A study by Bell, et al assessed the accuracy of panoramic radiography in preoperatively predicting mandibular third molar root configuration and proximity of roots to the mandibular canal. The study involved 219 patients for whom 300 third molar extractions were planned. The qualitative endpoints of preoperative evaluation of the radiographs were the type of impaction; number of roots; presence or absence of root fusion; presence, direction, and magnitude of root curvature; and the relationship of roots to the mandibular canal. During surgery the extraction socket was examined to assess the relationship between the tooth and the mancibular canal, and postoperatively, tooth fragments were reunited with glue, and the angle of root curvature, length of each root, and width of the last 2 mm of curvatures were measured. The study found that panoramic radiography is not sensitive for detection of mandibular molar root curvature and for close association of roots to the mandibular canal. Panoramic radiography does reveal certain preoperative information not assessed by this study, such as root length and tooth inclination.
(Source: Journal of Evidence-Based Dental Practice, Vol. 3, No. 4, 2003)