Abstract
Recently, rotational panoramic apparatuses for TMJ radiography have been undergoing rapid improvement. One apparatus (AUTO III, Asahi Roentgen Co., Ltd., Kyoto, Japan) can photograph the right and left temporomandibular joints (TMJ) when opening and closing the mouth, exposing the images in each quadrant of the same film. This apparatus, however, is considered as a combination of tomography and scanography, and it is not obvious what portion of the condyle contour is taken. The images taken by such apparatuses have not been evaluated and reported on.
The purpose of this study was to evaluate the accuracy between the images and the real condyles (objects), and to examine the usefulness of TMJ images taken by rotational panoramic radiography in children. The TMJ of three human dry skulls with Hellman's dental developmental stages IIA, IIIA and IVA were used in this study. They were radiographed in the positions recommended by the manufacturer and in other positions of a different angle in order to obtain images taken at a different angle of the X-ray beam. The images of the TMJ were analyzed by visual evaluation.
The results were as follows:
1. Concerning reproducibility of the condyle contour in the IIA and IIIA stages, the method using the apparatus (AUTO III, by Asahi roentgen Co., Ltd., Kyoto, Japan) was better than the modified Schaller method.
2. In each of Hellman's dental developmental stages, the images of the contour around the top of the condyle were the most salient part of the TMJ.
3. When the dry skulls were moved upward, the images of the TMJ could be reproduced more clearly without superimposition of the bony structures.
4. Ear-rods were needed for better reproducibility of the images of the TMJ.
As a result of this evaluation, it was concluded that a TMJ mode (position)of a rotational panoramic apparatus is considered to be useful for screening the TMJ of children.
