Measurement And Analysis Of Mandibular Canal Course By Cone-beam Computed Tomography

Objective: To measure the distance from the mandibular canal to the buccal surface,lingual surface,alveolar ridge crest and the lower of the mandible.Juge the course of the mandibular canal in mandibular posterior area by cone-beam computed tomography(CBCT),to provide a theoretical support for implant preoperative assessment.Methods:65 patients were selectd,which treated in the oral medical center of Anhui Provincial Hospital between July 2014 to June 2015.Which contained 35 males and 30 females.The age between 21 to 67 years,the mean age was 43 ± 2.3 years.All the CBCT imaging data of the patients was taked by the same radiologists,which has extensive experience.The CBCT scanning voltage was 90 k V,current 9 m A,recording time: 21 s.Measuring method: according to the tomographic image at the upper side,intercepting the image of the mental foramen,mental foramen after 6mm,mental foramen after 12 mm,and mental foramen after 18 mm.A total of four positions was the measurement section.Measurement content: The horizontal distance from the mandibular canal to the buccal surface.The horizontal distance from the mandibular canal to the lingual surface.The vertical distance from the mandibular canal to the alveolar ridge crest.The vertical distance from the mandibular canal to the lower of the mandible.Each measurement items measured by three times,and calculate the average data.Results: The horizontal distance from the mandibular canal to the buccal surface gradually increasing from front to back,at a minimum in the mental foramen,at a maximum in the mental foramen after 18 mm.The horizontal distance from the mandibular canal to the lingual surface gradually reduced from front to back,at a maximum in the mental foramen,at a minimum in the mental foramen after 18 mm.The vertical distance from the mandibular canal to the alveolar ridge crest gradually reduced from front to back,at a maximum in the mental foramen,at a minimum in the mental foramen after 18 mm.The vertical distance from the mandibular canal to the lower of the mandible decreases before,and then increase,at a minimum in the mental foramen after 6mm,at a maximum in the mental foramen after 18 mm.All the results has no significant statistical differences between the male and the female(p>0.05),and has no significant difference between the left and the right sides(p>0.05).Conclusions: 1.The CBCT can accurately measure the position and the course of the mandibular canal,and the relationship with the surrounding tissue.2.The average distance of mandibular canal outer edge to the buccal bone plate by former backward increased gradually.The average distance between mandibular canal in ner edge to lingual bone plate by former backward reduced gradually.The average dista nce between mandibular canal upper edge to alveolar crest by former backward reduced gradually.The average distance between the edge of mandibular canal to the edge of ma ndible by former backward reduced previous,then increased.