Terahertz time-domain spectroscopy of tooth components for caries diagnosis

To confirm the possibility of identification between dentin and decalcified dentin in the terahertz (THz) region, transmission characteristics of these tooth components were measured by terahertz time-domain spectroscopy (THz-TDS). The refractive index and absorption coefficient of decalcified dentin are found to be lower compared to those of dentin. These results suggest the potential application of THz waves in caries diagnosis.