Gingivitis is an inflammation of the gums surrounding the teeth. Gingivitis is one of many periodontal diseases that affect the health of the periodontium (those tissues that surround the teeth and include the gums, soft tissues, and bone).

Periodontal diseases are often classified according to their severity. They range from mild gingivitis, to more severe periodontitis, and finally acute necrotizing ulcerative gingivitis, which can be life threatening.

Bacteria can cause inflammation of the gums. Although bacteria are normally found in our bodies and provide protective effects most of the time, bacteria can be harmful. The mouth is a great place for bacteria to live. The warm, moist environment and constant food supply are everything bacteria need to thrive. If not for a healthy immune system, bacteria in the mouth would rapidly reproduce out of control overwhelming the body's defense system.

An infection begins when the body's immune system is overwhelmed. Gingivitis is an infection that occurs when bacteria invade soft tissues, bone, and other places that bacteria should not be. At the moment of infection, bacteria no longer help us, they begin to harm us. Infections, like other diseases, range from mild to severe or life threatening.