title: Anatomic variations and lesions of the mandibular canal detected by cone beam computed tomography.
abstract: OBJECTIVE
  The mandibular canal is a significant anatomical structure in implant dentistry, and cone beam computed tomography (CBCT) is an important diagnostic image modality in this field of dentistry. The aim of this study was to evaluate the frequencies of anatomic variations and lesions affecting the mandibular canal in CBCT images of the mandible produced for dental implant planning.
  
  
  METHODS
  This cross-sectional study evaluated a sample of 250 CBCT examinations (500 mandibular canals). The inclusion criterion was CBCT examinations of the mandible requested for dental implant planning. The presence of anatomic variations and lesions affecting the mandibular canal was evaluated in the CBCT examinations. Moreover, the buccolingual position of the mandibular canal was evaluated in the molar region and in the ramus region. The CBCT exams were evaluated by one observer. The data were analyzed using descriptive and analytical statistics. The one-way ANOVA test was employed to compare the age between the anatomic variations. A paired t test was used to compare the buccolingual position between the molar region and the ramus region. Differences were considered significant when p values were lower than 0.05.
  
  
  RESULTS
  The anatomic variations detected were large-diameter mandibular incisive canal (51.6 %), ramification (12 %), and accessory mental foramen (3.2 %). No difference was observed in the age of the patients between the anatomic variations (p > 0.05). The identified lesions included hypomineralization of the canal walls (20.8 %), idiopathic osteosclerosis (8.8 %), osteolytic lesions (3.2 %), iatrogenic perforation of the mandibular canal (2.8 %), and fibro-osseous lesions (1.6 %). The distance between the mandibular canal and the vestibular cortical bone was higher in the molar region than in the ramus region (p < 0.05).
  
  
  CONCLUSIONS
  Anatomic variations and lesions affecting the mandibular canal were common findings in the CBCT images of the mandible produced for dental implant planning. An awareness of these alterations is important for dentistry because some of them might require treatment, change oral surgery planning and difficult inferior alveolar nerve anesthetic block.
authors: Department of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Guilherme Mariano Fiuza
authors: GM
authors: Leite
authors: Juliana Pelinsari
authors: JP
authors: Lana
authors: Vinícius
authors: V
authors: de Carvalho Machado
authors: Flávio Ricardo
authors: FR
authors: Manzi
authors: Paulo Eduardo Alencar
authors: PE
authors: Souza
authors: Martinho Campolina Rebello
authors: MC
authors: Horta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D063405:Anatomic Variation; D054893:Cone-Beam Computed Tomography; D003430:Cross-Sectional Studies; D003758:Dental Implantation, Endosseous; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008336:Mandibular Diseases / Q000000981:diagnostic imaging*; D008875:Middle Aged; D010347:Patient Care Planning; D011857:Radiographic Image Interpretation, Computer-Assisted