Caries is an infection that affects practically all the inhabitants of our planet today. According to epidemiologists, even in the Middle Ages, the prevalence of caries in Europe was three times less than today's. The reason for the victorious march of a dental disease lies primarily in the fact that we eat.

The fact that the teeth attacked a persistent and difficult to destroy infection, partly to blame humanity itself. Today, most dentists stick to the version that the cariogenic bacterium Streptococcus mutans migrated into the oral cavity from the stomach 10-15 thousand years ago, when the first tribes of our ancestors switched to agriculture and cattle-breeding, abandoning the hunt, and began to consume less protein (meat) and more carbohydrates (cereals, vegetables and dairy products). Surprisingly, the infectious nature of caries has been reliably established less than half a century ago.

Bacteria responsible for the development of the carious process were identified at the beginning of the 20th century. But, in addition to the initiator of the initial stage of caries, S. mutans, among the "provocateurs", scientists later also discovered several other types of streptococci and lactobacilli that continue the process, and, in addition, the species of actinomycetes responsible for caries of the tooth root. The fact that the cause of an unpleasant disease is streptococci, it is quite logical. Microbes of this kind for thousands of years are present in the digestive system of humans and animals, usually without causing any harm.

To maintain their own lives, streptococci use the carbohydrates of our food, decomposing them with a record speed compared to other bacteria and leaving then alcohols, aldehydes or acids. With the advent of large cities and public catering, the carious bacterium seized more and more mouths, and the triumph of streptococcus reached after the industrial revolution, when refined sugar, lemonades and other foods high in sucrose - ideal for fast fermentation of carbohydrates - became cheap and affordable. It was then that plaque turned for cariogenic microbes into an ideal environment for parasitism.

Mechanism of destruction To understand how caries appear, it is first of all necessary to know that the enamel of the teeth is approximately 95% composed of the mineral - calcium hydroxyapatite Ca10 (PO4) 6 (OH) 2. Its hexagonal crystals combine into prisms and provide durability of bones and teeth. The enamel of only one incisor contains about 5 million mineral prisms.

Like all hydroxyl ("alkaline") minerals, hydroxyapatite is destroyed by the action of acids. This is due to a violation of the notorious acid-base balance, known to everyone for advertising chewing gums. When an acid enters the mouth, for example with a sip of wine, our body tries to neutralize it, and calcium from the enamel migrates into the saliva. And without calcium, mineral prisms crumble like card-shaped houses. If the process is repeated, the acids attack the dentin under the enamel. Then in the tooth appears carious cavity - cavern.

Especially "terrible" simple organic acids, such as acetic, lactic and citric. Therefore, when we drink wine or eat an orange, the enamel of our teeth is doomed to partial destruction. But acids appear in the mouth and without oranges. Streptococcus plaque feed on the carbohydrates that we eat, and the by-product of their fermentation is just aggressive acids. The simpler the carbohydrate, the faster the acid is formed from it. And this means that the more often we eat simple carbohydrates (glucose, fructose, sucrose), the more caries progresses.

Enamel, which forms the crown of the tooth, is the most solid substance in the human body. Nevertheless, it can not withstand the chemical attack of the products of vital activity of Streptococcus S. mutans.

Approximately the mechanism of development of this disease was described by the American dentist Willoughby Miller at the end of the XIX century, calling it the chemical-parasitic theory. This means that, on the one hand, the appearance of caries is a chemical process, but without microbial parasites, it would not be so large-scale or would be neutralized at all. According to the head of the department of caries prevention MGSU Edith Kuzmina, in the appearance of caries are to blame for three reasons: dental plaque with bacteria, carbohydrate food and weak resistance of tooth enamel. This means that there can only be three ways to fight caries: eat as few simple sugars (easily fermentable carbohydrates), make the tooth enamel more resistant to destruction and, finally, rid the teeth of the plaque in which streptococci are hidden.

Bitter sweet truth Of course, people knew about it for a long time, but people proved the role of diet in the appearance of caries only when in numerous independent experiments it was established that streptococci are present in plaque and in people who are free from caries. The first step in proving the "guilt" of sugar was made by Danish professor Frederick von der Feer from the Royal Dental College in Aarhus. In 1970, von der Feer conducted an experiment in which a group of volunteers with a good state of tooth enamel completely ruled out oral hygiene-they did not brush or rinse their teeth after eating. Half of them also several times a day rinsed the mouth with a 50% solution of sucrose. The lack of hygiene increased the number of bacteria in the plaque, but when comparing the teeth of those who rinsed the mouth with a sweet solution, more obvious signs of caries were found with the control group - the demineralization of the enamel and the appearance of spots on it.

If earlier, for example, in the not so distant 18th century, sugar was an expensive product and appeared in the diet of not everyone, now, according to dental surveys, most people in Russia and many other countries eat sweet daily. As Edit Kuzmin notes, it is not so much the amount of sweets consumed at a time that is important, but the frequency of its consumption.

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