A dental cavity or tooth decay can cause a severe tooth ache. When a cavity is small and in the outer enamel, there is usually no pain or symptoms at all. That is why it is important to have a dental examination two times a year. If cavities are caught with they are small, they are simple to treat and do not lead to a severe tooth ache. Tooth decay is caused by bacteria, simple carbohydrates (sugar) and acids. When left untreated, tooth decay allows bacteria to enter the inner layers of the tooth and an infection develops leading to a severe tooth ache.
An abscessed tooth occurs when bacteria enter the nerve chamber. In a naturally healthy tooth, the nerve chamber is closed and sealed off from the mouth. It is protected by the enamel, dentin and cementum which are all hard mineralized structures difficult for bacteria to penetrate. When these structures are damaged, bacteria enter the nerve chamber and begin to colonize and an infection develops called a tooth abscess (abscessed tooth). The technical name for an abscessed tooth is pulpitis. Abscessed teeth cause a severe tooth ache when bacteria create pus and it cannot drain. It builds up pressure inside of the tooth and irritates the nerve. If an abscess can drain, it usually is not painful but you can get a bad taste in your mouth from draining pus.
A periodontal infection or gum infection can cause a severe tooth ache by infecting the ligaments and bone around the tooth roots. When bacteria cause a gum infection, the bone and gum tissues is destroyed and a periodontal pocket develops. It can causes pain in the tooth or jawbone.
A cracked tooth, broken tooth or even a microscopic fracture in a tooth also produces a pathway for bacteria to enter the nerve chamber and cause and abscess.
Clenching & grinding
Clenching and grinding of teeth can cause tooth fractures or broken teeth leading to tooth abscesses. Also, clenching and grinding can put extra force on the tooth and cause inflammation in the nerve leading to a severe tooth ache.
Wisdom teeth, or third molars can cause a severe tooth ache. Some people have enough room for them so they come in without any problems, usually between the ages of 17-21. If you do not have enough room for your wisdom teeth to come in, they may partially erupt or remain impacted. In either of these situations, they can become infected or put excessive pressure on the tooth in front of them as they try to erupt unsuccessfully.