Accuracy evaluation of panoramic radiography in detecting the position of third molar roots

Correct radiographic interpretation, especially for root morphology is a useful way to choose open or close surgery and to avoid root fracture during tooth extraction. Since, the third molar has the most irregular and unpredictable root position between all teeth, this study was performed to evaluate the accuracy of panoramic radiography in detecting the position of third molar roots. This cross-sectional and analytical study was performed on 38 patients [49 third molar teeth] who referred to Babol dental school during 2003-2005. Panoramic radiographs were taken from patients in the standard condition and two specialists of oral and maxillofacial radiology and surgery were asked to complete the questionnaire about radiographic interpretation of third molar before surgery. The questionnaire contained the number of tooth roots, relation between roots and relation between root angle and crown. After surgery tooth position was evaluated again. Presurgical and post-surgical radiographic findings were compared and then data were analyzed using paired t-test, X [2], Linear regression and Pearson correlation coefficient. In this study, the accuracy of interpretation of panoramic radiographs in evaluation of number of third molar roots and relation between roots [fused or non fused] was 64.3% and 63.3%, respectively. For the root angle to crown, the radiographic interpretation significantly estimated accurate angle [p<0.0001]. According to the results, panoramic radiography is a useful method for evaluation of the third molar position. Nevertheless, we must be aware of its high diagnostic error rate in evaluation of morphological details of root [number of roots and relation between roots]