Gingivitis. Inflamed gums of a patient suffering from gingivitis. Several ulcers are seen at the base of the front teeth of the lower jaw. Gingivitis is an inflammation of the gums caused by dental plaque on the surfaces of the teeth. Plaque is a sticky coating that consists of bacteria, saliva and small particles of food. Toxins produced by the bacteria may irritate the gums. If untreated, gingivitis can progress to full periodontal disease, erosion of the tissues that support and attach the teeth. Gingivitis can be relieved with good oral hygiene.