The most common cause of gingivitis is poor oral hygiene that encourages plaque to form. Plaque is an invisible, sticky film composed mainly of bacteria. Plaque forms on your teeth when starches and sugars in food interact with bacteria normally found in your mouth. Brushing your teeth at least twice a day and flossing each day removes plaque. Plaque requires daily removal because 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). Tartar can also develop resulting from the mineral content in your saliva. Tartar makes plaque more difficult to remove and creates a protective shield for bacteria. You usually can't get rid of tartar by brushing and flossing — you need a professional dental cleaning to remove it.

The longer that 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. Tooth decay (dental caries) also may result.

Jan. 22, 2014