[Dental application of imaging information. Evaluation of optimum tube voltages].

The subjective contrast including the density component of radiograph as well was aimed at. In relation to the intraoral radiographs (18 cases) of the left first molar of the mandible and its surrounding tissue taken using tube voltage of 60-90 kV, the radiographs were evaluated based on the mean of the extracted subjective contrast values, resulting in the following findings: 1. A tendency was observed in the enamel and dentine of the central portion of crown, for the mean of the extracted subjective contrast values using tube voltage of 70 kV to be lower than that with 60 kV. 2. A tendency was found in the dentine on the cement side of the mesial and distal cervical portion and the periodontal membrane space of the cervical portion, for the mean of the extracted subjective contrast values to generally become larger as the tube voltage was increased. 3. A tendency was recognized in the alveolar lamina dura of the mesial and distal marginal alveolar portion, for the mean of the extracted subjective contrast values to become larger as the tube voltage was increased. From intraoral radiographs of teeth, the findings mentioned above have proved that good radiographs will be created using a tube voltage of 70 kV for enamel and dentine, and using 60 kV for dentine and cement in the area of the cervical portion or in case of the periodontal tissue.