The structure of human teeth: an interactive diagram with definitions. The most terrible diseases that disfigure people Now let's talk about the anatomical structure of the tooth

For some, a tattoo or piercing remains a memory of rebellious youth, while others do not stop at the first underwear, turning their body into a real (sometimes shocking others) gallery over time. In our review, 10 people for whom body modification has become a fanatical hobby.

1. Enigma

Paul Lawrence is clearly a fan of jigsaw puzzles. This is clear at first glance. The man who swallows swords during performances and is no stranger to sticking an electric drill up his nostril is literally covered in blue puzzle pieces. Lawrence's skin is the creation of over 200 tattoo artists. Enigma is so unusual that he was even invited to star in one of the X-Files series.

2 Zombie Boy

In recent years, the theme of zombies has become very popular. Rick Genest spent over $4,000 Canadian on tattoos to look like a zombie. Most interestingly, he can hide his tattoos with ease (how he does this can be seen in the video). Genest, who lives in Quebec, got his first tattoo at the age of 16. Shortly thereafter, the young man left home and met the artist Frank Lewis in Montreal, who turned Genest into a zombie in six years.

3. Bear - big ears

Daryl Belmares has very big ears. To be more precise, he just has huge earlobes. They are so big that Belmares can literally wrap them around his face. The professional piercer now holds the world record for the most stretched earlobes in the world (they show holes 14 cm in diameter).

4 Hawaiian Mutant

Kala Kaivi looks like a real mutant: 75 percent of his body is covered in tattoos, he has a forked tongue, 70 piercings, numerous silicone implants in his face, and distended earlobes and nostrils. All this is pretty ordinary for the people on this list, but Kaiwi decided on a very bold and controversial step: he screwed metal spikes into the top of his skull. According to Kaiwi himself, this strengthens his connection with the native Hawaiian culture.

5. Etienne Dumont

When people think of art historians, what immediately comes to mind is a man in a neat suit, tie and fashionable glasses, who, with a glass of champagne in his hand, meticulously examines the exhibition of a new artist. Surely, the last thing that comes to mind is a man like Etienne Dumont from Geneva, who is completely covered in tattoos, has silicone horn implants on his forehead, large rings in each ear and piercings through his lips and nose. Dumont, 60, often referred to as "art alive," held his own photography exhibition in 2009 at the Chrysal Gallery in Geneva.

6 Zebra Man

Actor Horace Ridler is often called a professional freak. As the Great Omi or the Zebra Man, Horace easily stood out from the crowd of actors, as he was covered from head to toe in black and white stripes. To emphasize his tattoos, Ridler painted his lips with black lipstick and black polish on his nails. Before his death in 1969, Ridler explained that "underneath his whole image was an ordinary person."

7. Illustrated Lady

Julie Gnuz was unusual from birth. She suffers from a rare condition called porphyria, which causes skin to blister when exposed to sunlight, resulting in scarring. Paradoxically, Julie was advised by a doctor to do body art and hide scars behind tattoos. The 55-year-old woman made it into the Guinness Book of Records because 95 percent of her body is covered in tattoos.

8 Lizard Man

Eric Sprague from Austin, Texas cut his tongue in two (he was one of the first people to do this) and spent a whopping 700 hours on tattoos. The lizard man also sharpened his teeth to look like fangs, painted his lips green and stretched the nasal septum and earlobes.

9. Lucky Diamond Rich

Gregory Paul McLaren, better known as Lucky Diamond Rich, spent over 1000 hours in a tattoo parlor (that's about 40 days). The New Zealander is completely covered in tattoos, including the eyelids, the skin between the toes, the ears and even the gums. He also replaced his teeth with shiny silver ones. Not content with having 100 percent of his body covered in tattoos, Rich began to redo the black tattoos for white ones.

10. Cat Man

Indian Dennis Avner decided to devote himself completely to his totem - a cat and turn into him. He got numerous tattoos, piercings, implants that allowed him to "wear a mustache", reshaped his face, surgically pointed his ears and sharpened his teeth. While most freaks are on shows, Avner works as a programmer. One of the most visually unusual people on the planet, a US Navy veteran was found dead in his Nevada home in November 2012.

Continuing the theme, with which lovers of wearable drawings decorated their bodies.

culture

Increasingly, these days you can hear about new diseases that used to be scary even to imagine.

These terrifying illnesses of a very dubious origin frighten us and make us thank fate for the fact that most of us have only had the flu and a sore throat.

There are dozens, hundreds of different exotic diseases that not only kill a person, but slowly make a cripple out of him. Here is a list of the most terrible diseases that pose a serious danger to people.

Fortunately, this disease disappeared many years ago.

What is known about it is that in the early 19th century, match industry workers were exposed to huge amounts of white phosphorus, a highly toxic substance that eventually provoked terrible jaw pain.

After some time, the jaw cavity filled with pus, and simply rotted. From the huge amount of phosphorus that the body received, the jaw even glowed in the dark.

If the bone was not removed surgically, phosphorus continued to destroy the body, which ultimately led to the death of the patient.

This disease occurs when the pituitary gland produces an excess of growth hormone. As a rule, this disease occurs in victims of benign tumors.

Acromegaly is characterized not only by huge growth, but also by a convex forehead, as well as a large gap between the teeth.

The most famous case of such a disease was found in Andre the Giant. As a result of this disease, his height reached 2.2 meters.

The weight of the poor fellow was 225 kg. If acromegaly is not treated in time, the heart cannot withstand such heavy loads associated with increased body growth. André the Giant died of heart disease at the age of 46.

Leprosy is perhaps one of the most terrible diseases known to medicine. The disease is caused by a special bacterium that destroys the skin.

A patient with leprosy, in the literal sense, begins to rot alive. As a rule, the disease affects, first of all, the face, hands, feet and genitals of a person.

Although the poor fellow does not lose all limbs, often the disease takes away the fingers and toes from the leper, and also destroys part of the face. Very often the nose suffers, as a result of which the face becomes terrible, and a shocking ragged hole appears in place of the nose.

The attitude towards lepers is also terrible. At all times, people with such an ailment were shunned, they were exiles from any society. And even in the modern world, there are entire settlements of lepers.

After contracting smallpox, the body is covered with a rash in the form of painful pimples. The disease is terrible because it leaves behind huge scars. Therefore, even if you manage to survive after this disease, the consequences are rather sad: scars remain all over your body.

Smallpox appeared a very long time ago. Experts have proven that even in ancient Egypt, people suffered from this disease. This is also evidenced by the mummies found by archaeologists.

It is known that at one time such famous personalities as George Washington, Abraham Lincoln, and Joseph Stalin were ill with smallpox.

In the case of the Soviet leader, the disease was especially acute, leaving behind obvious consequences on the face. Stalin was embarrassed by the scars on his face and always asked to retouch the photographs in which he was captured.

Porphyria is a genetic disease that leads to the accumulation of porphyrins (organic compounds with different functions in the body, they also produce red blood cells).

The disease affects the entire body, primarily the liver suffers. This disease is also dangerous for the human psyche.

People suffering from this skin condition should limit themselves to sun exposure, which can aggravate their overall health. It is believed that it was the existence of patients with porphyria that gave rise to legends about vampires and werewolves.

And soon a tiny and harmless bite turns into an ugly purulent ulcer. Therefore, bites to the face are especially dangerous. It takes a long time before the wounds heal.

Without proper treatment, a person can die. Many people in Afghanistan suffer from this disease.

The disease is common in tropical regions of Africa, more than a hundred million people suffer from elephantiasis. Victims of this disease experience frequent headaches and nausea.

The most effective means in the fight against the disease are special antibiotics. In the worst and most advanced cases, the patient cannot avoid surgical intervention.

Minor cuts and abrasions are part of our lives. And they're pretty harmless as long as there aren't any flesh-eating bacteria around. Then, in a matter of seconds, a small wound can become life-threatening.

Bacteria eat away at living flesh, and only the amputation of certain tissues can stop the spread of the disease. Treat the patient with antibiotics. However, even despite intensive treatment, 30-40 percent of all cases of the disease end in death.

human teeth

Tooth consists mainly of dentin with a cavity, covered on the outside with enamel and cement. The tooth has a characteristic shape and structure, occupies a certain position in the dentition, is built from special tissues, has its own nervous apparatus, blood and lymphatic vessels. Normally, a person has from 28 to 32 teeth. The absence of third molars, called “wisdom teeth”) is the norm, and the 3rd molars themselves are already considered an atavism by an increasing number of scientists, but this is currently a moot point.

Inside the tooth is loose connective tissue, permeated with nerves and blood vessels (pulp). Distinguish milk and permanent teeth - temporary and permanent bite. In temporary bite there are 8 incisors, 4 canines and 8 molars - a total of 20 teeth. The permanent bite consists of 8 incisors, 4 canines, 8 premolars and 8-12 molars. In children, milk teeth begin to erupt at the age of 3 months. Between the ages of 6 and 13, milk teeth are gradually replaced by permanent ones.

In rare cases, additional, supernumerary teeth (both milk and permanent) are observed.

Tooth structure

Dental anatomy is a branch of anatomy that deals with the structure of teeth. The development, appearance, and classification of teeth are the subject of this section, but occlusion or tooth contact is not. Dental anatomy can be considered as a taxonomic science, as it deals with the classification of teeth, their structure and naming. This information is then put into practice by dentists during treatment.

The tooth is located in the alveolar process of the upper jaw or in the alveolar part of the lower jaw, and consists of a number of hard tissues (such as tooth enamel, dentin, dental cement) and soft tissues (dental pulp). Anatomically, the crown of the tooth (the part of the tooth protruding above the gum), the root of the tooth (the part of the tooth located deep in the alveolus, covered by the gum) and the neck of the tooth are distinguished - the clinical and anatomical necks are distinguished: the clinical neck corresponds to the edge of the gum, and the anatomical is the place where the enamel passes into the cement, which means that the anatomical neck is the actual site of transition of the crown to the root. It is noteworthy that the clinical neck shifts with age towards the root apex (apex) (since gum atrophy occurs with age), and the anatomical neck moves in the opposite direction (since the enamel becomes thinner with age, and in the neck area it can be completely worn out due to the fact that in the region of the neck, its thickness is much less). Inside the tooth there is a cavity, which consists of the so-called pulp chamber and the root canal of the tooth. Through a special (apical) opening located at the top of the root, arteries enter the tooth, which deliver all the necessary substances, veins, lymphatic vessels, which ensure the outflow of excess fluid and participate in local defense mechanisms, as well as nerves that innervate the tooth.

Embryology

Orthopantomogram of teeth

The development of teeth in the human embryo begins at about 7 weeks. In the area of ​​future alveolar processes, a thickening of the epithelium occurs, which begins to grow in the form of an arcuate plate into the mesenchyme. Further, this plate is divided into anterior and posterior, in which the rudiments of milk teeth are formed. Tooth germs gradually separate from the surrounding tissues, and then the components of the tooth appear in them in such a way that epithelial cells give rise to enamel, dentin and pulp are formed from the mesenchymal tissue, and cement and root sheath develop from the surrounding mesenchyme.

Tooth regeneration

X-ray (from left to right) of the third, second and first molars in various stages of development

Human teeth do not regenerate, while in some animals, such as sharks, they are constantly updated throughout life.

In a recent study led by G. Fraser from the University of Sheffield, the influence of various genes on the formation of the dental plate in humans and sharks (in which teeth grow continuously throughout life) was studied. The group was able to identify a clear set of genes responsible for tooth differentiation and growth. It turned out that these genes in humans and sharks are largely identical, but in humans, after the formation of molars, for unknown reasons, the plate is lost. Scientists believe that the discovery of the genes responsible for the growth of teeth will serve as the first step in the search for the possibility of their regeneration.

Biochemistry of teeth

Tooth structure

Teeth (Latin dentes) are organs that are located in the alveolar processes of the upper and lower jaws and perform the function of primary mechanical processing of food. The jaws of an adult contain 32 permanent teeth. In their structure, dental tissues are close to bone tissue, the main structural and functional components of the tooth are derivatives of connective tissue.

In each tooth, there is a crown of the tooth (corona dentis), which protrudes freely into the oral cavity, the neck of the tooth covered by the gums and the root of the tooth (radix dentis) fixed in the bone tissue of the alveoli, which ends with an apex (apex radicis dentis).

Comparative characteristics of biochemical
composition of dental tissues.

Tooth stone.

The tooth is built from three balls of calcified tissues: enamel, dentin, and cementum. The cavity of the tooth is filled with pulp. The pulp is surrounded by dentin, the underlying calcified tissue. On the protruding part of the tooth, the dentin is covered with enamel. The roots of the teeth sunk into the jaw are covered with cementum.

The roots of the teeth, which are immersed in the alveolar sockets of the upper and lower jaws, are covered with periodontium, which is a specialized fibrous connective tissue that holds the teeth in the alveoli. The main periodontium is made up of periodontal ligaments (ligaments), which connect the cementum with the bone matrix of the alveolus. From a biochemical point of view, periodontal ligaments are based on type I collagen with some type III collagen. Unlike other ligaments of the human body, the ligamentous apparatus that forms the periodontium is highly vascularized. The thickness of the periodontal ligaments, which in an adult is approximately 0.2 mm, decreases in the elderly and senile age.

These components of the tooth differ in functional purposes and, accordingly, in biochemical composition, as well as in metabolic features. The main components of tissues are water, organic compounds, inorganic compounds and mineral components, the content of which can be given in the following tables:

(% wet weight of the woven component):

NECROSIS OF THE TEETH

Biochemical composition of human tooth tissues
(% dry weight of the fabric component):

Remineralization of teeth.

Organic components of the tooth

Leave your teeth cleaning to the professionals.

The organic components of the tooth are proteins, carbohydrates, lipids, nucleic acids, vitamins, enzymes, hormones, organic acids.

The basis of the organic compounds of the tooth, of course, are proteins, which are divided into soluble and insoluble.

Soluble proteins of dental tissues:

Named tooth decay
caries, begin by dissolving
minerals in the tooth.

albumins, globulins, glycoproteins, proteoglycans, enzymes, phosphoproteins. Soluble (non-collagenous) proteins are characterized by high metabolic activity, perform enzymatic (catalytic), protective, transport and a number of other functions. The highest content of albumins and globulins is in the pulp. The pulp is rich in enzymes of glycolysis, the tricarboxylic acid cycle, the respiratory chain, the pentose phosphate pathway for carbohydrate digestion, and protein and nucleic acid biosynthesis.

Soluble enzyme proteins include two important pulp enzymes - alkaline and acid phosphatases, which are directly involved in the mineral metabolism of tooth tissues.

It manifests itself and is characterized by inflammation of the soft tissues and mucous membranes.

Biochemical characteristics of individual
tissue components of the tooth

Enamel

Enamel is the hardest tissue in the human body.
95% mineral.

the hardest mineralized tissue that sits on top of the dentin and outwardly covers the crown of the tooth. Enamel makes up 20-25% of the dental tissue, the thickness of its ball is maximum in the area of ​​chewing peaks, where it reaches 2.3-3.5 mm, and on the lateral surfaces - 1.0-1.3 mm.

The high hardness of the enamel is due to the high degree of tissue mineralization. Enamel contains 96% minerals, 1.2% organic compounds and 2.3% water. Part of the water is in a bound form, forming a hydration shell of crystals, and part (in the form of free water) is filled with microspaces.

The main structural component of enamel are enamel prisms with a diameter of 4-6 microns, the total number of which ranges from 5 to 12 million, depending on the size of the tooth. Enamel prisms are composed of packed crystals, often hydroxyapatite Ca8H2(PO4)6×5H2O. Other types of apatite are poorly represented: hydroxyapatite crystals in mature enamel are approximately 10 times larger than crystals in dentin, cementum, and bone tissue.

As part of the mineral substances of enamel, calcium is 37%, phosphorus - 17%. The properties of enamel largely depend on the ratio of calcium and phosphorus, which changes with age and depends on a number of factors. In adult tooth enamel, the Ca/P ratio is 1.67. In the enamel of children, this ratio is lower. This indicator also decreases with enamel demineralization.

Dentien

These buildups of tartar cause the gum surfaces to recede and the soft dentinal material that covers the roots of the teeth begins to break down.

mineralized, acellular, avascular tissue of the tooth, which forms the bulk of its mass and in structure takes an intermediate position between bone tissue and enamel. It is harder than bone and cement, but 4-5 times softer than enamel. Mature dentin contains 69% inorganic substances, 18% organic and 13% water (which is 10 and 5 times more than enamel, respectively).

Dentin is built from mineralized intercellular substance, pierced by numerous dentinal canals. The organic matrix of dentin makes up about 20% of the total mass and is close in composition to the organic matrix of bone tissue. The mineral basis of dentin is made up of apatite crystals, which are deposited in the form of grains and spherical formations - calcospherites. Crystals are deposited between collagen fibrils, on their surface and within the fibrils themselves.

dental pulp

it is a highly vascularized and innervated specialized fibrous connective tissue that fills the pulp chamber of the crown and root canal. It consists of cells (odontoblasts, fibroblasts, microphages, dendritic cells, lymphocytes, mast cells) and intercellular substance, and also contains fibrous structures.

The function of the cellular elements of the pulp - odontoblasts and fibroblasts - is the formation of the main intercellular substance and the synthesis of collagen fibrils. Therefore, cells have a powerful protein-synthesizing apparatus and synthesize a large amount of collagen, proteoglycans, glycoproteins and other water-soluble proteins, in particular, albumins, globulins, and enzymes. In the dental pulp, a high activity of carbohydrate metabolism enzymes, tricarboxylic acid cycle, respiratory enzymes, alkaline and acid phosphatase, etc. was found. The activity of enzymes of the pentose phosphate pathway is especially high during the period of active production of dentin by odontoblasts.

The pulp of the tooth performs important plastic functions, taking part in the formation of dentin, provides trophism of the dentin of the crown and root of the tooth. In addition, due to the presence of a large number of nerve endings in the pulp, the pulp provides the necessary sensory information to the central nervous system, which explains the very high pain sensitivity of the internal tissues of the tooth to pathological stimuli.

Processes of mineralization-demineralization -
the basis of mineral metabolism of tooth tissues.

The basis of the mineral metabolism of tooth tissues are three interdependent processes that constantly occur in the tissues of the tooth: mineralization, demineralization and remineralization.

Mineralization of the tooth

this is the process of formation of an organic base, primarily collagen, and its saturation with calcium salts. Mineralization is especially intense during teething and the formation of hard tooth tissues. The tooth erupts with non-mineralized enamel!!! There are two main stages of mineralization.

The first stage is the formation of an organic, protein matrix. The pulp plays the leading role at this stage. In pulp cells, odontoblasts and fibroblasts, collagen fibrils, non-collagen proteins proteoglycans (osteocalcin) and glycosaminoglycans are synthesized and released into the cell matrix. Collagen, proteoglycans and glycosaminoglycans form the surface on which the formation of the crystal lattice will take place. In this process, proteoglycans play the role of collagen plasticizers, that is, they increase its swelling capacity and increase its total surface. Under the action of lysosomal enzymes, which are released into the matrix, proteoglycan heteropolysaccharides are cleaved to form highly reactive anions that are able to bind ions Ca2+ and other cations.

The second stage is calcification, deposition of apatites on the matrix. Oriented crystal growth begins at the points of crystallization or at the points of nucleation - in areas with a high concentration of calcium and phosphate ions. The locally high concentration of these ions is provided by the ability of all components of the organic matrix to bind calcium and phosphates. In particular: in collagen, the hydroxyl groups of serine, threonine, tyrosine, hydroxyproline and hydroxylysine residues bind phosphate ions; free carboxyl groups of dicarboxylic acid residues in collagen, proteoglycans and glycoproteins bind ions Ca2+ ; residues of g-carboxyglutamic acid of calcium-binding protein - osteocalcin (calprotein) bind ions Ca2+ . Calcium and phosphate ions are concentrated around the crystallization nuclei and form the first microcrystals.

Toothpastes

An increase in the concentration of the dispersed phase to the limiting possible value in aggregation-resistant suspensions leads to the formation of highly concentrated suspensions, which are called pastes. Like output suspensions, pastes are aggregatively stable in the presence of a sufficient amount of strong stabilizers, when the particles of the dispersed phase in them are well solvated and separated by thin films of liquid, which serves as a disperse medium. Due to the small part of the dispersion medium in the paste, all of it is practically bound in solvate films that separate the particles. The absence of a free sparse vase adds high viscosity and some mechanical strength to such systems. Due to the numerous contacts between the particles in the pastes, the formation of spatial structures can occur and thixotropy phenomena are observed.

The most widely used toothpastes. A bit of history. Our ancestors brushed their teeth with crushed glass, charcoal, and ash. Three centuries ago in Europe they began to brush their teeth with salt, then switched to chalk. Since the beginning of the 19th century, chalk-based tooth powders have been widely used in Western Europe and Russia. Since the end of the 19th century, the world began to switch to toothpaste in tubes. In the 20s of the last century, the search for a replacement for chalk as a dental abrasive began. These searches led to the use of silicon dioxide, which is highly compatible with fluorine compounds and other active ingredients, which have controlled abrasiveness, which makes it possible to create pastes with a wide range of properties. And finally, we got the optimal pH value = 7.

But even now, in some pastes, chalk with a reduced content of aluminum (Al), iron (Fe) and trace elements is used as an abrasive, but with an increased ability to erase.

In addition, some pastes include plantain, nettle and tree extracts, vitamins, ascorbic acid, pantothenic acid, carotenoids, chlorophyll, flavonoids.

All pastes are divided into two large groups - hygienic and therapeutic and prophylactic. The first group is intended only for cleansing the goiter from the plaque of food, as well as giving the oral cavity a pleasant smell. Such pastes are usually recommended for those who have healthy teeth, and also no reason for the occurrence of dental diseases, and who regularly visits the dentist.

The bulk of toothpastes belongs to the second group - therapeutic and prophylactic. Their purpose, in addition to cleaning the surface of the teeth, is to suppress the microflora that causes caries and periodontitis, remineralize tooth enamel, reduce inflammation in periodontal diseases, and whiten tooth enamel.

Allocate anti-caries pastes that contain calcium and fluoride toothpastes, as well as toothpastes with anti-inflammatory action and whitening pastes.

The anti-caries effect is provided by the presence of fluorides in the toothpaste (sodium fluoride, tin fluoride, aminofluoride, monofluorophosphate), as well as calcium (calcium glycerophosphate). The anti-inflammatory effect is usually achieved by adding herbal extracts (mint, shavlia, chamomile, etc.) to the toothpaste. Whitening pastes contain sodium bicarbonate, or soda, which has a pronounced abrasive effect. It is not recommended to use such pastes every day due to the risk of damage to the enamel. It is usually recommended to use them 1-2 times a week.

There is also a list of substances that are part of toothpastes. They perform auxiliary functions. So, detergents, among which sodium lauryl sulfate is more common, which is also used in the manufacture of shampoos, cause foaming. Abrasives, among which the most popular are aluminum hydroxide, chalk, sodium bicarbonate, silicon dioxide, clean the surface of the teeth from plaque and microbes. Acidity stabilizers are designed to increase the pH in the mouth because an acidic environment promotes cavities. Other substances that are part of toothpaste improve its consumer properties - thickeners, dyes, solutions, etc.

The main components of toothpastes:
1) abrasive substances;
2) detergents: soap used to be used, now sodium lauryl sulfate, sodium lauryl sarcosinate: the foaminess of the toothpaste and the surface of the tangent substances depend on this component;
3) glycerin, polyethylene glycol - provide elasticity and viscosity of pastes;
4) binders (hydrocolloids, sodium alginate, starch, thick juices, dextrin, pectin, etc.);
5) various additives (plant extracts, salts, etc.).

In the clinical practice of developed countries, synthetic hydroxyapatite is used as a bone tissue substitute. Reducing the sensitivity of teeth, protecting the surface areas of enamel, hydroxyapatite has anti-inflammatory properties, adsorbing microbial bodies, and ahead of the development of purulent-inflammatory processes. In addition, hydroxyapatite stimulates the growth of bone tissue (osteogenesis), provides micro-treatment of bone and dental tissues with calcium and phosphorus ions, “bricking up” microcracks in them. It has high biocompatibility, is devoid of immunogenic and allergic activity. Synthetic hydroxyapatite has very small particle sizes (0.05 microns). Such parameters greatly increase its biological activity, since the size of its molecules is comparable to the size of protein macromolecules.

An effective additive is triclosan, which acts on a wide range of bacteria, fungi, yeasts and viruses. The antimicrobial activity of triclosan is based on a violation in its presence of the activity of the cytoplasmic membrane and the leakage of cellular components of low molecular weight.

The composition of toothpastes also includes carbamide with components such as xylitol, sodium bicarbonate, which are therapeutic and prophylactic additives. This mixture neutralizes the action of acids, mainly lactic, which are produced by plaque bacteria by fermenting carbohydrates found in foods and drinks. Bacteria produce, although in much smaller quantities, other acids such as acetic, propionic, and butyric. The formation of acids leads to a decrease in the pH of plaque: at a pH of less than 5.5, the process of demineralization of tooth enamel begins. The longer the duration of such demineralization, the higher the risk of caries. Penetrating into plaque, urea neutralizes acids, being broken down by bacteria in the presence of the urease enzyme into CO2 and NH3 ; formed NH3 is alkaline and neutralizes acids.

General Functions of the Teeth

Mechanical processing of food
food retention
Participation in the formation of speech sounds
Aesthetic - are an important part of the mouth

Types and functions of teeth

According to the main function, teeth are divided into 4 types:
The incisors are the first teeth that erupt in children and are used to grasp and cut food.
Fangs - cone-shaped teeth that are used to tear and hold food
Premolars (small molars)
Molars (large molars) - the back teeth, which serve to grind food, often have three roots on the upper jaw and two on the lower

Tooth Development (Histology)

Hat stage

Beginning of the bell stage

Acid phosphatase

has the opposite, demineralizing effect. It belongs to lysosomal acid hydrolases, which enhance the dissolution (absorption) of both mineral and organic structures of tooth tissues. Partial resorption of tooth tissues is a normal physiological process, but it especially increases during pathological processes.

An important group of soluble proteins are glycoproteins. Glycoproteins are protein-carbohydrate complexes that contain from 3-5 to several hundred monosaccharide residues and can form from 1 to 10-15 oligosaccharide chains. Typically, the content of carbohydrate components in a glycoprotein molecule rarely exceeds 30% of the mass of the entire molecule. The glycoproteins of tooth tissues include: glucose, galactose, monose, fructose, N-acetylglucose, N-acetylneuraminic (sialic) acids, which do not have a regular rotation of disaccharide units. Sialic acids are a specific component of a group of glycoproteins - sialoproteins, the content of which is especially high in dentin.

One of the most important glycoproteins of the tooth, as well as bone tissue, is fibronectin. Fibronectin is synthesized by cells and secreted into the extracellular space. It has the properties of a "sticky" protein. By binding to the carbohydrate groups of sialoglycolipids on the surface of plasma membranes, it ensures the interaction of cells between themselves and the components of the extracellular matrix. Interacting with collagen fibrils, fibronectin ensures the formation of the pericellular matrix. For each compound with which it binds, fibronectin has its own, so to speak, specific binding site.

Insoluble proteins in dental tissue

are often represented by two proteins - collagen and a specific structural protein of enamel, which does not dissolve in EDTA (ethylenediaminetetraacetic) and hydrochloric acid. Due to its high stability, this enamel protein acts as the skeleton of the entire molecular architecture of enamel, forming a framework - a “crown” on the tooth surface.

Collagen: structural features,
role in tooth mineralization.

Collagen is the main fibrillar protein of connective tissue and the main insoluble protein in tooth tissues. As stated above, its content is about a third of all proteins in the body. Most collagen is found in tendons, ligaments, skin and tooth tissues.

The special role of collagen in the functioning of the human dentoalveolar system is due to the fact that the teeth in the holes of the alveolar processes are fixed by periodontal ligaments, which are formed precisely by collagen fibers. With scurbut (scurvy), which occurs due to a lack of vitamin C (L-ascorbic acid) in the diet, there are violations of the biosynthesis and structure of collagen, which reduces the biomechanical properties of the periodontal ligament and other periodontal tissues, and, as a result, loosen and fall out teeth. In addition, the blood vessels become brittle, multiple pinpoint hemorrhages (petechiae) occur. Actually, gum bleeding is an early manifestation of scorbut, and violations in the structure and functions of collagen are the root cause of the development of pathological processes in connective, bone, muscle and other tissues.

Carbohydrates of the organic matrix of the tooth
composition of dental tissues.

Periodontal disease is a systemic lesion of the periodontal tissue.

The composition of the organic matrix of the tooth includes the monosaccharides glucose, galactose, fructose, manose, xylose and the disaccharide sucrose. Functionally important carbohydrate components of the organic matrix are homo- and heteropolysaccharides: glycogen, glycosaminoglycans and their complexes with proteins: proteoglycans and glycoproteins.

homopolysaccharide glycogen

performs three main functions in the tissues of the tooth. First, it is the main source of energy for the processes of formation of crystallization nuclei and is localized in the places of formation of crystallization centers. The content of glycogen in the tissue is directly proportional to the intensity of mineralization processes, since a characteristic feature of tooth tissues is the prevalence of anaerobic processes of energy formation - glycogenolysis and glycolysis. Even with sufficient oxygen supply, 80% of the energy needs of the tooth are covered by anaerobic glycolysis, and, accordingly, by the breakdown of glycogen.

Secondly, glycogen is a source of phosphate esters of glucose - substrates of alkaline phosphatase, an enzyme that splits off phosphoric acid ions (phosphate ions) from glucose monophosphates and transfers them on a protein matrix, that is, initiates the formation of an inorganic matrix of the tooth. In addition, glycogen is also a source of glucose, which is converted into N-acetylglucosamine, N-acetylgalactosamine, glucuronic acid and other derivatives that take part in the synthesis of heteropolysaccharides - active components and regulators of mineral metabolism in tooth tissues.

Heteropolysaccharides of the organic matrix of the tooth

represented by glycosaminoglycans: hyaluronic acid and chondroitin-6-sulfate. A large number of these glycosaminoglycans remain in a protein-bound state, forming complexes of varying degrees of complexity, which differ significantly in the composition of the protein and polysaccharides, that is, glycoproteins (there is much more of a protein component in the complex) and proteoglycans, which contain 5-10% protein and 90- 95% polysaccharides.

Proteoglycans regulate the processes of aggregation (growth and orientation) of collagen fibrils, and also stabilize the structure of collagen fibers. Due to their high hydrophilicity, proteoglycans play the role of plasticizers in the collagen network, increasing its ability to stretch and swell. The presence of a high amount of acidic residues (ionized carboxyl and sulfate groups) in the molecules of glycosaminoglycans determines the polyanionic nature of proteoglycans, a high ability to bind cations and thereby take part in the formation of nuclei (centers) of mineralization.

An important component of tooth tissues is citrate (citric acid). The content of citrate in dentin and enamel is up to 1%. Citrate, due to its high ability to complex formation, binds ions Ca2+ , forming a soluble transport form of calcium. In addition to tooth tissues, citrate provides the optimal calcium content in blood serum and saliva, thereby regulating the rate of mineralization and demineralization processes.

Nucleic acids

found mainly in the dental pulp. A significant increase in the content of nucleic acids, in particular RNA, is observed in osteoblasts and odontoblasts during the period of tooth mineralization and remineralization and is associated with an increase in protein synthesis by these cells.

Characterization of the mineral matrix of the tooth

The mineral basis of tooth tissues is made up of crystals of various apatites. The main ones are hydroxypatite Ca 10 (PO4 )6 (OH)2 and octalcium phosphate Ca 8 H2 (PO4 )6 (OH)2× 5H 2 O . Other types of apatite that are present in the tissues of the tooth are listed in the following table:

Separate types of tooth apatites differ in chemical and physical properties - strength, ability to dissolve (destroy) under the action of organic acids, and their ratio in the tissues of the tooth is determined by the nature of nutrition, the provision of the body with microelements, etc. Among all apatites, fluorapatite has the highest resistance. The formation of fluorapatite increases the strength of enamel, reduces its permeability and increases resistance to cariogenic factors. Fluorapatite is 10 times worse soluble in acids than hydroxyapate. With a sufficient amount of fluoride in the human diet, the number of cases of caries is significantly reduced.

Oral hygiene

Main article: Teeth cleaning
Hygiene oral cavity is a means of preventing dental caries, gingivitis, periodontal disease, bad breath from the mouth (halitosis) and other dental diseases. It includes both daily cleaning and professional cleaning performed by a dentist.
This procedure involves the removal of tartar (mineralized plaque) that can form even with thorough brushing and flossing.
To care for the first teeth of a child, it is recommended to use special dental wipes.
Items for personal hygiene of the oral cavity: toothbrushes, dental floss (flos), tongue scraper.
Hygiene products: toothpastes, gels, rinses.

Enamel is not capable of regeneration. It has an organic matrix on which inorganic apatites seem to be attached. If apatites are destroyed, then with an increased supply of minerals they can be restored, but if the organic matrix is ​​destroyed, then restoration is no longer possible.
When teething, the crown of the tooth is covered on top with a cuticle, which soon wears out without doing anything useful.
The cuticle is replaced by a pellicle - a dental deposit, consisting mainly of saliva proteins, which have an opposite charge to enamel.
The pellicle performs a barrier (skip of mineral components) and cumulative (accumulation and gradual release of enamel calcium) function.
The role of the pellicle in the formation of dental plaque (helps to attach) with the further occurrence of caries is noted.

See also

animal teeth
dental formula
Tooth Fairy
Thirty-three (film)
Dental prosthetics(8, 9, 10, 11) are divided depending on the functions they perform: incisors (11), canines (10), small molars (9), large molars (8). Teeth appear in a person twice in a lifetime, the first ones are milk teeth, they appear in babies from six months to two years, there are only 20 of them. The second time teeth appear in children at the age of 6-7 years, and wisdom teeth after 20 years, there are only 32 of them.

The elastic should be tight enough so that the flashlight does not spontaneously come off from the recoil of a shot or when pulled out of the grass.

The described mounting system is in a sense universal - the installation location can be chosen based on personal preferences. On pneumatics, the bracket can be fastened with winding, clamps, and other methods.

If you make a special lodgement, for example, on the forearm, then the mount can be installed on it. In this case, so that there are no hooks, it is better to use the “mother” on the gun and the lodgement. The result will be a universal lighting system, with the ability to quickly rearrange it to the right “now” place.

The design has been tested in operation and proved to be the best.

(lat. aa. vv. et nn alveolares)

This is a large number of arteries, veins, vascular connections, which are collected in one plexus. The alveolar neurovascular bundle is located at the bottom of the jaw. Processes connects with all teeth.

Apical foramen

(lat. apical foramen)

These are two gaps between the canals of the root of the tooth, located at the top, through which the nerve endings and blood vessels of the alveolar neurovascular bundle pass and enter the middle of the tooth cavity. The apical foramina, which are also called apical foramina, are closed in the treatment of nerve inflammation.

Teeth channels

(lat. canalis radicis dentis)

Tooth canals are small formations that run through the entire root. They have a complex anatomy, which also complicates their treatment. You can find out how many canals are in a tooth by its location: 1, 2, 3 have only one, all the rest have from 1 to 4.

dental nerve

(lat. nervae)

The nerve of the tooth passes through the entire root and cavity of the crown. It looks like a small soft thread. As a rule, there are as many nerve processes in a tooth as there are canals.

Periodontium

(lat. periodontium)

The periodontium of a tooth is the connective tissue inside the root. The structure of the periodontium includes collagen and oxytalan (elastic) fibers, which are responsible for the rational distribution of the load.

tooth cavity

(lat. cavitas dentis)

The cavity inside the tooth has a root and crown part. This is the place where the connective tissue is located along with the nerves and blood vessels. There are many harmless bacteria in the cavity of the tooth.

Pulp

(lat. pulpa dentis)

The dental pulp is the pulp inside the cavity of the crown. The structure of the pulp is as follows: the cellular part, the ground substance, fibers, vessels and nerves. The pulp nourishes the tooth and connects with its other tissues.

Veins of the tooth

Dental veins are very small blood vessels that carry blood to the heart. Thus, the veins, together with the arteries, are responsible for the nutrition of the tooth and its proper metabolism.

tip of the tooth

(lat. apex radicis dentis)

The tip of the tooth (anatomical) is the ending on the root, which has an apical opening where the vessels and nerves pass. The physiological apex of the root is the narrowest section of the canal.

Teeth in a person's life change only twice. For the first time, they are represented by milk teeth, which are very soft and porous in structure, through which the infection can quickly spread throughout the body. Milk teeth quickly deteriorate, become covered with carious spots, which subsequently develop into pulpitis and periodontitis. Milk teeth are whiter than permanent teeth and smaller in size.

Permanent teeth completely replace milk teeth by the age of 15-16. Then, over the years, they can be supplemented.

The uppermost dental “shell”, which is visible to every person when talking and smiling, is called enamel tooth. It is the hardest and densest tissue of the tooth. But it's not a uniform fabric, like icing. Enamel consists of prisms and interprismatic substance. It covers only the coronal part of the tooth, which protrudes above the gum.

Under the enamel dentine tooth. It is softer than enamel, in color it is represented by various yellowish shades. It consists of dentinal tubules, in the center of which nerve fibers pass, transmitting nerve impulses from the enamel to the tooth pulp. Dentin makes up the entire "body" of the tooth, including the roots. With thinning of the tooth enamel, a partial exposure of the dentin occurs, which is accompanied by the appearance of dark yellow spots and stripes and the formation of.

Under the gum, the roots of the tooth are covered cement. It is part of the periodontium of the tooth, which consists of cement, periodontal ligaments, jaw bones.

Inside the tooth is pulp- accumulation of blood, lymphatic vessels and nerve fibers. It nourishes the tooth and produces a response to various stimuli.

Now let's talk about the anatomical structure of the tooth.

The outer surface consists of their crowns. All teeth have an anterior surface (vestibular, labial or buccal), internal (lingual or palatal), distal (far from the center of the face) and mesial (located closer to the center of the face). The front teeth also have a cutting edge, and the side teeth have a chewing surface.

The root of the tooth is hidden under the gum. Many people think that the tooth is in the gum, but it is not. In fact, the tooth is in the bone, in the dental alveolus. In the bone, the tooth is held by the periodontal ligaments, which are stretched like ropes between the wall of the alveolus and the cementum of the tooth. Closer to the top of the root there is a hole through which nerves and vessels exit the pulp. The roots of the teeth can be from one to three or four in standard situations. But there are exceptions, when their number can reach six.

Between the crown of the tooth and the root there is a neck of the tooth. It is represented by a narrowing of the crown closer to the gum. In its place is the connection of enamel and cement.