Radiographic Techniques and Structures

Attenuation

• Radiolucent structures appear darker on radiographic images and are less dense, while radiopaque structures appear whiter and are more dense.
• Structures that are more mineralized will appear more radiopaque, while less mineralized structures appear more radiolucent.

Examples of Radiolucent & Radiopaque Objects

• Examples of radiolucent objects include air, depressions, foramina, canals, sutures, fossae, fissures, and meati.
• Examples of radiopaque objects include spines, tubercles, tuberosities, prominences, septa, teeth, foreign body materials.

Intraoral Images

• Periapical images are used to visualize the entire tooth and supporting structures, including the apex of the tooth.
• Bitewing images are used to diagnose interproximal caries.
• Occlusal images are used to visualize a larger area of the jaws, such as the entire maxillary or mandibular arch.

Extraoral Images

• Panoramic images provide a wide view of the entire dentition and surrounding structures.
• The focal trough in a panoramic image is where the X-ray beam focuses to produce the image, and only structures within the focal trough will be clear.
• The panoramic image should visualize all teeth, the temporomandibular joints (TMJs), the maxillary sinuses, the nasal cavity, and the mandible.

Teeth

• Teeth are comprised of a crown and a root, and are covered by enamel.
• The dentin is the inner layer of the tooth and surrounds the pulp chamber.
• The pulp chamber contains the pulp which holds blood vessels and nerves.
• The pulp chamber narrows as it extends down the root, forming the root canal.

Supporting Structures

• Trabecular bone, cancellous bone, and cortical bone are all part of the jawbone.
• The alveolar crest is the bony margin of the tooth sockets.
• The periodontal ligament space is the area between the root of the tooth and the alveolar bone.
• The lamina dura is a dense layer of bone that lines the periodontal ligament space.
• Crestal soft tissues are the soft tissues that surround the teeth, such as the gingiva.

Variations in Pattern of Cancellous Bone

• The pattern of trabeculae and marrow spaces in cancellous bone varies throughout the jaws.
• The anterior maxilla has a fine cancellous bone pattern, characterized by thin, numerous trabeculae and small, numerous marrow spaces.
• The posterior maxilla has a fine cancellous bone pattern, characterized by thin, numerous trabeculae and numerous, larger marrow spaces.
• The anterior mandible has a coarser cancellous bone pattern, characterized by thicker, fewer trabeculae than the maxilla, and larger marrow spaces.
• The posterior mandible has a coarsest cancellous bone pattern, characterized by usually larger trabeculae, horizontal in nature, and larger marrow spaces.

Other Structures

• Restorative materials, such as amalgam, composite, porcelain, and gutta-percha, are used to repair damaged teeth.
• Implants are used to replace missing teeth.
• Air will appear radiolucent on radiographic images.

Attenuation - Summary

• The degree to which different structures attenuate X-rays, or absorb radiation, determines how they appear on radiographs.
• The greater the density, the more radiopaque the structure will appear.
• Metal is the most radiopaque material, followed by enamel, dentin, cementum, bone, and soft tissues.
• Air is the most radiolucent material.

Explore the differences between radiolucent and radiopaque structures in radiographic images. This quiz covers the types of images used in dental radiography, including intraoral and extraoral techniques. Test your knowledge on common examples and their significance in diagnosis.