Gum disease, also called gingivitis, is inflammation of the gums. It’s usually the result of plaque building up on your teeth due to less than effective brushing and flossing habits. Gingivitis can make your gums swell and bleed when you brush or floss. Untreated gingivitis can lead to periodontitis, a more serious infection. As periodontitis progresses, the infection can spread to your jaw and bones. It can also cause an inflammatory response throughout the body.