Gingivitis is an inflammatory process

Gingivitis is an inflammatory process limited to the mucosal epithelial tissue surrounding the cervical portion of the teeth and the alveolar processes. Gingivitis has been classified by clinical appearance (eg, ulcerative, hemorrhagic, necrotizing, purulent), etiology (eg, drug-induced, hormonal, nutritional, infectious, plaque-induced), and duration (acute, chronic). The most common type of gingivitis is a chronic form induced by plaque. Acute necrotizing ulcerative gingivitis (ANUG, ie, trench mouth) is an acute infectious gingivitis.

You may have heard the adage "To keep your teeth, take care of your gums." That's good advice.
Gingivitis is one of the most common forms of gum (periodontal) disease. Gingivitis affects the tissues that surround and support your teeth.

The cause is bacteria that irritate your gums, leading to swelling and bleeding. Bacteria on your teeth - along with minerals in your saliva - form tartar (calculus), providing an environment for additional bacteria to accumulate and irritate your gums. Left unchecked, gingivitis can lead to a more serious form of gum disease called periodontitis. This long-term infection can eventually result in loss of your teeth.

Thorough daily brushing, regular flossing and frequent professional cleaning reduce your chances of developing serious gingivitis.