The asymptomatic patient, a 60-year-old man, was referred to a radiology clinic to undergo examination for the purpose of implant planning. The panoramic radiograph revealed no important alterations in the mandible (). The patient underwent multidetector computed tomography (MDCT) (Synergy Helicoidal, General Electric Company, Milwaukee, WI), with slices and intervals of 0.625 mm, field of view 15.8 cm, matrix 512 × 512, standard filter, 120 kV and 200 mA.\nThe tomographic images clearly showed multiple cavitary defects, two in the anterior region (anterior variant) and one in the posterior region (posterior variant) (Figures , , and ). Intracavitary tomographic density (Hounsfield units) suggested glandular tissue in the anterior defects and fat in the posterior defect.
A 76-year-old at death male Caucasian cadaveric head (fresh-frozen) was dissected. During routine dissection of the head, the mandible was dissected, and the soft tissues of the mandible were removed. After the mandible was separated from the head, a large bony defect was found on the lingual surface of the right mandible, which was located 25.2 mm anterior to the angle of the mandible and 3.3 mm superior to the inferior border of the mandible. The shape and size of the bony defect was oval and 10.8×6.0 mm, respectively (, ). The bony defect had a smooth surface and did not show any pathological condition. Therefore, it was determined to be an SBC. The SBC had continuity with the right mylohyoid groove. The depth of the SBC and width of the mandible at the SBC was 4.15 mm, 3.14 mm, respectively. The SBC was not observed on the left side.