Classification of periodontal diseases
The term “periodontal diseases” is usually used to describe the range of inflammatory conditions that affect the supporting tissues of the teeth, which are initiated by the accumulation of dental plaque. Potentially confusingly, in some instances, the term is alternately used to describe any condition affecting the periodontal tissues, which is not necessarily due to plaque accumulation and might be caused by any disease process. Here, and throughout this book, we use the conventional understanding for the term periodontal diseases to signify plaque-induced diseases. Other diseases that can affect the periodontal tissues are discussed further in < ?xml:namespace prefix = "mbp" />
A classification system’s basic attributes are to provide a structure to study the aetiology, pathological processes, and treatment of a specific disease or diseases and should also be flexible enough to permit the introduction of new diagnoses into the system as needed. The use of such a classification system for periodontal diseases is a convenient filing system for a broad spectrum of diseases and has developed as understanding about aetiology of periodontal diseases has increased during the past 20 years.
Diagnosis implies that a disease can be understood based on some of its key features and using this information will inform our overall treatment approach. However, reaching a diagnosis is often an inexact science because even when using a classification system, there is considerable overlap between categories and a “best fit” diagnosis (or differential diagnosis) is often reached after combining the aetiological factors elucidated during the patients’ medical, dental, and social histories with the clinical oral examination findings. Reaching a working diagnosis is crucial (
A classification system may, in principle, be based mainly on the distinct clinical features of the conditions or, alternatively, may be based mainly on their different aetiologies. It can be argued that a classification system based on aetiology might be most useful in informing treatment planning decisions. However, periodontal diseases, like many other common chronic diseases, have a complex aetiology in which a range of different locally acting and systemically acting factors can combine to cause the disease, and thus it is difficult to use an aetiology-based system of classification. Furthermore, the same aetiological conditions may combine in different patients to cause clinically distinct disease entities.
Plaque-related periodontal diseases are by far the most common of all conditions that can affect the periodontal tissues. Data from the 2009 United Kingdom Adult Dental Health Survey show that two-thirds of those examined had visible dental plaque on their teeth and other oral structures (e.g., dentures). In addition, 45% of people examined had pocket depths of ≥4 mm, and 9% of people examined had probing depths of ≥6 mm. Studies suggest that the overall prevalence of moderate to severe periodontitis in most populations throughout the world is approximately 15–20%. However, as noted previously, they are not the only possible conditions with such a presentation.
The classification for periodontal diseases and conditions is shown in
• Periodontal diseases—inflammatory conditions that involve the deeper periodontal tissues and that have resulted in loss of alveolar bone, associated periodontal ligament, and apical migration of the junctional epithelium
• Developmental or acquired defects—gingival recession and other mucogingival problems (discussed in
Adapted from Armitage (1999).
This classification, like all classifications, has prompted debate and disagreement, and no doubt as our knowledge of the aetiology and pathogenesis of periodontal diseases changes, new classification systems will be proposed. In addition, there is one obvious inconsistency: within the category “gingival diseases,” there is a specific section on gingival lesions that are not due to plaque, whereas in the “periodontal diseases” section there is no equivalent attempt at classifying non-plaque-induced conditions that can affect the deeper periodontal tissues.
Plaque-related gingival disease is almost ubiquitous in all populations, and this inflammatory reaction is a response to the microbial challenge presented to the gingival tissues. It can be modified by the presence of plaque-retentive factors, particularly dental restorations, dental caries, or abnormal tooth anatomy. It is usually painless and is reversible if meticulous oral hygiene is maintained. The clinical features are red, swollen gingivae often associated with accumulation of plaque and calculus/>