A fever that occurs with a toothache may mean an infection has developed in a tooth or surrounding gums.

An abscessed tooth is caused by an infection that develops in the tissue around a tooth. When the center of the tooth (pulp) dies because of damage or tooth decay, mouth bacteria start to overgrow. Bacteria spread from the root of the tooth to the tissue underneath it, creating a pus-filled pocket called an abscess.

An abscessed tooth can cause severe pain from the pressure against the tooth, bone, and nerves. An abscessed tooth may also make your gums swollen and red. If the abscess is left untreated, the pus may spread to tissues of your mouth, jaw, and face, causing a fever, bad taste in your mouth, and swelling in your jaw, face, or neck.

As the infection increases, your jawbone may begin to dissolve to make more room for swelling of the infected area. As the bone dissolves, it may relieve pressure and reduce pain, but the infection remains. If too much bone dissolves, there will be no support for the tooth, and the tooth may have to be removed.

An abscessed tooth may develop because of gum disease. Gum disease causes the gums to pull away from the teeth, leaving pockets. If one of these pockets becomes blocked, mouth bacteria can overgrow and an abscess may form.

Prompt dental care can help determine the cause of your fever and keep the tooth from dying.