Periodontal diseases

Periodontal pathology is a science or a study of periodontal diseases. Periodontal diseases can affect one or more of the periodontal tissues/structures (e.g. alveolar bone, periodontal ligament, cementum and gingiva). While there are many different periodontal diseases that can affect these tooth-supporting tissues/structures, by far the most common ones are plaque-induced inflammatory conditions, such as gingivitis and periodontitis. Often the term periodontal disease or gum disease is used as a synonym for periodontitis, specifically chronic periodontitis. Periodontal disease ranges from the mildest stage, known as gingivitis, to severe stage, known, as periodontitis.

While in some sites or individuals, gingivitis never progresses to periodontitis, data indicate that periodontitis is always preceded by gingivitis.

In 1976, Page & Schroeder introduced an innovative new analysis of periodontal disease based on histopathologic and ultrastructural features of the diseased gingival tissue. Although this new classification does not correlate with clinical signs and symptoms and is admittedly "somewhat arbitrary," it permits a focus of attention pathologic aspects of the disease that were, until recently, not well understood. This new classification divided plaque-induced periodontal lesions into four stages:

Unlike most regions of the body, the oral cavity is perpetually populated by pathogenic microorganisms; because there is a constant challenge to the mucosa in the form of these microorganisms and their harmful products, it is difficult to truly characterize the boundary between health and disease activity in the periodontal tissues. The oral cavity contains over 500 different microorganisms. It is very hard to distinguish exactly which periodontal pathogen is causing the breakdown of tissues and bone. As such, the initial lesion is said to merely reflect "enhanced levels of activity" of host response mechanisms "normally operative within the gingival tissues."

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