To Measurement And Clinical Significance Of Inferior Alveolar Nerve Canal Using Cone Bome CT

Objective: The position of the lower alveolar nerve canal in the mandibular body And the position of the apex of the mandibular posterior teeth was observed by cone beam CT(CBCT).The imaging data were provided for the alveolar surgery,especially the third molar removal and the mandibular molar implantation,and the tooth extraction and implantation Resulting in the probability of alveolar nerve injury.Methods: 1?Collected from November 2013 to November 2015 in Zunyi Medical College Affiliated Hospital of patients with mandibular CBCT images.Requirements of the image including mandibular third molar,including the absence of mandibular teeth,no mandibular tumor,fractures and other factors affecting the measurement.After selecting,there were 100 cases(including 55 males and 45 females,aged 20-55 years).import the images into NNT2.0 software.2?After reconstructing the images,the bilateral mandibular second molar,the first molar,the second molar,the third molar,the Alveolar crest midpoint between mandibular second molar and the first premolar,the Alveolar crest midpoint between second premolar and the first premolar,(6 point)as the measurement point;observe the shape of the mental hole.3?The distance between the lowest point of the root tip of the tooth tip and the outer wall of the alveolar nerve cancal(L1),the distance from the outer wall of the inferior alveolar nerve canal from the buccal bone(L2),the distance from the outer wall of the inferior alveolar nerve canal from the lingual side plate(L3),the distance from the outer wall of the inferior alveolar nerve canal from the lower edge of the mandible(L5),the vertical inferior alveolar nerve canal to the inner diameter(d)was measured at the mandibular second molar,the first molar,the second molar and the third molar.At the Alveolar crest midpoint of the mandibular second molar and the first premolar,the Alveolar crest midpoint of the second molar and the first premolar was increaseed measurement the distance between the outer wall of the alveolar nerve canal and the Alveolar crest(L4).4?Using the second premolar,the first molar,the second molar and the third molar four measurement sites at the lowest point of the root tip and the lower alveolar nerve canal wall distance(DTC)to :DTC <2 mm,2 mm ? DTC <6 mm,DTC ? mm for type.5?the results of the use of SPSS 19.0 software for statistical analysis.Results: A total of 100 patients were measured with CBCT images,and 1200 were measured,and 200 inferior alveolar neural canal were observed.1?the measurement process found 1 case of double-type alveolar nerve canal and 1 case of sub-hole.2?the shape of the Mental hole is 32% round and 68% oval,The diameter of the inferior alveolar nerve canal was significantly changed from the front to the rear,with an average diameter of 2.1 mm-2.71 mm and no difference between men and women.The lower alveolar nerve canal in the mandibular first molar for the vertical to the lowest point of travel.And the lower alveolar nerve tube to the first molar as the center,the proximal and distal segments are close to the alveolar crest,and far from the middle of the increase is greater than the middle.The most of the lower alveolar nerve canal in the mandibular second molar and the first molar between the alveolar ridge at the middle of the mandibular buccal lateral side of the tongue from the side of the transition.And the point as the center,the middle of the lower jaw side of the line,far from the middle of the mandibular side of the tongue and the mandibular side of the bone plate between the distance gradually smaller.There were significant differences between men and women,and men were greater than women.4?According to the measurement of the distance between the apical point of the mandibular posterior teeth and the distance between the inferior alveolar nerve canal(DTC),the relationship between the root tip and the inferior alveolar nerve canal was divided into the following: the occurrence rate of type?(DTC <2 mm)was 25%;the occurrence rate of type?(2 mm ? DTC<6 mm)was 48.8%.The occurrence rate of type ?(DTC?6 mm)was 26.3%.There was no significant difference between male and female.Conclusion: The relationship between the apical and inferior alveolar neural canal that type?was the lowest frequency,However,the proportion of the third molar and the second molar was higher in the tooth sites that affected class I relationship.Therefore,Suggesting that clinicians in the posterior area of the hole after implantation surgery and alveolar surgery before the need for accurate preoperative assessment.