Position of Mandibular Canal in Cross-sectional Computed Tomographs

The importance of position of mandibular canal (MC) has been recognized when endodontic, surgery and implant treatment are contemplated. Previous studies investigated position of MC in superior-inferior dimension and found variation. Panoramic radiographs can present an inaccurate position in superior-inferior dimension. The object situating more lingually will be projected to a higher position than the one situating more bucally because of the slightly upward projecting beam of the machine. The variation of MC position might be due to the race. Objectives: to assess position of MC in superior-inferior and buccal-lingual dimensions in a group of Thais. Methods: Fifty Thai patients were consecutively selected from computed tomography files. Cross-sectional images were reformatted in areas of mesial roots of #47, #46, #36 and #37, and roots of #45 and #35. MC were assessed and allocated into one of the 9 areas such as buccal-superior, buccal-middle, buccal-inferior, middle-superior, middle-middle, middle-inferior, lingual-superior, lingual-middle and lingual-inferior. Thirty randomly selected images were assessed a second time to investigate allocating precision and presented as kappa value. Results: Twenty-eight females and 22 males were included. Average age was 45 years with range of 16 to 77 years. Total 237 images comprised 42 #47, 38 #46, 41 #45, 45 #35, 30 #36 and 41 #37. Kappa value was 0.69. Ninety %, 55%, 83% and 89% of images on areas #47, 46, 36 and 37, respectively, showed MC locating in lingual third of mandible. Forty-eight % and 53% of images on areas #45 and #35 revealed MC situating in buccal third of mandible. Seventy-nine to ninety-six % of images showed MC present in middle or inferior third of mandible. Conclusions: Mandibular canal ran from buccal aspect of mandible in second premolar area to lingual third of mandible in molar area and mostly located in middle or inferior third of mandible.