A comparative study of internal fixation and intermaxillary fixation on bone repair of mandibular fractures through radiographic subtraction

Reproducibility of subtraction radiography in monitoring changes in approximal carious lesions in children: An in vivo study

BACKGROUND

Laboratory studies have shown that digital subtraction radiography (DSR) can be a more effective tool, than conventional radiography, in monitoring changes in carious lesions. The clinical performance of the technique, however, has not been sufficiently researched.

AIM

To compare the reproducibility of DSR to that of bitewing radiographs, in monitoring changes in approximal caries in the mixed dentition. A secondary aim was to determine whether assessment outcomes differed as a function of the method used.

DESIGN

Six assessors evaluated 310 lesions first on bitewings, then with DSR. The overall reproducibility was evaluated via intra-class correlation coefficient (ICC). Intra- and inter-rater reproducibility were assessed using weighted Kappa. Paired t test was used to assess differences in the reproducibility across methods.

RESULTS

The overall reproducibility for DSR was (ICC = 0.47, 95% CI = 0.31-0.56). Intra- and inter-rater reproducibility were 0.65 and 0.44, respectively. The overall reproducibility for bitewings was ICC = 0.45, 95% CI = 0.42-0.57. Intra- and Inter-rater reproducibility were 0.71 and 0.46, respectively. Differences in the reproducibility across methods were not statistically significant. Significantly more lesions were scored as progressed using DSR.

CONCLUSIONS

The reproducibility of DSR in monitoring changes in approximal caries is comparable to that of bitewings. Additionally, DSR detected higher proportion of progression than bitewing assessments.

Accuracy of Digital Subtraction Radiography in the Detection of Vertical Root Fractures

INTRODUCTION

The objective of this study was to evaluate the accuracy of digital subtraction radiography in the diagnosis of vertical root fractures (VRFs).

METHODS

Twenty decoronated uniradicular human teeth were placed in the alveoli of a dry mandible and radiographed twice, first without (unfilled roots) and then with (filled roots) a gutta-percha cone placed into the root canal. Roots were then removed from the dry mandible, and vertical fractures were created with the aid of a universal testing machine. The fractured roots were repositioned in the mandibular alveoli and again radiographed twice. Radiographic images were subtracted by using the Regeemy software in 3 test situations: group 1, initial radiographic images of unfilled roots and images of fractured or non-fractured unfilled roots; group 2, initial radiographic images of unfilled roots and images of fractured or non-fractured filled roots; and group 3, initial radiographic images of filled roots and images of fractured or non-fractured filled roots. Three examiners evaluated all the original digital radiographs, as well as the subtracted images, for the presence or absence of VRFs. Numerical data were subject to statistical analysis with the use of receiver operator characteristic (ROC) curves.

RESULTS

The areas under the ROC curve for groups 1, 2, and 3 were 0.86, 0.73, and 0.66, respectively. For the original digital radiographs, areas under the ROC curve were 0.80 (without gutta-percha) and 0.73 (with gutta-percha). No statistically significant differences were found between subtracted and original images.

CONCLUSIONS

Digital subtraction radiography could be considered as an alternative tool for the investigation of VRFs because of its comparable diagnostic accuracy to existing methods.