Gingivitis begins with plaque. This invisible, sticky film, composed primarily of bacteria, forms on your teeth when starches and sugars in food interact with bacteria normally found in your mouth. Brushing your teeth removes plaque, but it re-forms quickly, usually within 24 hours.
Plaque that stays on your teeth longer than two or three days can harden under your gumline into tartar (calculus), a white substance that makes plaque more difficult to remove and that acts as a reservoir for bacteria. What's more, you usually can't get rid of tartar by brushing and flossing — you'll need a professional cleaning to remove it.
The longer plaque and tartar remain on your teeth, the more they irritate the gingiva, the part of your gum around the base of your teeth. In time, your gums become swollen and bleed easily.
Although plaque is by far the most common cause of gingivitis, other factors can contribute to or aggravate the condition, including:
- Drugs. Hundreds of prescription and over-the-counter antidepressants and cold remedies contain ingredients that decrease your body's production of saliva. Because saliva has a cleansing effect on your teeth and helps inhibit bacterial growth, this means that plaque and tartar can build up more easily.
Other drugs, especially anti-seizure medications, calcium channel blockers and drugs that suppress your immune system, sometimes can lead to an overgrowth of gum tissue (gingival hyperplasia), making plaque much tougher to remove.
- Viral and fungal infections. Although bacteria are responsible for most cases of gingivitis, viral and fungal infections also can affect your gums. Acute herpetic gingivostomatitis is an infection caused by the herpes virus that frequently leads to gum inflammation and to small, painful sores throughout your mouth. Oral thrush, which results when a fungus normally found in your mouth grows out of control, causes creamy white lesions on your tongue and inner cheeks. Sometimes these lesions spread to the roof of your mouth, your tonsils and your gums.
- Other diseases and conditions. Some health problems not directly associated with your mouth can still affect your gums. People with leukemia may develop gingivitis when leukemic cells invade their gum tissue. Oral lichen planus, a chronic inflammatory disease, and the rare, autoimmune skin diseases pemphigus and pemphigoid can cause gums to become so severely inflamed that they may peel away from the underlying tissue.
- Hormonal changes. During pregnancy, your gums are more susceptible to the damaging effects of plaque. The problem is compounded if you have morning sickness — nausea and vomiting may make it hard to brush your teeth regularly.
- Poor nutrition. A poor diet, especially one deficient in calcium, vitamin C and B vitamins, can contribute to periodontal disease. Calcium is important because it helps maintain the strength of your bones, including the bones that support your teeth. Vitamin C helps maintain the integrity of connective tissue. It's also a powerful antioxidant that counters the tissue-destroying effects of free radicals — substances produced when oxygen is metabolized by your body.