Imaging in Periodontology: 2D versus 3D Visualization Techniques

Introduction To Periodontal Diseases

Periodontal disease is the leading cause of tooth loss in the elderly population and shows an increasing incidence with age. It consists of several disorders of the periodontium, including gingivitis and periodontitis, which represent chronic infectious diseases. The presence of certain bacteria initiate plaque and calculus formation supra- and subgingival, affecting the soft tissues surrounding the teeth and causing inflammation. This gingivitis associated with bleeding of the gums, can progress to periodontitis when soft tissue attachment loss and/or supporting bone loss is seen. This results in pocket formation between the teeth and the remaining soft tissues or bone (see Figure 1) and may affect one to all teeth and eventually, when left untreated, lead to tooth loss.

Figure 1.

The two main topographic manifestations of alveolar bone loss. (A) Incisor and premolar radiographs revealing an overall horizontal breakdown of bone. The distance from the CEJ (white line) to the actual bony crest (red line) is larger than 1.5mm (the green line should be the healthy bone level) and appears similar for all teeth. (B) The radiograph of the maxillary molars reveals a non-uniform pattern of bone loss. Note that actual bone levels are difficult to assess because of radiographic superposition of the bony structures.

In addition, there is strong evidence that periodontal diseases are associated to certain systemic diseases such as cardiovascular disorders (Khader, 2004). Many studies have shown the importance of early detection of periodontal disease, in relation to the prevention of tooth loss and/or the patient’s general health (Oliveira Costa, 2007; Slots, 2003; Seymour, 2007). Diagnostic tools are therefore crucial for accurate assessment of the periodontal status. One problematic issue is the fact that the pattern of attachment loss is extremely variable. The loss of bony support can reveal either a horizontal breakdown (horizontal bone loss) or an angular breakdown (vertical bone loss) (see Figure 1). A normal alveolar crest lies within 1 to 1.5mm distance of the cemento-enamel junction (CEJ).