ABSTRACT
A firm grasp of normal radiographic anatomy is helpful to avoid overinterpretation. Normal alveolar bone appears gray and relatively uniform throughout the dental arch. The crowns of the teeth are covered with a thin layer of enamel. Enamel is the most radiodense structure in the body, because it is 97% mineralized. The root canals should appear regular and smooth. Root canals should all appear similar in width in relation to the size of the tooth. The periodontal ligament should be of uniform width around the tooth. There are several normal anatomic findings that are commonly misinterpreted in dental images as being pathologic, including findings affecting the maxilla and the mandible. On radiographs of the mandibular cheek teeth, a wide, horizontal radiolucent line courses parallel to and just dorsal to the ventral cortex of the mandible. The ventral cortex is the relatively thin radiodense structure just below the mandibular canal.
