Objectivity and reliability of panoramic radiographic signs of intimate relationship between impacted mandibular third molar and inferior alveolar nerve.

Abstract

The results of prior studies assessing the accuracy of panoramic radiographic signs of intimate relationship between inferior alveolar nerve (IAN) and impacted molars are controversial. This may be partly due to inadequate objectivity and reliability of these radiographic signs, which is evaluated in the present study. Three hundred radiographs in which impacted third molar reached the superior border of the inferior alveolar canal or was superimposed by the canal were evaluated by three examiners independently, twice 3months apart. Inter- and intra-examiner agreements were analyzed using kappa statistics. The inter-examiner agreement for all radiographic signs was poor (k < 0.2). The intra-examiner agreement for radiographic signs 2, 3, and 6 was poor with mean kappa values of 0.08, 0.00, and 0.09, respectively. Concerning the radiographic signs 4, 5, 7, and 8, the intra-examiner agreement was moderate with mean kappa values of 0.54, 0.49, 0.44, and 0.57, respectively. The mean kappa coefficient for the radiographic sign 1 yielded a good agreement (k = 0.65). In the present study, the examiners were unable to reliably assess radiographic signs of intimate relationship between IAN and third molar, indicating that panoramic images should not be relied upon for preoperative prediction of IAN injury.