Pulpitis, an inflammation of the dental pulp. This can be either reversible or irreversible. Irreversible pulpitis can be identified by sensitivity and pain lasting longer than fifteen seconds, although an exception to this may exist if the tooth has been recently operated on. Teeth affected by irreversible pulpitis will need either root canal treatment or extraction of the tooth.
Some causes of toothache are the more obvious culprits such as a cracked tooth, filling or veneer, dental caries from eating acidic, sweet foods that corrode the fillings and the tooth's protective enamel layer. This corrosion is caused from the bacteria that are present on the teeth which break down the sugars in refined foods and then excrete them in the form of acids, which then eat away at the protective enamel of the tooth, causing a cavity, infection and eventually toothache.
Atypical odontalgia is a form of toothache present in apparently normal teeth, or which persists after the supposedly offending tooth has been removed. Some sources consider atypical odontalgia to be a sub-type of atypical facial pain, although others treat them as the same entity. The pain, generally dull, often moves from one tooth to another for a period of 4 months to several years. The cause of atypical odontalgia is not yet clear, and many different theories have been proposed, including theories that the pain is psychogenic in nature. Some form of nerve deafferentation is plausible, but it is likely that AFP and atypical odontalgia are in truth umbrella terms for a collection of multiple different causes of pain which have not been properly diagnosed or are not yet fully understood.
The severity of a toothache can range from a mild discomfort to excruciating pain, which can be experienced either chronically or sporadically. This pain can often be aggravated somewhat by chewing or by hot or cold temperature. An oral examination complete with X-rays can help discover the cause. Severe pain may be considered a dental emergency.