Applications of single laser pulse from Nd:doped lasers for cleaning of small diameter carious lesions. Modelling and analytical study

Abstract

We report on an analytical study with physical modelling, some additional experimental studies and computer programming of the cleaning of initial carious lesions (1 - 3 mm in diameter) with a single laser pulse from Nd:doped (Nd:YAG and Nd:Glass) lasers (wavelength 1.06 μm). The analysis is based on experimental data from our preliminary study and aims to develop a method to predetermine the necessary laser pulse parameters for reasonable cleaning. To obtain such laser pulse parameters, we considered the conversion of light energy into heat, the propagation of incident light and the resulting heating of the dental tissue, the induced ablation processes associated with lesion cleaning, and the formation of the necessary hole in combination with acceptable heating of the pulp chamber and prevention of enamel crack formation. Cleaning is naturally associated with the bactericidal effect. The study, except for the estimation, confirms that the use of single light pulses of the considered lasers with energies from 1.3 to 4.5 J, densities from 40 to 120 J/cm2, pulse duration from a few hundred microseconds to ~2 ms (i.e., in the simplest, natural, free mode of operation of the noted lasers) can be considered as a promising method to start caries treatment.