What factors contribute to the development of caries?
Four causal factors must coincide for caries to develop. These four factors include the tooth as host, the food as substrate, the microorganisms themselves and time. As early as 1889, W. D. Miller established the theory of caries development, which is still fundamental today, stating that only when these four factors come together can caries develop at all.
If only one factor is missing, it is practically impossible. In addition to the four fundamental factors, there are also influencing factors, such as the nature of saliva or the individual genetic and anatomical composition of the tooth structure, which can make the development of caries more difficult or easier. In connection with this, caries can only develop if microorganisms can settle on a tooth for a certain period of time and if metabolizable substrate is available. If the substrate is promptly removed by brushing or flossing, the bacteria have no food to metabolize it and cause caries to develop. One of the bacteria primarily responsible for the development of caries is the bacterium Streptococcus mutans.
How does the development of caries take place?
Caries occurs when microorganisms can settle on a tooth with existing substrate (= food residues) for a long time. Through the metabolism of microorganisms, such as bacteria, the food is broken down into acids. These acids decalcify the hard tooth substance and thus damage the tooth.
This damage is called caries. The bacteria within the oral cavity are always present and can settle on the tooth in the form of plaque if oral hygiene is poor and food is cheap for them. Plaque is a dental plaque that cannot be dissolved by mere rinsing with water and can only be removed by mechanical tooth cleaning.Low molecular weight carbohydrates are a substrate or food that is beneficial to the bacteria, including above all the household sugar sucrose, which is also called cane or beet sugar.
The bacteria are able to split the sucrose by their metabolism into glucose (=single sugar) and fructose (= fruit sugar). The metabolic process produces acid as a waste product for the bacteria, which damages the tooth as caries. The pH-value in the oral cavity becomes acidic, which supports the bacteria in the development of caries and the demineralization of the enamel.
Scientific studies have shown that primarily sucrose is particularly cariogenic and its decomposition products (glucose and fructose) do not serve the bacteria as an active substrate. Fructose, the fruit sugar in fruit, is rather unattractive for bacteria. However, the reasons why this is the case are still unclear.
Furthermore, caries has the tendency to grow and expand. Once it has developed by decalcifying the enamel, caries destroys it until it reaches the subsequent layer of hard tooth substance, the dentin. Since the dentin is softer in composition and therefore more permeable than the enamel, the carious lesion eats its way more quickly here.
Once the pulp is finally infected by the caries, the nerves and blood vessels inside are destroyed and the tooth dies. To a certain extent, the caries is reversible, which means that it is reversible or can be stopped. If only the superficial enamel layer of the tooth is weakened by an initial caries, which is not yet palpable with a dental probe, the tendency to spread can be stopped by fluoride application and the active form of the caries can be transformed into an inactive form. In the process, the caries can be permanently prevented from spreading in the development phase by regular fluoridation. This might be of interest to you: Fluoridation of the teeth
