19: The periodontal tissues and periodontal disease

The periodontal tissues and periodontal disease

Introduction

An overall assessment of the periodontal tissues is based on both the clinical examination and radiographic findings – the two investigations complement one another. Unfortunately, like many other indicators of periodontal disease, radiographs only provide retrospective evidence of the disease process. However, they can be used to assess the morphology of the affected teeth and the pattern and degree of alveolar bone loss that has taken place. Bone loss can be defined as the difference between the present septal bone height and the assumed normal bone height for any particular patient, taking age into account. In fact radiographs actually show the amount of alveolar bone remaining in relation to the length of the root. But this information is still important in the overall assessment of the severity of the disease, the prognosis of the teeth and for treatment planning.

Radiographs are therefore used to:

Selection criteria

Several radiographic projections can be used to show the periodontal tissues. Those recommended by the Faculty of General Dental Practice (UK) in their 2013 booklet Selection Criteria for Dental Radiography (3rd Edn) are summarized in Table 19.1.

Table 19.1

Summary of the main recommendations for imaging the periodontal tissues based on the Faculty of General Dental Practice (UK)’s 2013 Selection Criteria for Dental Radiography (3rd Edn)

Recommendation Evidence-based grading*
Horizontal bitewings if a patient has generalised pocketing <6 mm (BPE scores of Code 3) and little or no recession. C
Vertical bitewings if a patient has pocketing 6 mm or more (BPE scores of Code 4), supplemented by paralleling technique periapicals at sites where the alveolar bone is not shown on the bitewings. C
Bitewings (horizontal or vertical depending on pocket depth), supplemented by paralleling technique periapicals if necessary if a patient has localised pocketing C
A paralleling technique periapical if a periodontal/endodontic lesion is suspected C
CBCT is not indicated as a routine method of imaging periodontal bone support C
Small volume, high resolution CBCT may be indicated in selected cases of infra-bony defects and furcation lesions, where clinical and conventional radiographic examination do not provide the information needed for patient management C

*Evidence-based grading C = based on evidence from expert committee reports or opinions and/or clinical experience of respected authorities and indicates an absence of directly applicable studies of good quality.

In addition, digital radiography and image manipulation, including subtraction and densitometric image analysis (see Ch. 3), may assist in showing and measuring subtle changes in fine alveolar and crestal bone pattern. However, these techniques require the inclusion of a reference object of known density and a highly reproducible positioning technique to be helpful.

Radiographic features of healthy periodontium

A healthy periodontium can be regarded as periodontal tissue exhibiting no evidence of disease. Unfortunately, health cannot be ascertained from radiographs alone, clinical information is also required.

However, to be able to interpret radiographs successfully observers need to know the usual radiographic features of healthy tissues where there has been no bone loss. The only reliable radiographic feature is the relationship between the crestal bone margin and the cemento-enamel junction (CEJ). If this distance is within normal limits (2–3 mm) and there are no clinical signs of loss of attachment, then it can be said that there has been no periodontitis.

The usual radiographic features of healthy alveolar bone are shown in Figs 19.1 and 19.2 and include:

Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 19: The periodontal tissues and periodontal disease
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