多機能断層撮影 (Scanora^®) による歯間部および根分岐部の歯槽骨欠損の検出能

抄録

The diagnostic accuracy of multimodal tomography (Scanora^®: SCA) was compared with that of digital radiography (Digora^®: DIG) for periodontal intrabony defect and bifurcation involvement. Five dry mandibular jaw specimens were used. Eight proximal molar sites and eight furcation sites were selected in this study. Simulated lesions were created at the interproximal intrabony and the inter-radicular regions by removal of bone with the use of round burs that measured 0.8mm in diameter. Six interproximal and six bifurcation lesion stages were created with depths of 2mm and widths of 0mm, 1mm, 2mm and 3mm measured with a periodontal probe. Tangential tomograms were taken with a Scanora^®. Periapical radiographs were obtained by the paralleling technique (60kV, 40cm FSD). Exposure was adjusted to speed-E periapical film. These images, randomized in sequence, were assessed by six observers. In Digora^®, the contrast and brightness fitness could be adjusted by the observer. The effectiveness of each technique in detecting lesions and identifying normal cases was measured by calculating the percentages of lesions detected (sensitivity) and the percentages of normal cases identified (specificity). Mean sensitivity/specificity for the intrabony area were 0.76/0.88 (SCA), 0.82/0.90 (DIG), and for the bifurcation area were 0.45/0.84 (SCA), 0.31/0.74 (DIG). According to the results, the Scanora^® had better performance in detecting bifurcation defects than the Digora^®. These results suggest that: (1) multimodal tomography is as good as intraoral radiograpy in the diagnosis of intrabony defects; and (2) in detecitng bifurcation defects, multimodal tomography is more useful than intraoral radiography.