Optical properties of dental enamel in the mid-IR determined by pulsed photothermal radiometry

Time-resolved thermal emission measurements were used to determine the absorption coefficients of dental enamel at 9.6, 10.3, and 10.6 μm. Time resolved thermal emission from the enamel surface was modeled using numerical simulations of heat conduction coupled with radiative heat transfer. Thermal emission was measured using HgCdZnTe detectors during IR laser irradiation with λ9.6, 10.3 and 10.6 μm CO₂ laser pulses of 2-μs duration. The method was verified in regions of low absorption for which absorption coefficients were available using direct transmission measurements, The absorption coefficients were determined to be 8000, 1125, and 825 cm^-1 at 9.6, 10.3, and 10.6 μm, respectively. These results have important implications in the development of CO₂ lasers for the ablation and modification of dental hard tissue