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cone beam – international magazine of cone beam dentistry

| case report use of CBCT 04 cone beam 2 2016 The indispensable use of CBCT in the posterior mandible Author: Dr Souheil R. Hussaini, UAE The submandibular fossa (SF) is an important anatomic landmark of the mandible, where the sub- mandibular gland resides. During dental practise, particular attention is paid to SF when conducting the placement of dental implants and other surgical procedures. Any procedure undertaken has to be carried out with great care and attention in order to avoidperforationofthisarea.Anatomicalvariations of SF can occur, such as a deeply prominent and flat area with no depression. On very rare occasions, the mylohyoid ridge cannot be detected radiographi- cally or bimanually as the observation of this varia- tion is not always possible using a conventional ra- diograph. However, as a modern imaging resource, cone beam computed tomography (CBCT) allows an accuratethree-dimensionalassessmentofSFaswell as the identification of its degree of concavity. The aim of this article is to discuss the successful circumventionofSFasaresultofCBCTimagestaken duringthetreatmentofa65-year-oldnon-smoking, healthy male. Primary implant stability required an implant length longer than the previously failed implant. A stable insertion of the implant between SF and the inferior alveolar nerve (IAN) was made possible by utilising CBCT. The patient presented no sensorial disturbance in the region and the treat- ment was considered successful 14 months after restoration. Furthermore, this clinical case demonstrates the importanceof3-Dimaginganditsclinicalnecessity, as it enables the practitioner to reach a definitive diagnosis during treatment planning in spite of the patient’s misleading complaint. The submandibular fovea (or submandibular fossa orsubmaxillaryfovea)isanimpressiononthemedial side of the body of the mandible below the mylo- hyoid line. It is the location for the submandibular gland.1 Mandibles with lingual concavity pose a po- tentiallyincreasedriskoflingualcorticalperforation during surgery, particularly with an endosseous im- plant placement. Cross-sectional imaging provides excellent delineation of mandibular anatomy and givesimportantinformationonthedepthofthesub- mandibular gland fossa during preoperative assess- ment of the posterior mandible for dental implant fixture placement and other surgical procedures.2, 3 Radiographically, SF can be seen as an undefined ovoidradiolucentareainboththerightandleftsides of the mandible. Conventional radiographs widely used in dental practice, such as periapical and pan- oramic, provide a two-dimensional (2-D) image of a three-dimensional(3-D)structure.4,5 Forthisreason, SF may not be clearly visible in most cases, due to the superimposition of anatomic landmarks;5-8 the pattern of trabecular bone,9 the thinning of the mandible as well as the location below the mylo- hyoid line.5-7 Nowadays, CBCT represents an advanced technol- ogyindentalpractice.Thistechnologyallowsanac- curate three-dimensional (3-D) evaluation of osse- ousstructuresinthemaxillofacialregionandmakes it possible to assess SF in sagittal, axial, and coronal slicesandtoobtaindetailedinformationconcerning thisanatomiclandmark.5,7,8,10 TheimportanceofSFin dental practice, especially for dental implant place- ments and other surgical procedures in mandibular molarregions,ishighlightedbytheliteratureonthis subject.2, 3 The detection of SF location and depth is important in order to avoid perforation, haemor- rhage or asphyxia due to difficulty in breathing following suffocation.11 In addition, an effective di- agnostic radiographic technique of SF enables the practitioner to place an implant between SF and the inferior alveolar nerve (IAN).2, 3, 5–7, 9, 10 22016