A Cone-beam CT Study On The Anatomical Position Of Accessory Mandibular Foramina In Jiangxi Adults

Purpose This study used cone-beam computed tomography to access the anatomical position and distribution of accessory mandibular foramina(AF) in the mandibular body of Jiangxi adults,and analyzed the effect factors of age, gender and lateral on AF, to give some safety rules of operation for clinics.Materials and methods 200 CBCT image subjects scanned by radiology department of Stomatological Hospital Affiliated to Nanchang University were selected in accordance with standards from 2014 to 2015, which were divided into 4 groups by age(20~29Y, 30~39Y, 40~49Y, 50 Y and above) with the same sex ratio. After the CBCT image subjects were imported into Mimics 17.0 software, 2 researchers observed AF and landmarks and recorded their 3D coordinate values. Define menton as the origin, mandibular plane as X-Y axis plane and median plane as Y-Z axis plane, and then a new three-dimensional coordinate system was established and new 3D coordinate values of AF were calculated by vector algorithm. The number and position of AF were described and the relationship between AF incidence and factors of age, gender and lateral were analyzed.Results 200 subjects demonstrated 1123 accessory foramina,and the number of AF ranged from 1 to 12 and the average was 5.63(SD 2.10) in an individual. The highest regional frequency of foramina was recognized in the mandibular symphysis area(98.0%), followed by lingual anterior teeth areas(left 85.5%, right 85.0%), and the lowest regional AF incidence was buccal molar areas(5.5%), in addition, accessory mental foramina incidence was 9.5%. Lingual AF incidence was higher than the buccal. There was no significant difference in the number of subjects presenting with AF in left and right area(P>0.05), and the same in man and woman(P=0.195). Meanwhile, the different age groups shown significant difference in the distribution number of AF(P<0.01), and the number of AF was negatively correlated with age(rs=-0.301). Three AF concentration areas were mandibular symphysis area, lingual alveolar area of lower medial and lateral incisors and inferior area of lingual premolar region. The latter two incidences were 88.0% and 55.0%. Their mean vertical distances to mandibular plane were 8.21 mm, 26.45 mm and 3.05 mm, and their mean diameters were 0.85 mm, 0.81 mm and 0.88 mm.Conclusion AF were widely presented in the body of everyone's mandible, and the three highest frequency regions of foramina were mandibular symphysis area, lingual alveolar area of lower medial and lateral incisors and inferior area of lingual premolar region. Addition attention should be paid to avoid the complications causing by the damage of accessory canal contents in the clinics. Mandible nutrition was not only supplied by inferior alveolar artery, but presented multi-sources.