Photoacoustic and electron microscopic studies of reminerlized artificially carious enamel and dentin

Abstract
Photoacoustic (PA) spectroscopy and scanning electron microscopy (SEM) have been employed to investigate remineralized artificially carious enamel as well as dentin. The remeniralization process was carried out by applying bioactive glass particles and mineralizing solutions either directly or after the specimen was first treated with Zeolite powder. The PA was carried out to evaluate the change in the thermal parameters (diffusivity, effusivity and conductivity) quantitatively. The remineralization process was evaluated by comparing the thermal parameters to those of the healthy tissue. PA measurements show that; the values of thermal conductivity of the normal tissues (enamel: 0.9 W m^-1 K^-1 and dentin: 0.58 W m^-1 K^-1) were altered by caries to be (enamel: 0.72 W m^-1 K^-1 and dentin: 0.44 W m^-1 K^-1) and they approach their normal values after the application of the different mineralizing agents. Also the results indicate that; Bioactive glass enhances the thermal parameters of artificially carious enamel and dentin (considering the healthy values as a reference), slightly more than the mineralizing solution. Furthermore, PA measurements show that the application of Zeolite powder enhances the effect of the mineralizing agent. In order to augment the PA results, SEM was used to depict surface topography, for each treated tissue.