Oral and Maxillofacial Radiology (OMD 361): Periodontal Disease Interpretation

Periodontium and Periodontal Disease

• The term periodontium refers to the tissues that invest and support the teeth, including the gingiva and alveolar bone.
• The normal anatomic landmarks of alveolar bone include the lamina dura, alveolar crest, and periodontal ligament space.

Normal Radiographic Appearance of Alveolar Bone

• The lamina dura appears as a dense radiopaque line around the roots of the teeth.
• The alveolar crest is located approximately 1.5 to 2.0 mm apical to the cementoenamel junctions of adjacent teeth.
• The shape and density of the alveolar crest vary between the anterior and posterior regions of the mouth.
• In the anterior regions, the alveolar crest appears pointed and sharp, and is normally very radiopaque.
• In the posterior regions, the alveolar crest appears flat, smooth, and parallel to a line between adjacent cementoenamel junctions.

Periodontal Disease

• Periodontal disease refers to a group of diseases that affect the tissues around the teeth.
• The disease may range from a superficial inflammation of the gingiva to the destruction of the supporting bone and periodontal ligament.
• The gingiva appears swollen, red, bleeding, and soft tissue pocket formation is seen.

Radiographic Appearance of Alveolar Bone Affected by Periodontal Disease

• The alveolar crest appears indistinct, and bone loss is seen.
• Periodontal disease may result in severe destruction of bone and loss of teeth.

Clinical and Radiographic Examination

• The clinical examination must include an evaluation of the soft tissues (gingiva) for signs of inflammation (e.g., redness, bleeding, swelling, pus).
• Radiographs allow the dental professional to evaluate periodontal disease, provide an overview of the amount of bone present, and indicate the pattern, distribution, and severity of bone loss.

Radiographic Interpretation of Periodontal Disease

• The dental radiographer must be familiar with the radiographic appearance of periodontal disease.
• All radiographs should be evaluated for bone loss and examined for other predisposing factors that may contribute to periodontal disease.
• Bone loss can be described in terms of the pattern, distribution, and severity of loss.

Predisposing Factors

• Calculus is a stone-like concretion that forms on the crowns and roots of teeth due to the calcification of bacterial plaque.
• Calculus appears as pointed or irregular radiopaque (white or light) extending from the proximal root surfaces on a dental radiograph.
• Defective restorations act as potential food traps and lead to the accumulation of food debris and bacterial deposits.

Limitations of Radiographic Diagnosis

• Superimposition and a two-dimensional image bring about the following problems:
  • Difficulty in differentiating between the buccal and lingual crestal bone levels.
  • Only part of a complex bony defect is shown.
  • Dense tooth or restoration shadows may obscure buccal or lingual bone defects, and buccal or lingual calculus deposits.
  • Bone resorption in the furcation area may be obscured by an overlying root or bone shadow.
• Information is provided only on the hard tissues of the periodontium, since the soft tissue gingival defects are not normally detectable.
• Bone loss is detectable only when sufficient calcified tissue has been resorbed to alter the attenuation of the X-ray beam.
• Technique variations in film and x-ray beam positions can affect the appearance of the periodontal tissues.
• Exposure factors can have a marked effect on the apparent crestal bone height.