A basic and clinical evaluation of our newly developed radiographic orthopantomography in studying the TMJ

Temporomandibular arthrosis has been reported in many fields: oral surgery, dental prosthetics, otolaryngology, radiology, psychosomatic medicine etc... Roentgenographic examination plays an important role in the diagnosis of temporomandibular arthrosis. There have been studies on various types of roentgenography of the temporomandibular joint, but because its anatomical morphology is so complicated that it is difficult to obtain an adequate roentgenograph. Thus, no definite method of roentgenography has been clearly established. We developed a new method of roentgenography that takes advantage of the characteristics of orthopantomography, and analyzed our results statistically. The following results were obtained: 1) As conditions for roentgenography, the optimal tube voltage was 60 ∼ 75 KVp, but this varied according to sex and age; the optimal tube current was 15 mA. 2) The optimal position of the head in the anteroposterior position was 10 mm in front of the standard point, and that in the vertical position was the central part of the film. 3) The optimal position of the head was reached when the OM line was horizontal. 4) On the basis of the data obtained from these basic experiments, images from standard roentgenography were compared statistically with those from the modified method of Schuller in patients with temporomandibular arthrosis. There was a significant difference between the images (P < 0.01). These results demonstrated that this method of roentgenography may be useful in standardizing X-ray procedures, provides images of temporomandibular arthrosis of high reproductive quality, suggesting that this method may be adequate for more definitive diagnoses. (author)