What is caries?
Caries or cavities occur when bacteria in plaque (the biofilm that forms on the teeth) produce acid that gradually damages the tooth and creates a cavity. When the tooth is intact, bacteria are found on the tooth surface. These bacteria include saccharolytic bacteria, which feed on carbohydrates and then produce acid as a byproduct. The acid can soften the tooth enamel. If this process continues for a longer period, a cavity can develop through the enamel and into the dentin (the less hard substance of the tooth).
The main difference between dentin and enamel is that dentin contains more protein. Therefore, proteolytic bacteria can become more prominent in dentin and feed on the protein found in the tooth structure. The cavity can then continue to grow within the dentin because these proteolytic bacteria can obtain nutrients relatively undisturbed.
Bacteria live in plaque, but what exactly is plaque?
Plaque is a biofilm consisting of components of saliva (mucin, amylase, minerals, antibodies, and water), the oral bacterial flora (many different bacteria, including both beneficial and less beneficial bacteria), and carbohydrates from food.
When, for example, cariogenic bacteria (bacteria that are particularly associated with caries) feed on the carbohydrates we consume, acid is produced that attacks the teeth. The affected surface becomes demineralized, meaning that minerals are lost from the tooth. However, as long as the plaque remains present, these minerals remain within the plaque.
When the teeth are given a break from food intake for at least 2–3 hours, the tooth surface can instead remineralize. This means that minerals are returned to the affected tooth surface. Therefore, it is important to avoid frequent snacking so that remineralization can take place. Otherwise, demineralization may continue for longer periods and the progression of caries may accelerate.
Demineralization and remineralization – when do they occur?
Tooth enamel consists primarily of hydroxyapatite. When the environment around the teeth becomes more acidic than pH 5.5, hydroxyapatite begins to demineralize. Remineralization can occur at pH 5.5 and above.
One of the functions of saliva, in addition to washing away bacteria and helping protect the mucous membranes, is to buffer acidic conditions. From food intake until remineralization begins, it generally takes around 2–3 hours.
What happens in plaque when it remains undisturbed for a longer period?
The bacterial flora in our mouths consists of many different types of bacteria. Some of these bacteria are cariogenic and may become more prominent compared with other bacteria. Therefore, these bacteria can become increasingly selected for the longer plaque remains undisturbed.
Over time, the number of cariogenic bacteria can increase and the risk of caries becomes higher. This is why it is very important to brush your teeth thoroughly and also use dental floss. The goal is to remove existing plaque so that a new and more balanced bacterial flora can establish itself in the new plaque that forms.
Why do people get caries?
Caries can occur due to several factors, including:
- Frequent consumption of mainly rapidly fermentable carbohydrates
- Frequent snacking between meals
- Inadequate removal of plaque
- Insufficient fluoride protection
Can caries be prevented?
Yes, caries can be prevented.
One important measure is controlling sugar intake and limiting how frequently sugary foods and drinks are consumed. Thorough cleaning and regular fluoride exposure through fluoride toothpaste are also very important.
If a dentist determines that a patient has an increased risk of caries, fluoride varnish twice a year may also help slow the progression of caries.
In some cases, switching to a toothpaste with a higher fluoride concentration may also be appropriate, such as Duraphat toothpaste, according to the dentist's recommendation.
How can you prevent caries?
Instead of consuming smaller amounts of sugar several times throughout the day, it is recommended to limit sugar intake and avoid frequent exposure. One example is to reserve sweets for one occasion per week, such as Saturday sweets.
Eat filling portions at breakfast, lunch, and dinner to help avoid snacking between meals.
Brush your teeth twice a day with fluoride toothpaste for at least two minutes each time. An electric toothbrush can be used, and daily use of dental floss is recommended.
Fluoride mouthwash can be used as a supplement, but it should not be used immediately after brushing your teeth. Instead, consider using it around the middle of the day so that fluoride exposure is distributed throughout the day.
What happens to the tooth when caries develops?
When acid attacks begin in the enamel, the enamel becomes softer and weaker, and bacteria can also enter it. Once the decay reaches the dentin, it can continue to progress until it approaches the pulp, which can lead to toothache.
Caries often causes no symptoms until the damage has become more advanced. At that point, a root canal treatment may be necessary instead of simply placing a conventional composite filling.
How long does it take to develop caries?
It can normally take several years for caries to progress from the outer layer of the enamel to the boundary between enamel and dentin. In some cases, progression can be faster because dental caries is a multifactorial disease.
From the boundary between enamel and dentin to the pulp, progression can also take several years. When the decay approaches the pulp, toothache may occur.
Does caries need to be treated?
Caries is usually treated, but there are exceptions. Initial caries, sometimes called a white-spot lesion, is decay that is still limited to the enamel and does not always require invasive treatment. Fluoride treatment, sugar control, and thorough cleaning may be sufficient.
The same may apply to arrested caries lesions, which can sometimes occur on exposed tooth roots.
What happens if caries is not treated?
If a cavity is not treated in time, toothache may eventually develop. A root canal treatment is often required to address the infection, after which the tooth may need to be restored with either a composite filling or a crown.
If the decay continues for a prolonged period despite toothache, the damage may become so extensive that the tooth can no longer be saved. In that case, the tooth may need to be extracted. The resulting gap can be left as it is or replaced with, for example, a dental bridge or implant.
How is caries treated?
Initial caries is generally treated with fluoride, together with improved oral hygiene and control of risk factors.
Dentin caries is treated invasively by removing the decayed tooth material. Once the decayed material has been removed and healthy dentin remains, the tooth can usually be restored with a composite filling.
