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Stages of tooth decay

Tooth decay is a disease that attacks the dental hard tissues and spreads into the interior of the tooth to form a cavity. It causes localized, progressive destruction of the enamel, i.e. the outer surface, and then the dentin beneath the enamel. Deep decay can reach the dental pulp, where the nerve and blood vessels are located.

The main causes of tooth decay are a diet high in sugars and poor dental hygiene. After each meal, food debris clings to the teeth. If it is not brushed away, the bacteria in the mouth transform the sugars in the food debris into acids.


Healthy tooth


Early stage of tooth decay. Only the top level of the enamel is affected. During this stage, the patient feels no pain. This is the best time to treat a cavity. If the enamel has not been perforated, the dentist can treat the problem with fluoridated agents, with no need for restoration. He or she may also recommend other measures to stop the decay and encourage remineralization of the tooth. This is the medical approach to dealing with caries, as opposed to the surgical approach, meaning restoration.


When decay reaches the dentin (light brown), the tooth becomes sensitive to hot and cold. The patient may feel intermittent pain. At this stage it is still early enough to treat the problem just with a restoration (surgical approach).


When the decay attacks the dental pulp (pink), the pain becomes severe and persistent. The patient has no choice but to have major restorative work and a root canal treatment, or the tooth will have to be extracted.


If the infection (dark brown) spreads to the entire dental pulp, the patient may experience an abscess, a bacterial infection that causes acute, piercing pain. Antibiotics may have to be prescribed before the dentist can treat the problem. As in the previous stage, the patient will need major restorative work and a root canal treatment, or have the tooth extracted.