Bifid canals: identification of three clinical cases using cone-beam computed tomography images

http://dx.doi.org/10.1590/1981-8637201800030000113693 CLÍNICO CLINICAL| |CLINICAL CLÍNICO Bifid canals: identification of three clinical cases using cone-beam computed tomography images Canais bífidos: identificação de três casos por meio de imagens de tomografia computadorizada de feixe cônico Paulo de Camargo MORAES1 ORCID iD 0000-0001-5069-4600 Daniela Prata TACCHELLI1 ORCID iD 0000-0003-0907-1174 Rubens Gonçalves TEIXEIRA1 ORCID iD 0000-0003-0814-0940 Luciana Butini OLIVEIRA1 ORCID iD 0000-0002-8755-6540 José Luiz Cintra JUNQUEIRA1 ORCID iD 0000-0001-6788-4021 ABSTRACT Anatomical variations of mandibular canal have rarely been reported in the literature. The aim of this paper is to present three clinical cases of bifid mandibular canal diagnosed with cone-beam computed tomography (CBCT) as well as discuss its clinical implications. The first case is very interesting due to its anatomic variation verified in a panoramic radiograph during orthodontic planning, mimicking an odontogenic tumor. The second and the third cases were identified during tomographic evaluation for third molar exodontia. The diagnosis of bifid canals is extremely relevant in order to avoid complications during surgical procedures and implant placement as well as anesthesia failures which cause pain, paresthesia and bleeding. Furthermore, the shape of these anatomical variations can be confused with bone lesions. Indexing terms: Mandibular Nerve. Surgery, Oral. Diagnosis. RESUMO O objetivo deste trabalho é apresentar três casos clínicos de canais mandibulares bífidos, diagnosticados em imagens de tomografia computadorizada de feixe cônico (TCFC) e discutir as possíveis implicações clínicas destas variações. O primeiro caso relatado é bastante interessante devido à variação anatômica diagnosticada em uma radiografia panorâmica, indicada para o planejamento ortodôntico. A ocorrência do canal bífido mimetiza o aspecto de um tumor odontogênico. A presença de canal bífido no segundo e no terceiro caso clínico foi identificada durante a avaliação tomográfica para a exodontia de terceiros molares. O diagnóstico de canais bífidos é de grande relevância para evitar possíveis complicações durante a realização de cirurgias, instalação de implantes dentários e falhas de anestesias durante os procedimentos cirúrgicos que podem provocar dor, parestesia e sangramento. Além disso, estas variações anatômicas podem ser confundidas com lesões ósseas. Termos de indexação: Diagnóstico. Cirurgia bucal. Nervo mandibular. INTRODUCTION During the seven week of the uterine life the inferior alveolar nerve divides into mental and incisive branches that can show anatomic variant along its trajectory [1]. Originally, the mandibular canal transmits to the inferior alveolar artery a third division branch of the trigeminal nerve. The term bifid is derived from a Latin word meaning a cleft into two parts or branches [2]. 1 The first case of bifid mandibular canal was published by Patterson and Funk in 1973 [3]. The authors described a case of unilateral mandibular canal with two mental foramina which was shown in a panoramic and lateral jaw radiographs. A previous report had shown a case of trifid mandibular canal diagnosed during a preimplant radiographic evaluation [4]. Taking into consideration the anatomic variations and their implications during surgical procedures, Faculdade São Leopoldo Mandic, Instituto de Pesquisa São Leopoldo Mandic. Rua José Rocha Junqueira, 13, Bairro Swift, Campinas - SP, Brasil, CEP: 13045-755. Correspondência para / Correspondence to: PC Moraes E-mail:< >. ▼ ▼ ▼ ▼ ▼ Como citar este artigo / How to cite this article Moraes PC, Tacchelli DP, Teixeira RG, Oliveira LB, Junqueira JLC. Bifid canals: identification of three clinical cases using cone-beam computed tomography images. RGO, Rev Gaúch Odontol. 2018;66(3):263-266. http://dx.doi.org/10.1590/1981-8637201800030000113693 RGO, Rev Gaúch Odontol. 2018 Jul-Set; 66(3):263-266 PC MORAES et al. knowledge of bifid canals is paramount for dental surgeons [5-7]. The occurrence of bifid mandibular canal is extremely variated in the dental literature. A review made by Sanchis et al.8 of 2,012 panoramic radiographs during 1996 to 1999 resulted in 1,276 women and 736 men (mean age 40.4 years). Only 7 cases (0.35%) were found in radiographic images suggesting double mandibular canal, three of them were confirmed by computed tomography images. A previous study [9] had reported that 0.08% of radiographs presented a double canal. Langlais et al. [10] found 0.95% of bifid mandibular canals. Nortje et al. [11] found 0.9% in 3,612 panoramic radiographs. Zografos et al. [12] found 0.4% to the incidence during 700 panoramic evaluations. Moreover, there are different classifications of the mandibular canal variations proposed by Carter & Keen [13], Nortje et al. [11] and Langlais et al. [10]. The present paper reports three cases of bifid canals using cone-beam computed tomography (CBCT). CASE REPORTS Figure 1. Panoramic reconstruction of CBCT image (A) and a cropped panoramic CBCT (B) demonstrating the bifid mandibular canal mimicking an odontogenic tumor. Case 1 A 21-year-old female was referred to the dental office for a routine dental appointment and orthodontic treatment and the dentist asked her for a panoramic radiography. After the radiographic analysis, the dentist verified an oval, painless, well delimited radiopacity area in the left mandibular ramus which showed a sclerotic halo near the mandibular canal. A computed tomography was performed and to our surprise, there was a bifid mandibular canal, mimicking an odontogenic tumor. The tomography showed an arm-shaped, dense image, diverting from the mandibular canal reaching the left alveolar crist (Figure1). The patient was elucidated and oriented to continue an orthodontic treatment. Case 2 A 33-year-old male was referred for a CBCT scan due to third molars exodontia and during the radiographic examination a radiographic image was observed which suggested a manbibular bifid canal near to the right mandibular foramen. A cone beam tomography image was asked in order to confirm the alteration and planning the third molar surgery (Figure 2). 264 RGO, Rev Gaúch Odontol. 2018 Jul-Set; 66(3):263-266 Figure 2. A and B. White arrows showing the bifid mandibular canal on CBCT images. Bifid canals: three case reports Case 3 A 32-year-old female was referred for third molar exodontia due to recurrences of pericoronaritis. During the surgical planning, the panoramic radiograph showed an alteration of mandibular canal in the near the apex of third molar suggesting a bifid mandibular canal that was confirmed during a cone-beam computed tomography evaluation (Figure 3). No anesthesia failure was observed and surgery procedures were painless, with no bleeding during the transoperative period. Some authors [4] reported a case of trifid mandibular canal discovered during treatment planning for dental imp (...truncated)