Abstract
In this study, the wavelength of a CO2 laser was modified to 9.45µn;m (Modi-CO2 laser) and the cutting efficiency of Modi-CO2 laser was evaluated. We used the freshly extracted human molars without carious regions. The dentin surface of the thawed teeth was polishing with alumina (0.05 mm). Modi-CO2 laser was irradiated by TEA-CO2 laser. Modi-CO2 laser was irradiated on the polished dentin surface under the irradiation conditions of 1 MW/pulse and 1, 5, 10 and 50 pulses. The pulse width of one pulse was set to 100 ns. The Modi-CO2 laser-irradiated dentin surfaces were Au-spattered and were observed by an electron surface roughness analyzer. The volume lost by the irradiation of the laser was calculated from the diameter and the depth of cavity. The relationship between the lost volume and the irradiation energy was statistically analyzed by one-way ANOVA and Scheffe's test (p<0.05). No measurable loss of dentin was detected with Modi-CO2 laser-irradiation of 1 and 5 pulses. The lost volumes of dentin with 10 and 50 pulses were 143333 and 342333 mm3. The lost volume by the irradiation of Modi-CO2 laser significantly increased with an increase of the pulse of Modi-CO2 laser.
