Abstract
Application and development of new methods in caries prevention is of paramount importance to reduce the incidence of chronic cases of the caries disease and to preserve dental structure. In this work, we tested nanosecond pulsed Nd:YAG laser on enamel surface examining the changes laser-induced by means SEM, EDS, and FTIR. SEM revealed, the existence of melted zone and bubble inclusions when 40 J/cm2 (τ=6 ns, 5 Hz) was applied on human sound enamel surface. The morphological alteration to 10 J/cm2 (τ=6 ns, 5 Hz) and to 20 J/cm2 (τ=200 ns, 7 Hz) no presented melting aspect, but a greater number of bubble inclusions. We have indicated that the Ca/P ratio increased to irradiation conditions employed here. In our previous study, the combination of the laser parameters not produce an excessive increase in temperature. The temperature variation was less than 2.5°C in the dental pulpal, following application of the energy density of 40 J/cm2. Our results suggest that nanosecond pulsed Nd:YAG laser can be used to obtain minimal morphological alteration associated with a chemical reorganization enhancing the microhardness values and consequently inhibiting the acid dissolution by bacterial agents. In this work, the Vickers microhardness was quantified. Our results of FTIR analysis indicated that the laser effects occurring substantially in the organic compounds (such as water and proteins groups) and are reduced for mineral contend (such as phosphate and carbonate groups).