Periodontitis (peri = around, odont = tooth, -itis = inflammation) refers to a number of inflammatory diseases affecting the periodontium — that is, the tissues that surround and support the teeth. Periodontitis involves progressive loss of the alveolar bone around the teeth, and if left untreated, can lead to the loosening and subsequent loss of teeth. Periodontitis is caused by bacteria that adhere to and grow on the tooth's surfaces, along with an overly aggressive immune response against these bacteria. A diagnosis of periodontitis is established by inspecting the soft gum tissues around the teeth with a probe and radiographs by visual analysis, to determine the amount of bone loss around the teeth. Specialists in the treatment of periodontitis are periodontists; their field is known as "periodontology" and "periodontics".

Chronic Periodontitis, the most common form of the disease, progresses relatively slowly and typically becomes clinically evident in adulthood. Aggressive Periodontitis is a rarer form, but as its name implies, progresses more rapidly and becomes clinically evident in adolescence. Although the different forms of periodontitis are all caused by bacterial infections, a variety of factors affect the severity of the disease. Important "risk factors" include smoking, poorly-controlled diabetes, and inherited (genetic) susceptibility.

Epidemiology

Periodontitis is very common, and is widely regarded as the second most common disease worldwide, after dental decay, and in the United States has a prevalence of 30-50% of the population, but only about 10% have severe forms.

Studies found an association between ethnic origin and periodontal diseases. In the USA, African-Americans have a higher prevalence of periodontal disease compared with Latin individuals as well as non-Hispanic people of European descent. In Israeli population, individuals of Yemenite, North-African, Asian, or Mediterranean origin have higher prevalence of periodontal disease than individuals from European descent. This could be attributed to genetic predisposition as well as social-cultural-behavioral differences (eg., smoking, oral hygiene, access to dental treatment) between populations.

Etiology

Periodontitis is an inflammation of the periodontium—the tissues that support the teeth. The periodontium consists of four tissues:

• the gingiva, or gum tissue;
• the cementum, or outer layer of the roots of teeth;
• the alveolar bone, or the bony sockets into which the teeth are anchored;
• the periodontal ligaments (PDLs), which are the connective tissue fibers that run between the cementum and the alveolar bone.

The primary etiology, or cause, of gingivitis is poor oral hygiene which leads to the accumulation of a bacterial matrix at the gum line, called dental plaque. Other contributors are poor nutrition and underlying medical issues such as diabetes. New FDA-approved finger nick tests are being used in dental offices to identify and screen patients for possible contributory causes of gum disease such as diabetes. In some people, gingivitis progresses to periodontitis - with the destruction of the gingival fibers, the gum tissues separate from the tooth and deepened sulcus, called a periodontal pocket. Subgingival bacteria (those that exist under the gum line) colonize the periodontal pockets and cause further inflammation in the gum tissues and progressive bone loss. Examples of secondary etiology would be those things that, by definition, cause plaque accumulation, such as restoration overhangs and root proximity.