Chronic Infectious Disease: Periodontitis

Periodontitis is a chronic infectious disease of the supporting tissues of the teeth. Due to bacterial infection, periodontal tissues become inflamed, and are slowly destroyed by the action of the inflammatory process. If the disease is left untreated, teeth lose their ligamentous support to the alveolar bone, alveolar bone itself is resorbed, and the teeth become mobile and are finally lost.1 Traditionally, periodontitis was thought to be strictly environmental in origin. Despite this belief, it was recognized that only a portion of the variability of disease in the population could be explained by environmental factors alone. In a classic study of the natural history of periodontitis, Loe etal found that among individuals with poor oral hygiene and no access to dental care, some developed disease at a rapid rate, whereas others experienced little or no …show more content…
Common features of complex human diseases (for example Alzheimer’s disease, Crohn’s disease and cardiovascular diseases) are that they present mostly a relatively mild phenotype, are slowly progressive and chronic in nature.3 The patho-physiology of complex diseases is characterized by various biological pathways, leading to similar clinical phenomena. Importantly, complex diseases are associated with variations in multiple genes, each of which has a small overall contribution and relative risk for the disease process.4 Similarly to other complex diseases, we estimate that, for periodontitis, at least 10 and possibly as many as 20 disease-modifying genes may be involved. However, it is important to realize that the number and types of disease-modifying genes for the same condition may not be equal for different forms of periodontitis and different ethnic populations; their effect is also influenced by environmental factors (gene–environment