Interaction of pulsed carbon dioxide laser beams with teeth in vitro.
Beams of pulsed carbon dioxide lasers with energy densities of about 10, 100 or 200 J/mm2 have been applied perpendicularly to third molars in vitro for the purpose of preparing cavities or pin holes for retention. A pulsed beam with an energy density of about 10 J/mm2 produced a hole approximately 2 mm deep with a diameter of about 0.2 mm. With a beam of 100 J/mm2 the hole produced penetrated the tooth to a depth of 4 mm. Minor cracks around the hole in both enamel and dentin could be observed. Around the position where the beam entered the enamel matrix a white mineralized layer was observed, while a brown discoloration was formed around the hole in the dentin at the beam exit. With an energy density of 200 J/mm2 the formation of cracks and discoloration was very pronounced. X-ray diffraction of lased tissue revealed an apatite structure. The wall in the lased hole exhibited a Vicker hardness number similar to that of enamel.
D002245:Carbon Dioxide; D006244:Hardness; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D014070:Tooth / Q000033:anatomy & histology* / Q000502:physiology / Q000601:surgery; D014961:X-Ray Diffraction
D002245:Carbon Dioxide