Research Of Anatomic Characteristics Of Lingual Foramina In The Mandibular Complete Edentulism By Cone-Beam Computed Tomography

Objective:Use cone-beam computed tomography(CBCT)to observe the lingual foramina(LF)and lingual canal(LC)of patients with mandibular complete edentulism to understand its anatomical characteristics such as anatomical position,number,distribution,foramina diameter and canal length.To prevent risks for the design of mandibular anterior tooth implant surgery,in order to reduce the occurrence of intraoperative and postoperative complications and improve the success rate of surgery.Methods:Retrospective study.Select the CBCT image data of 70 patients with mandibular dentition deficiency type III alveolar bone resorption who were treated in Dalian Stomatological Hospital from January 2017 to June 2018 were aged 65-80 years.Observe the detection number of LF in the interforaminal region and the frequency,distribution,diameter,distance from the alveolar dome/submandibular plane,and the length,direction and termination of the LC were observed and measured.The patients were divided into male group and female group according to gender,and the differences in anatomical characteristics of LF with type III alveolar bone resorption of different genders were analyzed.Statistical analysis was performed on the data using spss20.0 software.The measurement results of the anatomical characteristics of the LF and LC were described by the mean±standard deviation,and using t test statistically analyze the differences in anatomical characteristics between different genders were.P value<0.05 was considered to be statistically significant.Results:By observing the CBCT images of the 70 patients,a total of 246 LF were found.Each patient found LF in the interforaminal region,and the number of LF in the anterior interforaminal region was 2-6.According to their position distribution,they can be divided into median lingual foramina(MLF 31-41)and lateral lingual foramina(LLF 32-35,42-45).The MLF accounted for 52.4%of the total.All patients had MLF.Among them,more than half of the patients had 2 MLF,most of which consisted of 1 suprasacral spine foramina and 1 inferior sacrospinous foramina.Two patients do not have LLF and single sample could have up to three LLF.The diameter of the MLF is between 0.25mm and 1.41mm,with an average value of 0.62±0.28mm.Among the suprasacral,intersacral,and subsacral foramina,the diameter of the suprasacral spine foramina is the largest and the intersacral spine foramina is the smallest.The diameter of the LLF is between 0.22 and 1.47 mm,and the average value is 0.61 ± 0.26mm.It is about the same size as the MLF.For the distance(AC1)from the upper edge of the LF to the alveolar crest,the average height of the median tongue hole was 5.81±3.04 mm.The AC1 values of the suprasacral,intersacral and subsacral holes differ.Correspondingly,the minimum distance(BC2)between the lower edge of the MLF and the plane of the lower jaw is 1.60 mm and the maximum is 13.81 mm The BC2 value of the LF in the premolar area is slightly smaller than that in the lateral incisor and canine area.In terms of gender differences,the diameter of the MLF and LLF is larger in men than in women.In the three divisions of the LLF,the premolar area,the diameter of LF male>female having statistical significance.The distance between the lower edge of the tLF and the plane of the lower edge of the mandible was statistically different from that of the suprasacral spine foramina in the median area(men were higher than women).In this study,the incidence of with a diameter?1mm was 13.4%(33/246).Patients with larger LF accounted for 37.1%of the total number of patients.There are 19 large(14.7%)MLF,mainly distributed on the suprasacral spine area.Among the lateral area,there are LLF in the lateral incisor,canine and premolar areas,respectively,with incidences of 14.3%,13.8%and 10.0%.The average length of the LF was 5.99 ±1.76mm,and the blind end mostly stopped in 1/3 of the mandible.54.1%of the LF and the incisor canal converged.Most of the suprasacral foramina go down,while most of the subsacral foramina run horizontally.There is no significant difference in the direction of the LLF.Conlusion:The LF is more common in the anterior interforaminal region,especially in the median region,and there are several foramina coexisting.It is best to perform CBCT imaging before anterior implantation.The LF differs in gender,and a complete and detailed preoperative examination and surgical plan are more needed when performing surgery on male patients.This study provides some theoretical basis for patients with mandibular dentition missing to perform implant surgery in this area for reference.