Radiological Study Of Mandibular Anatomical Structures Critical For Dental Implant Appllcations

Objectives To provide reliable anatomy data for mandibular implant surgery by virtue of imaging studies of anatomical structures related to implant placement.Methods The mandible CBCT scan images from 100 Chinese patients who was planning to receive implant supported restoration in the department of stomatology were selected.Among the 100 cases,55 cases are male and 45 cases are females.According to the measure of occlusal condition analyzing the data as below:(1)The percentage of mental foramen and lateral lingual foramina's relative position of mandibular.(2)The position relation and the distance of mental foramen and accessory mental foramen.(3)The vertical and horizontal diameters of the mental foramen.(4)The diameter of the accessory mental foramen.(5)The distance from the alveolar ridge to mental foramen.(6)The diameter of the lateral lingual foramina.(7)The length of the lateral lingual canal.(8)The distance from the alveolar ridge and lower margin of mandible to the lateral lingual canal.(9)The angle between the lateral lingual canal and the lingual bone plate.(10)The length of the anterior loop.(11)The percentage of the median lingual foramen.(12)The length and diameter of the lingual canal in mandibular anterior region.(13)The distance from buccal-lingual bone plate,alveolar ridge crest and inferior border of mandible to the origin of the lateral lingual canal in anterior teeth.(14)The angle between the median lingual canal and the horizontal plane.(15)The position of incisor canal.(16)The diameter of incisor tube perpendicular and buccolingual direction.(17)The length of the incisive canal.(18)The distance from incisive canal to the origin of mandible.Results There were statistical significance as follows: the mental foramen is most located in the second premolar(56%),then exists between the first and second mandibular premolars(33%).The average horizontal size of mental foramen with dentulous jaws is 3.00±0.73 mm.The vertical dimension is 2.94±0.87 mm.The average vertical distance of mental foramen and alveolar ridge of the patients with edentulous jaws is 13.83±2.52 mm.The average vertical distance of mental foramen in edentulous patient and alveolar ridge crest is 12.20±3.02 mm.The distances of mental foramen and alveolar ridge crest for the patients with or without edentulous jaw have statistical significance(P<0.05).It was observed that the average distance between the accessory mental foramen and the mental foramen is 3.92±2.18 mm for the edentulous patients and 3.55±1.86 mm for the patients without edentulous jaw in 12% cases.In 80%cases,there was AL,the maximum length of AL is less than 7mm.LLF exists in 21% cases,mainly below the first premolar(28.6%).The average angle of lateral lingual canal(LLC)and lingual bone plate is 147.95±18.14° for the dentate patients,and is 144.96±15.88° for the edentulous patients.LLC always is linked with MC,not attaching to the root pointed end generally.The detection rate of lingual foramen in anterior mandibular region is 100%.Only one lingual foramen was observed in 66% of the patients.Two lingual foramen were observed in 29% of the patients.Three lingual foramen were observed in 5% of the patients.The anterior lingual foramen was at the midline of the mandible in 78% of the patients;10% of the patients at the left of the midline,and 12% of the patients at the right of the midline.There were statistical significances as below :the average distance from the starting point of anterior lingual canal to the alveolar ridge crest for the patients with and without edentulous jaw are respectively 9.89±2.86 mm and 12.10±3.64 mm.The distances from the starting point of anterior lingual canal to the alveolar ridge crest for the patients with and without edentulous jaw have statistical significance(P<0.05).It was found on 94% of the images from MIC:the male average length was about 11.88±2.35 mm in the anterior loop of the mental nerve and female length is 10.78±2.07 mm.This difference has statistical significance(P<0.05).At the same time,the average distance of male and female group differences about the lower margin of mandible and labial bone plate and each measurement site MIC has statistical significance(P<0.05).At the beginning point,it closes to the buccal side.It closes to the lingual side when moving to the front of mandible.Conclusions CBCT can detect the above anatomical structure of the implant clearly through three-dimensional reconstruction.The clinician should take care to avoid the anatomical structure during the implant surgery.Preoperative CBCT examination has important clinical guiding significance for formulating the relevant surgery program.Figure10;Table12;Reference 166...