Anatomic variations and lesions of the mandibular canal detected by cone beam computed tomography.

PURPOSE: 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.

Anatomic variations and lesions of the maxillary sinus detected in cone beam computed tomography for dental implants.

OBJECTIVE: To evaluate the presence of anatomic variations and lesions of the maxillary sinus in cone beam computed tomography (CBCT) of the maxilla required for dental implant planning. MATERIAL AND METHODS: This transversal prevalence study evaluated a sample of 500 consecutive CBCT exams. The inclusion criteria were CBCT exams of the maxilla required for dental implant planning. The CBCT exams were independently evaluated by two oral and maxillofacial radiologists who assessed the presence of anatomic variations and lesions of the maxillary sinus. As most of the CBCT exams did not allow the evaluation of the area close to the maxillary sinus roof, anatomic variations that take place at this site were not assessed. RESULTS: The anatomic variations detected were pneumatization (83.2%), antral septa (44.4%), hypoplasia (4.8%), and exostosis (2.6%). The identified lesions were mucosal thickening (≤3 mm in 54.8% and >3 mm in 62.6%), polypoid lesions (21.4%), discontinuity of the sinus floor (17.4%), air-fluid level (4.4%), bone thickening of the maxillary sinus wall (3.8%), antroliths (3.2%), discontinuity of the sinus lateral wall (2.6%), sinus opacification (1.8%), and foreign body (1.6%). CONCLUSION: Anatomic variations and lesions of the maxillary sinus were common findings in CBCT exams of the maxilla required for dental implant planning. As some of these conditions can modify dental implant planning and must require specialized treatment, its recognition is noteworthy in dental practice, and especially in implantology. The amount and significance of the anatomic variations and lesions detected in this study reinforces the importance of computed tomography in preoperative dental implant planning.

Avaliação de caninos superiores impactados por meio de tomografia computadorizada de feixe cônico / Evaluation of impacted maxillary canines using Cone Beam Computed Tomography

Sessenta e quatro pacientes (45 mulheres e 19 homens) com um total de setenta e sete caninos superiores impactados (unilateral e bilateral) foram analisados por meio de tomografia computadorizada de feixe cônico usando imagens obtidas com o tomógrafo i-CAT. Foram avaliadas as variações de localização e inclinação desses caninos, bem como a reabsorção de dentes adjacentes e das corticais ósseas. Quanto à localização, 52 caninos apresentavam a coroa localizada por palatino em relação aos dentes adjacentes, 15 por vestibular e 10 com localização transalveolar. Quanto à inclinação, 63 caninos estavam inclinados para mesial, 2 para distal, 6 em posição vertical e nenhum em posição invertida. Reabsorção radicular foi observada em 10 dentes, sendo 7 reabsorções do incisivo lateral e 3 do incisivo central. Cinquenta e seis casos apresentavam reabsorção das corticais ósseas, sendo 37 da cortical palatina, 15 da cortical vestibular e 4 de ambas as corticais. Conclui-se, no estudo realizado, que a impacção de caninos superiores é mais comum em mulheres, na posição mesial e palatina, e que as reabsorções acometem mais os incisivos laterais.