Thermal effects on CO2 laser-irradiated dental enamel at 9.3 9.6 10.3 and 10.6 microns

摘要

Abstract: Human and bovine enamel samples were irradiated with a pulsed CO$-2$/ laser at $lambda $EQ 9.3, 9.6, 10.3, and 10.6 $mu@m with 5 - 10 J/cm$+2$/ pulses of 50 - 500 $mu@s duration in order to determine the required energy densities needed to fuse the enamel surface. The resulting temperature rise at the sample surface ranged from 500 to 1500$DGR@C, as measured by a HgCdZnTe detector. The temperature was significantly higher at 9.3 and 9.6 $mu@m than at 10.3 and 10.6 $mu@m for the same absorbed energy. Scanning electron micrographs of the irradiated enamel revealed surface changes that were consistent with the surface temperature observations. The temperature rise at the ceiling of the pulse chamber determines the risk of pulpal necrosis. This temperature was measured using thermocouples and a thermal imaging camera for different pulse repetition rates and number of pulses. These results indicate that the more efficient absorption at $lambda $EQ 9.3 and 9.6 $mu@m may be used to fuse enamel at lower laser energies, therefore requiring less energy, significantly reducing the risk of pulpal necrosis during laser treatment. !19