, further research should be done to establish parameters that are compatible with dental structure in order to eliminate thermal damages.
authors.affiliation: Academic Group of Studies and Research with Lasers in Dentistry, Sao Paulo State University, School of Dentistry, Sao Jose dos Campos, Sao Paulo, Brazil. niccolifosjc.unesp.br
authors.forename: Walter
authors.initials: W
authors.lastname: Niccoli-Filho
authors.forename: Maria Cláudia Garcia
authors.initials: MC
authors.lastname: da Silveira
authors.forename: Nilson Dias
authors.initials: ND
authors.lastname: Vieira
authors.forename: Rudimar
authors.initials: R
authors.lastname: Riva
mesh_terms: D003300:Copper; D003786:Dental Pulp Cavity / Q000528:radiation effects* / Q000601:surgery* / Q000648:ultrastructure; D003804:Dentin; D006801:Humans; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning
chemical_list: D003300:Copper