Periodontal (gum) diseases, including gingivitis and periodontitis, are serious infections that, left untreated, can lead to tooth loss. The word periodontal means "around the tooth." Periodontal disease is a chronic bacterial infection that affects the gums and bone supporting the teeth.

Periodontal disease can have an effect on one tooth or many teeth. It begins when the bacteria in plaque (the sticky, colorless film that constantly forms on your teeth) causes the gums to become inflamed.

In the mildest form of the disease, gingivitis, the gums redden, swell and bleed easily. There is on most occasions little or no discomfort. Inadequate oral hygiene often causes gingivitis. Gingivitis is reversible with professional treatment and good oral home care.

Untreated gingivitis can advance to periodontitis. With time, plaque can spread and grow below the gum line. Toxins produced by the bacteria in plaque severely irritate the gums. The toxins stimulate the body to switch on a chronic inflammatory response.  This inflammation destroys the tissues and bone that support the teeth. Gums separate from the teeth, forming pockets (spaces between the teeth and gums) that become infected. As the disease progresses, the pockets deepen and more gum tissue and bone are destroyed. Often, this destructive process has very mild symptoms. Eventually, teeth can become loose and may have to be extracted.

Types of Periodontal Disease

There are many forms of periodontal disease. The most common ones include the following.

Gingivitis
Gingivitis is the mildest form of periodontal disease. It causes the gums to become red, swollen, and bleed easily. There is usually little or no discomfort at this stage. Gingivitis is reversible with professional treatment and good at home oral care.

Aggressive Periodontitis
A form of periodontitis that occurs in patients who are otherwise clinically healthy. Common features include rapid attachment loss and bone destruction and familial aggregation.

Chronic Periodontitis
A form of periodontal disease resulting in inflammation within the supporting tissues of the teeth, progressive attachment and bone loss and is characterized by pocket formation and/or recession of the gingiva. It is recognized as the most frequently occurring form of periodontitis. It is prevalent in adults, but can occur at any age. Progression of attachment loss usually occurs slowly, but periods of rapid progression can occur.

Periodontitis as a Manifestation of Systemic Diseases
Periodontititis, often with onset at a young age, associated with one of several systemic diseases, such as diabetes.

Necrotizing Periodontal Diseases
An infection characterized by necrosis of gingival tissues, periodontal ligament and alveolar bone. These lesions are most commonly observed in individuals with systemic conditions including, but not limited to, HIV infection, malnutrition and immunosuppression.

Source: American Academy of Periodontology