Objective: During intraoral radiography, the extent to which fingers are exposed to radiation should be reduced as much as possible. We compared the exposure doses between two image receptor-holding methods, a finger-based method and a method involving special devices. Then, we verified the usefulness of the devices. Materials and Methods: The maxillary right first molar of a dental x-ray simulator mannequin was chosen as the target tooth for the intraoral x-ray examinations. Irradiation （60kV, 6mA, 0.32s） was performed using a short cone-type x-ray head. Small （10×10×2mm） OSL （optically stimulated luminescence） dosimeter tips were used to measure the radiation doses. In addition to the conventional finger-based method, two types of devices were used to hold the image receptors: the “Smart-grip”, a toothbrush-type device, and the “Smart-wing” system, which combines an occlusion holding device and a rectangular iris. We measured the radiation dose delivered to the back of the receptor when the fingers, “Smart-grip”, and “Smart-wing” were used. In addition to the back of the receptor, the radiation doses at two distant points were also measured. The reverse-side radiation doses of different image receptors （analog film, imaging plates） were also compared. Results and Discussion: The radiation dose delivered to the fingertips was 0.178mGy/exposure when the image receptor was held with the fingers, whereas it was 0.072mGy/exposure when an x-ray film was used with a sheet of lead foil. The radiation dose delivered to the reverse side of the image receptor was 0.018mGy/exposure when the “Smart-grip” was used. The radiation dose delivered to the handle of the “Smart-grip” was 0.006mGy/exposure, which was almost the same as the background level. When the “Smart-wing” was used, the dose delivered to the back of the image receptor was 0.024mGy/exposure. Conclusion: It was suggested that the radiation dose delivered to the fingers during intraoral radiography can be markedly reduced by using the “Smart-grip” or “Smart-wing”.
