抄録
The detectability of osseous abnormalities of the mandibular condyle in two different projections using the panoramic x-ray unit was examined. Seventy two autopsy mandibular condyles with macroscopic osseous changes were selected. Corrected sagittal and frontal tomography and panoramic radiography were performed with the condyle in the tomographic layer. Panoramic radiography included two different projections, one at a horizontal angulation of 18° postero-medially from the frontal plane (lateral mode) and another 30° antero-medially (oblique mode). The vertical angulation of the x-ray tube was fixed upward 3° for the lateral and oblique projections. Radiographic concavity, osteophyte, sclerosis and erosion of the condyles were recorded. Sensitivity of the detection of these osseous abnormalities revealed by the two panoramic projections were calculated based on sagittal and frontal tomographic findings as a gold standard. Sensitivity of the detection of each abnormality revealed by lateral panoramic projections/oblique projections/combination of lateral and oblique projections were as follows. Concavity; 0.49/0.22/0.63, osteophyte; 0.69/0.38/0.69, erosion; 0.42/0.71/0.71, sclerosis; 0.46/0.38/0.50, total; 0.73/0.51/0.75. The oblique projection was essential for the detection of erosion, while the lateral projection for osteophyte. When panoramic radiography is employed as a scouting method for temporomandibular joint disease, two different projections are necessary to detect osseous abnormalities sensitively.
