Tooth decay: all you need to know about cavities

Definition of tooth decay

Tooth decay is an infectious disease . The enamel of the tooth is the first affected. A cavity forms in the tooth and then the decay spreads to depth. If the decay is not treated, the hole enlarges and the decay can reach the dentin (layer under the enamel). Pain begins to be felt, especially with hot, cold or sweet. Cavities can spread to the pulp of the tooth. We then speak of toothache. Finally, a tooth abscess can appear when bacteria attack the ligament, bone or gum tissue.Tooth decay

The sugars are said to be one of the main culprits in the attack on the enamel . This is because the bacteria present in the mouth, mainly the bacteria Streptococcus mutans and lactobacilli, break down sugars into acids. They bind to acids, food particles and saliva to form what is called dental plaque, which causes tooth decay. Brushing your teeth removes this plaque.

Dental caries, which is very common, affects milk teeth (a decayed milk tooth must be treated even if it is likely to fall out) and permanent teeth. Rather, they affect the molars and premolars, which are more difficult to clean when brushing. Cavities never heal on their own and can lead to tooth loss.


The symptoms of dental caries are very variable and depend in particular on the stage of development of the caries and its location. At the very beginning, when the enamel is the only one affected, decay can be painless. The most common symptoms are:

  • dental pain, which gets worse over time;
  • sensitive teeth;
  • sharp pain when eating or drinking something cold, hot, sweet;
  • pain when biting;
  • brown spot on the tooth;
  • pus around the tooth;

People at risk

The heredity plays a role in causing cavities. Children, adolescents and the elderly are more likely to develop cavities.


The causes of dental caries are multiple but sugars , especially when consumed between meals, remain the main culprits. For example, there is a link between sugary drinks and cavities or between honey and cavities 2 . But other factors such as snacking or bad brushing are also involved.


Cavities can have serious consequences for teeth and general health. It can, for example, cause severe pain , abscesses sometimes accompanied by fever or swelling of the face, problems with chewing and nutrition, teeth that break or fall out, infections … Cavities must therefore be treated. as soon as possible.

Risk factors

The oral hygiene is a very important parameter in the development of dental caries. A diet high in sugar also greatly increases the risk of developing cavities.

A lack of fluoride would also be responsible for the appearance of cavities. Finally, eating disorders such as anorexia and bulimia or gastroesophageal reflux are pathologies that weaken the teeth and facilitate the onset of cavities.


The diagnosis is easily made by the dentist since cavities are often visible to the naked eye. He asks about the pain and tenderness of the teeth. An x-ray can confirm the presence of cavities.


Cavities are very common. More than nine out of ten people have had at least one cavity. In France, more than a third of six-year-olds and more than half of 12-year-olds 1 would have been affected by this infection. In Canada, 57% of children between the ages of 6 and 12 have had at least one cavity.

The prevalence of caries affecting the crown of the tooth (the visible part that is not covered by the gums) increases until the age of forty and then stabilizes. The prevalence of cavities that affect the root of the tooth, often through loosening or erosion of the gum, continues to increase with age and is common among seniors.

Our doctor’s opinion

As part of its quality approach, Passeportsanté.net invites you to discover the opinion of a health professional., gives you his opinion on tooth decay :

Prevention is better than cure. In the case of tooth decay, prevention is effective and involves good oral hygiene with regular brushing, at least twice a day, ideally three times a day after each meal. The important thing in the treatment of cavities is to consult quickly. Regular visits to the dentist are essential because they allow cavities to be treated before they reach an advanced stage. An installed decay that has attacked the pulp of the tooth requires more complicated and expensive care than a decay that has not crossed the enamel.

Prevention and treatment of cavities

How to prevent the appearance of tooth decay?

An essential point to prevent cavities is to brush your teeth as soon as possible after each meal, without forgetting to change your toothbrush regularly, with fluoride toothpaste. The use of interdental floss is strongly recommended. Chewing sugarless chewing gum increases the amount of saliva in the mouth and helps neutralize acids in the mouth better. Chewing gum can therefore reduce the risk of cavities. But sugar-free chewing gum should not be a substitute for brushing!

Beyond good oral hygiene, it is necessary to avoid snacking and watch your diet. Eating sugary foods between meals that get stuck in the teeth greatly increases the risk of developing cavities. Certain foods such as milk, ice cream, honey, table sugar, soft drinks, grapes, cakes, cookies, candies, cereals or chips tend to stick to the teeth. Finally, babies who fall asleep with a bottle of milk or fruit juice in their bed are at risk of developing cavities.

The dentist can also prevent the appearance of cavities in the teeth by applying a resin to the surface of the teeth. This technique, mainly intended for children, is called furrow sealing. It can also offer a varnish application. The healthcare professional can also advise a fluoride 3.4 if necessary (tap water is often fluoridated). Fluoride has been shown to have a cario-protective effect.

Finally, it is essential to consult a dentist every year in order to detect cavities even before it is painful.

In France, the Health Insurance has set up the M’tes dents program. This program offers an oral check-up at 6, 9, 12, 15 and 18 years old. These preventive examinations are free. More information on the website In Quebec, the Régie de l’Assurance Maladie (RAMQ) offers children under 10 the following program free of charge: one exam per year, emergency exams, x-rays, fillings, prefabricated crowns, extractions, root canals and oral surgery.

Caries treatment

Cavities that have not had time to reach the pulp of the tooth are easily treated and only require a simple filling. Once cleaned, the cavity is plugged with an amalgam or a composite. Thus, the pulp of the tooth is preserved and the tooth is alive.

For more advanced decay, the tooth canal will need to be treated and cleaned. If the decayed tooth is very damaged, devitalization and extraction of the tooth may be necessary. A dental prosthesis will be placed.

These treatments are generally performed under local anesthesia.

The pain caused by tooth decay can be relieved with paracetamol (acetaminophen such as Tylenol) or ibuprofen (Advil or Motrin). In case of abscess, antibiotic treatment will be necessary.

Complementary approaches to dental caries


Xylitol. Studies 5 have suggested the efficacy of xylitol in preventing caries. This natural sweetener would inhibit the bacteria Streptococcus mutans . Chewing gums containing xylitol could therefore be beneficial for the teeth.

Propolis. Some animal trials have shown promising results with propolis, but in humans the results obtained remain mixed 6 . According to the author of a synthesis on the anti-decay properties of propolis, the results diverge because the composition of the propolis used during the tests varies 7 .

Cheese. The consumption of cheese could, according to numerous studies, prevent the onset of cavities 8 , 9,10 . Those responsible for this cariogenic effect are the minerals in cheese, in particular calcium and phosphorus. They would prevent the demineralization of teeth and even contribute to their mineralization 11 . A study 12 for its part suggested the effect on caries of consuming yoghurt, without however showing the same results for other dairy products such as cheese, butter or milk.

Tea. Tea, whether green or black, would also help prevent tooth decay. It would decrease the action of an enzyme present in saliva which has the role of breaking down the starch in foods into simple sugars. Green tea is said to have a beneficial effect on cavities thanks to its polyphenols which would limit the growth of bacteria associated with cavities 13,14,15 .

Cranberry. Consuming cranberries would reduce the formation of dental plaque and tooth decay. Be careful, however, because the juices that contain it are often rich in sugars and therefore bad for oral hygiene 16 .

Hop. Polyphenols, substances present in hops, according to certain studies 17,18 slow down the formation of dental plaque and therefore help prevent cavities.

To find out more about dental caries , we offers a selection of associations and government sites dealing with the subject of dental caries. This will allow you to find additional information and contact communities or support groups where you can learn more about the disease.

Mayo Clinic (see Cavities / tooth decay)
Information and health records in English.

Consumer Lab
Files and resources on nutritional and health products.

American dental association
Information site of the American dental association

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