It is often assumed that once you get a crown, you’ll never have a toothache in that tooth again. But surprisingly, a crowned tooth is as susceptible to pain as any other tooth. The pain can develop immediately after the crown is inserted or even many years later.
Dental Cement and Bite Changes
A toothache that develops soon after a crown is inserted is likely related to the gluing process or an uneven bite. Dental cements that glue the crown in place are acidic or rely on acidic primers, which can irritate the nerve in a tooth. This can cause pain or temperature sensitivity that lasts a few days or up to a year. New crowns are also painful when they cause an uneven bite. If when biting down, the crowned tooth meets the opposing teeth before all the others, pain may persist until the crown is filed down.
Cavities Under Crowns
Even with a crown, a new cavity can develop at the border of the tooth and the crown, in the same way it forms around the edge of a filling. The cavity is caused by dental plaque buildup in the area, leading to tooth decay. If the decay spreads beneath the crown or deeply into the tooth, the nerve tissue becomes inflamed and painful. Should bacteria from the decay actually reach the nerve, the nerve becomes infected and often requires root canal therapy. During this therapy, a small hole is drilled into the crown and the nerve and surrounding infected tissue are then removed through the hole.
Root Death and Root Fracture
A tooth that requires a crown was rarely normal beforehand. Crowns are often needed because of deep or large cavities. Even when the tooth is crowned, the nerve may have been sufficiently damaged by the pre-existing tooth problem that it dies. This can lead to a localized infection -- abscess -- in the area, which will generally require root canal therapy. Occasionally, even after such treatment, the infection comes back and further treatment may include replacing the crown. Also, like any other tooth, a crowned tooth sometimes develops a fracture in the root and needs to be removed.
Gum Issues and Cement Failure
The gums around a crowned tooth can recede with time, causing the root to become exposed and leading to hot or cold sensitivity. Gum recession is often associated with excessively forceful tooth brushing. Areas of gum recession are particularly susceptible to developing plaque buildup, which can lead to a painful gum infection. Cement leakage at the edge of the crown may occur in some people. This may be associated with pain in the tooth, although it is unclear whether leakage can actually cause pain. Failure of the cement to bond properly -- resulting in the crown moving or even coming off -- may also cause pain in a crowned tooth.
If you develop a toothache in a crowned tooth, contact your dentist's office. Whether the crown is new or established, a dental professional can investigate the cause of the pain and intervene if necessary.