Marginal bone level buccal to mandibular molars in digital radiographs from charge-coupled device and storage phosphor systems. An in vitro study.

The aim of this in vitro study was to compare bone loss measurements in the furcation area of mandibular molars in digital radiographs from a CCD-(Sens-A-Ray) and a storage phosphor (Digora) system, 10 1st and 7 2nd mandibular molars, with intact lingual but reduced buccal bone with furcation involvements, were used. Radiographs were first taken with lead markers at the most apical part of the buccal bone and at the cemento-enamel junction. These radiographs were used to establish a radiographically true distance between the CEJ and the buccal bone level. The lead marker at the CEJ served as a reference point for the observers' subsequent estimates of the extent of bone removed, which were made in radiographs without lead markers at the bone level. 1 exposure (400 ms) for the CCD- and 5 (160 ms, 200 ms, 250 ms, 320 ms, 400 ms) for the storage phosphor system were used. Measurements were made in unprocessed (original) and processed images (contrast enhanced and/or high pass filtered). The results showed underestimation of bone loss, but smaller than previously reported for film radiographs. No significant difference was found between the 2 systems when compared at the same exposure. Nor were any significant differences found between unprocessed and processed images or between storage phosphor images from different exposures. We conclude that digital radiographs are comparable to film based radiographs for measurement of buccal bone loss but that lower exposures can be used, especially with the storage phosphor system.