What is tooth decay?

Caries (from Latin: caries = putrefaction) is defined as a bacterial infectious disease of the teeth . The acid produced by bacteria in the plaque damages the tooth enamel. This damage becomes visible as discoloration or painful "holes" in the tooth.

Caries is particularly common on molars and in the spaces between the teeth. It is one of the most common disease worldwide, in Germany almost every adult is affected. If left untreated, tooth decay can lead to tooth loss. However, tooth decay can often be prevented with proper oral hygiene .

Tooth decay: origin and causes

Bacteria in the oral cavity together with food residues and saliva form a biofilm that attaches to the teeth as dental plaque (also: plaque). Certain bacteria in this coating, especially the so-called mutans streptococci and lactobacilli, feed by converting carbohydrates , especially sugar, from food into acid. This removes minerals from the tooth enamel.

As a rule, the saliva then has the task of remineralizing the damaged tooth enamel. But if the acid load becomes too great, it no longer works. Then tooth decay occurs: the tooth enamel becomes porous, damage and holes form, cariogenic microorganisms can penetrate deeper and deeper into the tooth substance.

What causes tooth decay?

The three main causes of tooth decay are:
plaque, sugar and time .

An unhealthy diet with lots of sweets and high-sugar drinks such as juices and soft drinks favors the multiplication of bacteria and thus the development of plaque and acid. If plaque and bacteria are not removed regularly by thorough toothbrushing, the acid has too much time to act on the tooth enamel - and the repair effect of the saliva can no longer compensate for the stress.

If tooth decay develops despite regular brushing and a low-sugar diet, other risk factors can also play a role. Smoking, for example, promotes the build-up of dental plaque and weakens the repair function of saliva. Smokers are therefore more likely to develop tooth decay than non-smokers.

Even with stress the risk of tooth decay increases: The production of saliva is reduced, and the enamel is often additionally burdened by grinding teeth at night . Certain medications can also reduce saliva production.

Baby teeth are more prone to tooth decay because their enamel is less hard than permanent teeth. The constant availability of sweet drinks from the bottle can further increase the risk of tooth decay in children.

 

In the visible area of ​​the tooth ( tooth crown ), the dentin is sealed off from the outside by tooth enamel . Inside the tooth, the dentin protects the pulp , which contains blood and lymph vessels, nerves and connective tissue. In the dentine there are dentine channels through which stimuli (pressure and temperature) are transmitted to the tooth nerves.

Since the tooth consists mainly of dentine, treatments must be carried out in the dentine, especially in the case of caries. The aim here is to remove all affected areas, but at the same time to preserve the dentine substance which is still healthy as far as possible. The hole is then closed with a suitable, dentin-adhesive filler. There are biocompatible artificial dentines for this purpose.

Where does tooth decay most often occur?

Tooth decay in adults occurs primarily where plaque is difficult to remove. It is comparatively rare on the incisors and is usually recognized in good time in order to take effective countermeasures.

It occurs more frequently in the spaces between the teeth, on the rear molars and wisdom teeth or in the area of ​​bridges and braces . Teeth with many deep furrows on the chewing surface (so-called fissures), which are difficult to keep clean, are particularly prone to tooth decay.

Caries can also form under crowns if the carious areas were not completely removed during dental treatment before the crown was placed or caries bacteria get under the crown due to insufficient cleaning at the edge of the crown.

The so-called root caries (also: tooth neck caries) occurs on exposed tooth necks. A receding gum, often caused by an inflammation of the gum tissue ( periodontitis ), precedes dental caries.

The risk of cervical caries increases with age, as the gums recede over time. Diabetics also have an increased risk of developing the disease, as they suffer from periodontitis more than average.

The stages of tooth decay

Incipient caries, i.e. an initially invisible, superficial demineralization of the tooth enamel, can be reversed by using fluorides in the toothpaste. Experts differentiate between four stages in the further course of caries:

• If the demineralization of the tooth enamel continues, white spots appear on the teeth. The dentin, the main component of the tooth substance, is not yet affected.
• In the next step, the caries breaks through the tooth enamel and spreads in the dentin. This offers less resistance than the harder enamel, the caries can progress faster.
• If the tooth decay develops further, it gradually attacks the pulp and progresses to the root.
• Finally, the tooth pulp decays in a purulent manner, and the inflammation spreads to the surrounding jawbone.

The symptoms of tooth decay

Recognizing tooth decay is not easy, especially at the beginning of the disease. In the initial stage, it does not cause pain and whitish or light brown discoloration of the tooth enamel is often difficult to see.

The first symptom is usually an increased sensitivity of the teeth. Patients feel a drag on cold or sweet food and drinks or when talking and breathing in cold air. The first damage to the tooth substance can sometimes be felt as sharp-edged areas on the tooth with the tongue.

In principle, you should go to the dentist as soon as you notice changes in the tooth surface, tooth color (i.e. brownish, black, but also white spots) or bad breath. Although these can also have other causes, they often indicate early-stage tooth decay or at least an imbalance in the bacterial composition in the saliva or too much dental plaque.

The teeth usually only hurt when the tooth decay has advanced further towards the root. If the inflammation is already advanced, a throbbing toothache can be felt even without external stimuli, which can also radiate into the neck and ears. Swelling on the cheek or the lymph nodes usually only occurs when the surrounding tissue has already been attacked.

Tooth decay or not? Diagnosis at the doctor

The dentist first examines the suspect tooth for external signs of tooth decay with the help of mirrors. A test for increased sensitivity of the tooth, for example with the aid of an air blower, also gives indications of the onset of caries.

To confirm the caries diagnosis, the doctor can also take x-rays . This is particularly helpful if no hole is visible from the outside or a caries attack is suspected under a filling, sealant or crown.

Remove and cure tooth decay

How do patients get rid of tooth decay? If the tooth substance has not yet been damaged and no holes have been made in the tooth enamel, fluoride gels can help in the early stages to stop tooth decay and to remineralize the tooth enamel.

Patients can "brush away" discoloration and plaque on their teeth or have them removed by a professional teeth cleaning service, but carious damage to the tooth substance must be treated by a dentist.

With caries therapy, the doctor first removes the carious areas completely mechanically and then closes the holes in the tooth substance with fillings. Because unlike the cells in bones or skin, the body does not reproduce dead cells of the tooth substance. So caries damage in the tooth does not heal by itself.

If the caries has already penetrated to the tooth nerve, a root canal treatment is necessary. The dentist must remove the inflamed pulp in the root canal and close the root canal with a filling.

Fillings, inlays and crowns

When replacing the removed tooth substance, patients can choose between plastic fillings (e.g. made of amalgam or composite) and inlay fillings, so-called inlays (e.g. made of gold or ceramic). Each filling method and each material has specific advantages and disadvantages and differs in effort and cost. Let the dentist advise you on your individual case.

The statutory health insurance companies bear the cost of caries treatment for tooth-colored composite fillings on visible front teeth and for amalgam fillings in the area of ​​the posterior and molar teeth. If amalgam is not an option for a patient for medical reasons, the health insurance companies will also take on composite fillings for other teeth.

When inserting the filling, there must be no steps or gaps at the transition between tooth and filling substance. Otherwise cariogenic bacteria can settle here, get under the filling and cause tooth decay there again. All fillings have in common that there must still be enough healthy tooth material to securely attach the filling.

If this is not the case, a crowning of the damaged teeth or a complete removal of the tooth with or without subsequent dentures is possible.

Treating tooth decay without drilling

When removing the damaged tooth substance, the following applies: As much as necessary, as little as possible. Usually the dentist works with the drill. If only small areas of the tooth are affected, caries removal with a laser or ultrasound is also an option . The health insurance company does not cover the costs for this.

Another alternative to the drill is the so-called caries infiltration. However, this can only be used in the initial stage, before holes have appeared in the tooth substance. The dentist removes the surface of the affected area with a gel and then applies a liquid plastic that penetrates the porous tooth enamel and is hardened there. This prevents harmful acids from penetrating. Patients also have to pay for this procedure privately.