Toothache, also known as dental pain, is pain in the teeth and/or their supporting structures, caused by dental diseases or pain referred to the teeth by non-dental diseases.
Common causes include inflammation of the pulp, usually in response to tooth decay, dental trauma, or other factors, dentin hypersensitivity (short, sharp pain, usually associated with exposed root surfaces), apical periodontitis (inflammation of the periodontal ligament and alveolar bone around the root apex), dental abscesses (localized collections of pus, such as apical abscess, pericoronal abscess, and periodontal abscess), alveolar osteitis ("dry socket", a possible complication of tooth extraction, with loss of the blood clot and exposure of bone), acute necrotizing ulcerative gingivitis (a gum infection, also called "trenchmouth"), temporomandibular disorder and others.
Pulpitis is classified as reversible when the pain is mild to moderate and lasts for a short time after a stimulus (for instance, cold or sweet); or irreversible when the pain is severe, spontaneous, and lasts a long time after a stimulus. Left untreated, pulpitis may become irreversible, then progress to pulp necrosis (death of the pulp) and apical periodontitis. Abscesses usually cause throbbing pain. The apical abscess usually occurs after pulp necrosis, the pericoronal abscess is usually associated with acute pericoronitis of a lower wisdom tooth, and periodontal abscesses usually represent a complication of chronic periodontitis (gum disease). Much less commonly, non-dental conditions can cause toothache, such as maxillary sinusitis, which can cause pain in the upper back teeth, or angina pectoris, which can cause pain in the lower teeth.