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Observer performance and diagnostic outcome in the diagnosis of the disk position of the temporomandibular joint by arthrography were investigated. Three different radiographic techniques were studied: fluoroscopy, fluoroscopy in combination with lateral transcranial radiography, and fluoroscopy in combination with corrected sagittal tomography. Seven observers were asked to assess 30 joints representing three diagnoses, namely superior disk position and anterior disk position with and without reduction. The intraobserver agreement was high for all three techniques. The interobserver agreement of the seven observers when the disk position was diagnosed by fluoroscopy in combination with lateral transcranial radiography (Kappa index 0.68) was higher than that with fluoroscopy alone (Kappa index 0.54) and that with fluoroscopy in combination with corrected sagittal tomography (Kappa index 0.56). The sensitivity, specificity, and predictive values of fluoroscopy in combination with lateral transcranial radiography were also higher than those of the other radiographic techniques. Judged from this study, the observer agreement and the diagnostic outcome for arthrography with the use of the three examined techniques are high when well-defined criteria and reference images are applied.

Thirty-five patients each with a tentative diagnosis of osteomyelitis of the mandible were examined with 99Tcm-labeled phosphorus compounds. The scintigraphic findings were compared with the radiographic features and related to disease stages to evaluate the diagnostic potential of bone scintigraphy in different disease stages. The scintigraphy was valuable to exclude bone tissue involvement in some patients with clinical signs and symptoms similar to those of osteomyelitis and with equivocal radiographic findings. In 13 patients with chronic osteomyelitis, scintigraphy revealed a larger extent of the lesion than the radiography. In lesions with permeated bone destructions with penetration of the cortex, the uptake of 99Tcm was higher than in lesions with a motheaten or sclerotic appearance. This study supports the view that 99Tcm-bone scintigraphy is a useful tool at various stages of osteomyelitis, that is, in its early detection, in the treatment or biopsy planning, and in the evaluation of the efficacy of treatment.

The absorbed doses and energy imparted for the Orthopantomograph model OP 5 using two different collimators (0.9-1.3 X 33 mm2 and 0.6-0.9 X 39.5 mm2, respectively) were examined at 70 and 75 kV. The absorbed doses were estimated by thermoluminescence dosimetry in a sectioned phantom and by the energy imparted from measurements of areal exposure using a plane parallel transmission ionization chamber. The exposure distribution was surveyed on radiographic film. The anterior part of the parotid glands received the highest absorbed doses (2.4-3.2 mGy) when the wider collimator was used, with a decrease of two to three times when the narrower collimator was used. Other areas received absorbed doses of about 1.0 to 1.5 mGy or below. An increase of the kV from 70 to 75 had a minor influence. The energy imparted for the wider collimator was 0.6-0.8 and for the narrower collimator, 0.4-0.6 mJ.

In 127 temporomandibular joint autopsy specimens the position (superior 44%, partially anterior 22%, completely anterior 34%) and configuration of the disk (biconcave 56%, biconvex 10%, others 34%) were related to osteoarthrosis. All biconvex disks were positioned anteriorly and associated with osteoarthrosis. Biconcave disks were mostly positioned superiorly and associated with normal surfaces.