title: Radiographic considerations for the regional anatomy in the posterior mandible.
abstract: BACKGROUND
  Previous studies of the inferior alveolar nerve have used cadaveric specimens in small patient groups. The purpose of this study was to describe the anatomy in the posterior mandible with respect to the inferior alveolar nerve (IAN) using computed tomography (CT) images in a large patient population. We hypothesize that CT scans are an important component of a thorough treatment plan for minimizing risk to the IAN and optimizing surgical outcomes.
  
  
  METHODS
  CT scans of 195 patients (62 males and 133 females; age range: 22 to 88 years) were evaluated retrospectively. With the aid of computer software, cross-sectional images were examined at 5-mm increments distal to the mental foramen to the ascending ramus. Four measurements were made at each cross-sectional image. The distances from the IAN to the: 1) alveolar crest (CN); 2) buccal cortical plate (BN); 3) lingual cortical plate (LN); and 4) inferior border (IN) were measured.
  
  
  RESULTS
  Most measurements for males and females were significantly different. Mean values were as follows (males/females): CN, 13.85 ± 0.43/11.98 ± 0.40 mm (P <0.01); BN, 4.98 ± 0.15/4.47 ± 0.11 mm (P <0.01); LN, 2.93 ± 0.12/3.19 ± 0.10 mm (P <0.10); and IN, 7.76 ± 0.16/7.00 ± 0.15 mm (P <0.01). The 95% confidence intervals indicated that many patients had limited bone volume in the buccal shelf or ascending ramus.
  
  
  CONCLUSIONS
  Given the high degree of variability in mandibular bone volume surrounding the IAN and the position of the IAN, the use of CT scans should be considered for surgical procedures in the posterior mandible when there is risk of injury to the IAN.
authors.affiliation: Department of Periodontics, University of Illinois at Chicago, Chicago, IL 60612, USA.
authors.forename: Natasha
authors.initials: N
authors.lastname: Yashar
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Engeland
authors.forename: Alan L
authors.initials: AL
authors.lastname: Rosenfeld
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Walsh
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Califano
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001641:Bicuspid; D015519:Bone Density; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008340:Mandibular Nerve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D008875:Middle Aged; D008963:Molar; D012189:Retrospective Studies; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D061221:Trigeminal Nerve Injuries / Q000517:prevention & control; D055815:Young Adult