Radiographic Appearance of the Periodontium
Dental x-rays are an important addition to the clinical assessment of the periodontium. To recognize the disease, dental hygienist must be able to recognize normal radiographic appearance of the periodontium. Periodontal anatomy visible on x-rays includes the alveolar bone, periodontal ligament
space, and cement.
Gum is noncalcified soft tissues that are not visible on the picture.
1. Radiolucent and Contrast structures and materials
A. Radiolucent materials and structures easily penetrated by x-rays.
1. Most x-rays can pass through these objects and structures, in order to expose the x-ray. Radiolucent areas appear as dark gray to black in the picture.
2. Examples radiolucent structures of the tooth pulp, periodontal ligament space, periapical abscess, bone marrow spaces in the bones, defects and bone loss.
B. Radiopaque materials and structures to absorb or to resist the passage of x-rays.
1. Radio-opaque areas appear light gray to white on x-ray.
These structures absorb a large portion of x-rays, so very few x-rays reach the radiograph.
2. Examples of contrast structures and materials silver metallic (amalgam restorations) and newer composite restorations, enamel, dentin, cellulose stones, and compact or cortical bone.
2. Identification of periodontal tissues on Radiographs. Components of periodontal tissues that can be identified on x-rays include the alveolar bone, periodontal ligament space, and cement (Fig. 20-1).
A. Cortical Bone
1. Cortical bone is the outer surface of the bone, and consists of layers bones are tightly Packed together.
a. In the upper jaw, the cortical bone is a thin shell.
B. On the lower jaw, cortical bone dense layer.
2. Radiographic appearance of Cortical bone
a. The lower border of the mandible appears on the x-ray as a thick white border.
B. Interdental alveolar ridges between the teeth in both jaws appear on the x-ray as a thin white line out axial bone.
c. Grid-like pattern of spongy bone, which fills the interior of the alveolar ridge appears on the x-ray as a sample of delicate white trim in the bone.
B. The Alveolar Ridge. The normal level of the alveolar bone is approximately 2 mm apical (see below) cementoenamel junction (FAC).
1. If the coronal bone level is within the limits from 3 mm FAC, bone level is normal.
2. It is unlikely that the loss of bone mass less than 3 mm can be found on the radiograph.