This study aimed to evaluate more deeply the association between impacted lower third molar and inferior alveolar canal based on radiographic signals suggesting proximity of structures and the PG, Winter and Alling and Alling classification, to increase the information that will be gather from panoramic radiograph. All the impacted mandibular third molar included in this study were evaluated for type of angulation, depth of impaction, available space and relation of their root with inferior alveolar canal on the basis of panoramic radiographic presentation.