Detection of experimentally induced root fractures on digital and conventional radiographs: an in vitro study

This study compared the diagnostic accuracy of digital radiographic images with conventional radiographs for the detection of experimentally induced root fractures. Horizontal fractures were induced by a mechanical force to the root of 15 single rooted teeth. Vertical fractures were induced in 15 single rooted teeth and 15 molars, respectively, by disk cutting. The teeth were mounted in dried mandibles and were radiographed with the parallel technique using a CCD-based Planmeca imaging system and F-speed films. Seven observers recorded their findings and then 2 pairs of them examined the same images together. Az values expressed the diagnostic accuracy of the imaging systems and the degree of agreement was estimated using the Cohen's kappa statistic. The areas under the ROC curves (Az) in single rooted teeth were 0.61 for conventional radiography and 0.64 for digital radiography. Digital imaging system did not perform significantly better than conventional one (p > 0.01). Digital radiographs (Az: 0.72) provided higher detection accuracy in molars than conventional images (Az: 0.51) (p = 0.0102). The digital images scored higher kappa values with narrower range than conventional. Observers in pairs did not perform significantly better than individually. The results were not affected by the observers but were affected by the cases (p < 0.001). Digital images were equivalent to F-speed films for the detection of root fractures in single rooted teeth. The digital system performed significantly better than the conventional in detecting root fractures in molars.