Toothache

A toothache is pain located in the teeth or their supporting structures. It is the most common type of pain experienced in the mouth or face. While most toothaches are odontogenic, meaning they come from dental issues, some are non-odontogenic. This means the pain is referred to the teeth from other parts of the body. For example, maxillary sinusitis can cause pain in the upper back teeth. Even angina pectoris, a heart condition, can cause pain in the lower teeth.

To understand toothache, one must understand how the body senses it. The pulp and the periodontal ligament both contain nociceptors, which are pain receptors. However, the pulp lacks proprioceptors for motion and mechanoreceptors for pressure. Because of this, pain from the dentin-pulp complex is often poorly localized. In contrast, pain from the periodontal ligament is usually well localized. The periodontal ligament is incredibly sensitive; it can detect pressure from objects smaller than 10–30 μm.

One major cause of pain is pulpitis, which is inflammation of the dental pulp. This inflammation can be triggered by mechanical, thermal, chemical, or bacterial irritants. Common causes include tooth decay, dental trauma like a fracture, or an imperfect filling seal.

Because the pulp is encased in a rigid outer shell, it cannot expand when it swells. This increased pressure can compress blood vessels, leading to ischemia, or a lack of oxygen. This process can result in pulp necrosis, which is the death of the pulp tissue.

Pulpitis is categorized into two distinct types based on its severity. Reversible pulpitis involves mild to moderate pain that lasts a short time after a stimulus like cold. This can be resolved if the cause is removed or if the tooth produces tertiary dentin to insulate the pulp. Irreversible pulpitis involves severe, spontaneous pain that lingers long after a stimulus. If left untreated, irreversible pulpitis progresses to pulp necrosis and eventually apical periodontitis.

Another common issue is dentin hypersensitivity, which affects about 15% of the population. This causes sharp, short-lasting pain triggered by cold, sweet, or spicy substances. It is most often caused by gingival recession, where receding gums expose the tooth roots. While the pulp remains healthy during hypersensitivity, the exposed dentin reacts intensely to triggers. Over time, the pulp may adapt by producing more tertiary dentin to increase the protective layer.

Infections can also lead to abscesses, which are localized collections of pus. An apical abscess occurs near the root tip, often following pulp necrosis. A periodontal abscess forms in the gum crevices, usually due to chronic periodontitis where pockets are deeper than 3mm.

These abscesses typically cause a deep, throbbing pain. There is also a variant called a gingival abscess, which is limited to the gum margin and often results from trauma like a toothpick.

Other complications include food impaction and acute necrotizing ulcerative gingivitis (ANUG). Food impaction occurs when debris, such as fibrous meat, becomes trapped in an "open contact" between teeth. This causes the gingival papilla to swell, feel tender, and bleed.

ANUG is a sudden, severe gum infection characterized by bleeding, painful ulcers, and bad breath.

These conditions highlight how even small disruptions in oral health can lead to significant discomfort.

Toothache is a major public health issue with massive numbers. In 2013, there were 223 million cases of toothache caused by dental caries in permanent teeth. There were also 53 million cases involving baby teeth. Because of the high demand for relief, dental surgery is thought to have emerged as the first specialty of medicine. Proper oral hygiene is the best way to prevent the diseases that lead to these painful conditions.