ABSTRACT
Accurate radiographic assessment is a must in cases of impacted lower third molars with proximity to mandibular canal to avoid the high risk of neurovascular bundle injury during surgical removal. This study was conducted as an attempt to assess the relation of horizontally impacted lower third molar to mandibular canal using curved tomography [panoramic radiography] and spiral CT scanning. Fifteen patients were comprised in this study. They were all suffering from horizontally impacted lower third molar. Images of both modalities were qualitatively and quantitatively analyzed to reveal relation of the molar to the canal. Out of our results: [1] The most common radiographic features strongly linked to intimate relation [40% of the cases] and highly predicting of contact between horizontally impacted lower third molar and canal are: superimposition of roots on canal and presence of roots just touching the superior border of the canal. [2] Majority of the investigated teeth were not in contact with the canal [60%]. The mandibular canal was most often inferior or buccal or inferiobuccaly to the roots of the horizontally impacted lower third molars. It could be concluded from this study that whenever one of the radiographic criteria predicting close proximity of molar to canal is evident on panoramic radiograph, CT should be performed to clear out the exact location of the canal. Spiral CT allows faster scanning, more resolution and a high degree of accuracy when planning removal of third molar in proximity to the canal, making it possible to formulate a more precise diagnosis and treatment plan