CLINICAL MEDICINE

Detailed explanation-1: -Structures that are cavities, depressions, or openings in bone such as a sinus, fossa, canal or foramen will allow x-rays to penetrate through them and expose the receptor. These areas will appear radiolucent or black on radiographic images.

Detailed explanation-2: -In a periapical radiograph, the enamel, which is the hardest substance in the human body, appears as the most radiopaque (lightest) part of the crown of the tooth. The dentin is a less-mineralized hard structure of the tooth between the enamel and the pulp and is not as radiopaque as the enamel.

Detailed explanation-3: -In the normal patient presenting to the oral and maxillofacial practitioner, the normal radiopaque structures are anatomical: the teeth, the bones of the jaws (including the middle-third of the face and nasal bones), the stylohyoid complex (including the hyoid bone), the skull base, and cervical vertebrae.

Detailed explanation-4: -The most common example of something radiopaque is the human skeleton. Bones cannot be seen through under radiation, which is why x-rays are such an effective way of visualizing bones.