Imaging Study Of The Retromolar Canal Of Adult Mandibular Based On CBCT

Objective To investigate the incidence of bifid mandibular canal of adult by cone beam computed tomography(CBCT),summarize the types,morphological characteristics and measure the distance between points of the retromolar canals,so as to provide data support reference for clinical surgery.Methods The clinical data of 500 patients undergoing CBCT were collected from the Department of Radiology,Guiyang Stomatological Hospital from 2017 to2019,which were screened strictly according to the inclusion criteria to observe the number,types,proportion of bifid mandibular canals,as well as the morphological features and existing types of retromolar canals.Results 1.A total of 445 cases(890sides)were brought to this study,of which 264 patients(364sides)were found,including 147 sides of dental canal(16.52%),118 sides of forward canal(13.26%),and 99 sides of retromolar canal(11.12%),not any buccolingual canal was founded.2.99 sides of retromolar canal in 90 patients were founded in all,including 44 males(46sides)and 46 females(53sides),36 in left sides and 63 sides in right,there was no significant difference between genders,but right canal was significantly more than left canal(P<0.05).Retromolar canal was divided into type Ⅰ to type Ⅷ according to its shape and trend.Type Ⅱ was the most common reaching 50 sides(50.51%),followed by type Ⅰ with 23 sides(23.23%),the rarest type Ⅵ only got one side(1.01%).3.The average vertical height and horizontal length of the retromolar canal were 10.39±2.47 mm and 11.93±3.03 mm respectively.The average distance from retromolar canal to distant cemento-enamel junction of second or third molar was(11.55±5.37)mm.The average starting diameter and outlet diameter of retromolar canal were 1.75±0.77 mm and 1.26±0.51 mm.Starting diameter significantly wider than that of the outlet diameter(P<0.05).4.51 people were found to have 55 sides of retromolar foramen in 445 patients,including 27 males and 24 females;21 sides onthe left side and 34 sides on the right side,with no statistical difference in gender and sides distribution(P>0.05).Conclusion Retromolar canal real not a rare anatomical structure.CBCT before operation is of great significance to evaluate the mandibular canal branches and the morphology of retromolar canals which to help avoid surgical risks and develop a safer surgical plan.