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ePaper created 2016-03-24, 17:16:09 | version 1.38.0
| case report 30 implants 1 2016 The indispensable use of CBCT in the posterior mandible Author: Souheil Hussaini, Dubai The submandibular fossa (SF) is an important an- atomic landmark of the mandible, where the sub- mandibular gland resides. During dental practice, particular attention is paid to SF when conducting the placement of dental implants and other surgi- cal procedures. Any procedure undertaken has to be carried out with great care and attention in or- der to avoid perforation of this area. Anatomical variations of SF can occur, such as a deeply prom- inent and flat area with no depression. On very rare occasions, the mylohyoid ridge cannot be detected radiographically or bimanually as the observation of this variation is not always possible using a con- ventional radiograph. However, as a modern imag- ing resource, cone beam computed tomography (CBCT) allows an accurate three-dimensional as- sessment of SF as well as the identification of its degree of concavity. The aim of this article is to discuss the successful circumvention of SF as a result of CBCT images taken during the treatment of a 65-year-old non-smoking, healthy male. Primary implant sta- bility 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 pa- tient presented no sensorial disturbance in the re- gion and the treatment was considered successful 14 months after restoration. Furthermore, this clinical case demonstrates the importance of 3-D imaging and its clinical neces- sity, as it enables the practitioner to reach a defin- itive diagnosis during treatment planning in spite of the patient’s misleading complaint. The submandibular fovea (or submandibular fossa or submaxillary fovea) is an impression on the medial side of the body of the mandible below the mylohyoid line. It is the location for the sub- mandibular gland.1 Mandibles with lingual concav- ity pose a potentially increased risk of lingual cor- tical perforation during surgery, particularly with an endosseous implant placement. Cross-sectional imaging provides excellent delineation of mandib- ular anatomy and gives important information on the depth of the submandibular gland fossa during preoperative assessment of the posterior mandible for dental implant fixture placement and other sur- gical procedures.2,3 Radiographically, SF can be seen as an undefined ovoid radiolucent area in both the right and left sides of the mandible. Con- ventional radiographs widely used in dental prac- tice, such as periapical and panoramic, provide a two-dimensional (2-D) image of a three-dimen- sional (3-D) structure.4,5 For this reason, SF may not be clearly visible in most cases, due to the super- imposition of anatomic landmarks;5-8 the pattern of trabecular bone,9 the thinning of the mandible as well as the location below the mylohyoid line.5-7 Nowadays, CBCT represents an advanced tech- nology in dental practice. This technology allows an accurate three-dimensional (3-D) evaluation of osseous structures in the maxillofacial region and makes it possible to assess SF in sagittal, axial, and coronal slices and to obtain detailed information concerning this anatomic landmark.5,7,8,10 The im- portance of SF in dental practice, especially for dental implant placements and other surgical pro- cedures in mandibular molar regions, is highlighted by the literature on this subject.2,3 The detection of SF location and depth is important in order to avoid perforation, haemorrhage or asphyxia due to dif- ficulty in breathing following suffocation.11 In ad- dition, an effective diagnostic radiographic tech- nique of SF enables the practitioner to place an 12016