Abstract
The purpose of this study is to develop a reliable stereoradiographic system to observe teeth and their supporting structures. A film holder, a bite wing, and a pointer were the main components of thecollimting device. Two x-ray tubes and a stretching pointer were assembled which was mounted on the 5 joint arm. The distance between the foci of the two tubes was 9.6cm. The main beams of the 2 tubes cross to each other at 55cm from the mid point of the foci. The angle made by the 2 beams was 10 degree. The geometric relationship between the x-ray tubes and the collimator was maintained by adjusting both pointers. Two films were used to obtain a stereo-image. A film was mounted on the film holder and irradiated by a x-ray tube, then the film was changed and the irradiation was made by another tube.
A stereoscope (Topcon Co. Ltd.) was used to observe the stereo-image. If the observer was accustomed to it, stereognosis of the image was also possible by unaided eye observation.
Extracted teeth, dry human upper and lower jaws were used to evaluate the system. A few clinical investigations were also made. A Piece of wire was inserted to the periodontal pocket to indicate the bottom.
The stereoradiographic system described here is useful to obtain 3-dimensional image of teeth and their supporting structures.
