A Study On Mandibular Canal Anatomy By CBCT Of Han,Dai And Hani People In Yunnan Province

Objectives:Core Bean Computed Tomography(CBCT)was used to scan the mandibles of the Han,Dai and Hani populations in Yunnan,and the mandibular canal courses and adjacent tissues were quantified on the 3D reconstructed image of the mandible.The relationship between the location of mandible canal of different nationalities,different ages and different genders provides a clinical reference for stomatologists to perform diagnosis and treatment in the mandibular canal courses.Methods:According to the inclusion and exclusion criteria,the random number method was used to collect the CBCT image data of the Department of Oral Imaging in Yunnan Provincial Stomatological Hospital,Jinghong people's Hospital and Honghe people's Hospital from February 2018 to February 2020,Grouped by different ethnicities,ages and gender.A total of 339 cases of CBCT image data were collected according to the inclusion and exclusion criteria,among them,there were 113 people each in the Han,Dai and Hani groups;122 in the youth group,127 in the middle age group,and 90 in the elderly group;182 men and 157 women.The coronal plane of the mandible was used to observe the mandibular canal,The distance between mandibular canal and alveolar ridge crest,lateral wall of the cortical bone of the inferior margin of the mandible,the buccal bone plate and the lingual bone plate lateral cortical wall and the root apex.Statistical analysis by spss 22.0 software package.Results:1.The location of the mental foramen:The location of the mental foramen were similar in ethnic,age and gender,and the position with the highest rate was between the root of the first and second premolars of the mandible,The second was the root of the second premolars,and the proportion between the root of the first premolars and the second premolars was the smallest.2.Vertical position of the mandibular canal:The distance from the superior margin of the mental foramen and the inner margin of superior wall of mandibular canal to the alveolar ridge was statistically significant differences in terms of ethnicity,age and sex(P<0.05).The distance from the inner margin of the inferior wall of the mandibular canal to the lateral wall of the cortical bone of the inferior margin of the mandible was statistically different in ethnicity and age(P<0.05),but there was no statistically significant difference in sex(P>0.05).3.The position of the mandibular canal in the buccal and lingual directions:There were statistically significant differences in ethnicity,age and sex about the distances from the mandibular canal to the buccal bone plate and the lingual bone plate lateral cortical wall(P<0.05).4.Relationship between the mandibular canal and the root apex:There were statistically significant differences in ethnicity,age and sex about the distances from the inner margin of superior wall of mandibular canal to the root apex(P<0.05).Conclusions:1.The position of the mental foramen with the highest rate was between the root of the first and second premolars of the mandible.When performing immediate implantation in the mandibular premolar area,the location of the mental foramen should be carefully observed to avoid nerve damage during surgery.2.There were statistically significant differences in ethnic,age and sex in three-dimensional position of the mandible.In the clinical diagnosis and treatment of the posterior teeth area,the position of the mandibular canal estimate can be predict by the patient's ethnicity,gender and age characteristics.3.The three-dimensional position of the mandibular canal in the mandible can be clearly observe by using CBCT and NNT software,which has great clinical guidance and reference value for the formulation of mandibular surgery and implantation.