A toothache or tooth pain is caused when the nerve in the root of a tooth or surrounding a tooth is irritated. Dental (tooth) infection, decay, injury, or loss of a tooth are the most common causes of dental pain. ... Often, gum disease will not result in any pain. A toothache is a pain in or around a tooth that may be caused by: Tooth decay. Abscessed tooth. Tooth fracture. A damaged filling. Repetitive motions, such as chewing gum or grinding teeth. Infected gums.