Visualization of localized elastic properties in human tooth and jawbone as revealed by scanning acoustic microscopy

The elastic properties of human canine and supporting alveolar bone are measured by the distribution of localized speed of sound using scanning acoustic microscopy. Methods for the dynamic, non-destructive diagnostics of dental hard tissues can have a key role in the early detection of demineralization processes and carious lesions, and they are supposed to open the possibility of early dental restorations. The localized distribution of the ultrasound velocity in canine tooth and alveolar bone was obtained using scanning acoustic microscopy with a 5- and 30-MHz transducer. An acoustic material signature curve signifies the interference of the waves and quantitatively maps the localized speed of sound in alveolar bone and the canine tooth. Seven samples, consisting of alveolar jawbone and tooth sliced along the coronally apical axis, were investigated. The average speed of sound was determined along three independent cross sections at enamel, dentin and cortical bone. The average speed of sound in enamel, bone and dentin was SD 3460 ± 193 m/s, 3232 ± 113 m/s and 2928 ± 106 m/s. The distribution of sound wave propagation reveals a decrease in sound speed from the peripheral parts within the enamel and dentin layers toward the proximal zones. These results prove the possibility of linking the elastic properties to different areas within the osseous and dental hard tissues and visualize them in an extremely high local resolution. The results serve as a basis for further study and substantiate the enormous potential of ultrasound based analysis in the field of dento-alveolar diagnosis.