Abstract: Objective: To analyze the visualization consistency of mandibular canal on panoramic images and CBCT images, and to discuss the non-pathological factors influencing the visualization of mandibular canal. Methods: Using digital panoramic images and cone-beam computerized tomography images from 92 patients shooting in Hospital of Stomatology, Sichuan University during December 2013 to February 2014 and these images were evaluated by two radiologists. The mandibular canal was divided into 3 equal width areas from mental foramen to anterior border of ramus. The visibility of the mandibular canal borders was assessed using 4 point visibility scoring system, with lower scores for worse visibility. Results: The internal consistency inspection of two doctors conformed to the standard. In CBCT, average score of area 1 was 2.120, area 2 was 2.337, and area 3 was 2.533. In panoramic average, score of area 1 was 1.772, area 2 was 1.973, and area 3 was 2.207. Conclusion: CBCT remarkably improve the visualization of the mandibular canal in the area 1. The visualization of the mandibular canal in CBCT is significantly higher than in panoramic, while only 1％ of the mandibular canal in panoramic is visible and is invisible in CBCT. There is a close correlation between age and visualization, and the visualization gets poor with age.

Key words: Cone-beam computerized tomography , Digital panoramic radiographs, Mandibular canal, Visualization