Monte-Carlo Modelling of light propagation in hard dental tissues

Abstract

In the Monte-Carlo model, we simulated the propagation of visible light and the temperature distribution in human tooth, which reflects the energy deposited in the tooth by the laser. As a turbid medium, differences in absorption and scattering coefficients of the enamel and dentine must be taken into account. These data are not completely established in the literature in the visible range. The results are compared with experimental data of Cu-HyBrID laser light propagation in human molar teeth, in order to evaluate the scattering coefficient. The Cu-HyBrID laser emits green (510 nm) and yellow (578 nm) radiation with high output peak power (20 kW) at high repetition rates (13.7 kHz) and there is almost no report of its use in Dentistry. This work aims to correlate the Cu-HyBrID energy deposition with the tooth thermal response. The tooth is predominantly a scattering medium (absorption much lower than scattering) and small variations in the absorption coefficient do not reveal significant alterations in the light distribution curve. According to the simulation, most of the laser energy is accumulated on enamel-dentine junction and the tooth thermal response is strongly affected by the value of the absorption coefficient, which is not yet precisely known.