Accuracy of extraoral bite-wing radiography in detecting proximal caries and crestal bone loss

Background Extraoral bite-wing (EB) radiography is an imaging technology used in dentistry. The authors conducted an in vivo study comparing the accuracy of intraoral bitewing (IB) radiographs and EB radiographs for proximal caries and bone loss diagnosis. Methods The authors recruited 116 patients who received IB radiographs to receive EB radiographs. The 5 calibrated authors made a consensus radiographic diagnosis of proximal caries and crestal bone loss. For this study, they assumed IB radiographs as the criterion standard. Next, they obtained EB radiographs for the 116 patients and calculated sensitivity, specificity, and false-positive rates against each patient's IB radiograph. Results The patients’ EB radiographs revealed a significantly greater number of caries and crestal bone loss findings compared with their IB radiographs. The EB radiographs had a high to excellent sensitivity and moderate to low specificity of caries and crestal bone loss findings, respectively. Considering IB radiographs to be the criterion standard, the false-positive rate for EB radiographs was moderate for caries and high for bone loss diagnosis. Conclusions The EB radiographs, which generate fewer images of overlapping proximal surfaces, have the advantage of detecting more carious lesions and bone loss findings than the IB radiographs do, but with the disadvantage of more false-positive diagnoses. Further research is needed to evaluate if the false-positive findings represent true carious lesions and bone loss. Practical Implications EB radiography is a promising technology, which has several advantages over traditional IB radiography. Clinicians should be aware of false-positive diagnosis of caries and bone loss with EB radiography.