Periodontitis is a complex inflammatory disease of the oral mucosal barrier and the supporting tissues of the teeth, resulting in destruction of the periodontal connective tissues. If left untreated, the alveolar bone is continually degenerated during the inflammatory process, the teeth lose their ligamentous support to the alveolar bone, become mobile, and are eventually lost.
Chronic periodontitis is one of the most common forms of periodontitis; it is the major cause of tooth loss in adults over 40. For the more severe forms of CP, the WHO reports that human populations are affected worldwide at prevalence rates of up to 20%. Aggressive periodontitis is the most severe form. It is characterized by a particularly rapid progression at an adolescent age (<35 years). Various environmental and life-style factors play a significant role in the etiology of periodontitis, with smoking being the major predisposing factor, but poor oral hygiene, coronary heart disease, diabetes, and stress further contribute to an increased risk. However, these factors do not always lead to the disease and there are highly susceptible and tolerant individuals. The genetic basis of periodontitis is well established, but has largely remained unexplained.