title: Thermal effects of CO2 laser on the pulpal chamber and enamel of human primary teeth: an in vitro investigation.
abstract: OBJECTIVE
  Thermal effects of direct exposure of the pulp chamber to CO2 laser irradiation were evaluated and potentially safe parameters for its clinical application were determined.
  
  
  METHODS
  Using conventional methods, the pulp chambers of freshly extracted primary cuspids were exposed and then subjected to CO2 laser irradiation at the following parameters: 2, 4, 6, 8, 10, 15, and 20 Watts power settings; 0.76 mm diameter spot size; total energy densities between 4-1,058 J/cm2; exposure time between .01-60 s. Exposures in the continuous wave mode were performed in some specimens. In others, single firings of a .01 s pulse duration and a 1 s pulse interval were conducted. Temperature measurements were conducted using a thermocouple and thermal camera.
  
  
  RESULTS
  Significant statistical differences in maximum temperature rise on enamel were observed in groups that received total energy densities > or = 8 J/cm2 (P < or = 0.01); within the pulp chambers these were observed in groups that used > or = 44 J/cm2 (P < or = 0.01).
  
  
  CONCLUSIONS
  Parameters appropriate for pulpotomy were observed at energy densities up to 176 J/cm2 in the continuous wave mode and 264 J/cm2 using single pulses, wherein temperature rises below 5.5 degrees C were recorded on tooth surface.
authors.affiliation: Beckman Laser Institute and Medical Clinic, University of California, Irvine 92715, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Arrastia
authors.forename: P
authors.initials: P
authors.lastname: Wilder-Smith
authors.forename: M W
authors.initials: MW
authors.lastname: Berns
mesh_terms: D001831:Body Temperature; D002245:Carbon Dioxide; D003481:Cuspid; D003743:Dental Enamel / Q000503:physiopathology*; D003786:Dental Pulp Cavity / Q000503:physiopathology*; D006358:Hot Temperature; D006801:Humans; D053685:Laser Therapy / Q000379:methods; D011672:Pulpotomy; D012449:Safety; D013814:Thermal Conductivity; D013817:Thermography; D013821:Thermometers; D013997:Time Factors; D014094:Tooth, Deciduous / Q000503:physiopathology*
chemical_list: D002245:Carbon Dioxide