The location of the upper teeth in humans. Features of the structure of the teeth

Dental apparatuses of prehistoric and modern man differ significantly. Ancient people had more than 36 teeth, advanced fangs and a massive jaw. This was due to the need to chew rough food and raw meat. With the addition of thermally processed foods to the diet, the dentition began to change. The fangs were the first to transform, standing in the bite line. Then the jaw arch narrowed, the interdental spaces disappeared, and the teeth themselves decreased in size. Currently, 32 teeth in humans are the norm, but third molars are considered to be atavism.

Interesting fact!

The teeth of an ancient person cannot be called aesthetic, but they were distinguished by health. According to scientists, cavemen never suffered from caries and other oral diseases.

Name of human teeth

Depending on the location and structure, dental units have their own functional features and are called differently.

Incisors. On both jaws there are four front teeth in humans - medial and lateral incisors, which serve to bite off food.
Fangs. Sharp teeth designed for chewing hard foods.
Premolars."Fours" and "fives" on the left and right sides of each jaw arch grind soft or small pieces of food.
Molars. Three large outer teeth in each row are aimed at grinding coarse substances.
fangs and the incisors are included in the anterior group, or "smile zone", the molars of a person - in the chewing segment.

In addition, teeth are divided into temporary and permanent. In the first case, we are talking about dairy, which appear in children from the fifth month of life to three years. In the second, the final bite is implied, which is formed in the period from six to thirteen years. Milk teeth differ from permanent teeth only in size, and in structure they are identical.

How many teeth does a person have?

The number of teeth in a person depends on age and anatomical features. The child has a set of 20 milk teeth, which are replaced by a permanent bite of 28 teeth. The third molars erupt, as a rule, after twenty years or do not grow at all, which is not a pathology.

In dentistry, a single numbering of human teeth is adopted. Doctors classify the teeth as lower and upper, distinguish the right and left segments of the jaws. Each of them includes two incisors, a canine, two premolars and three molars. The countdown starts from the first front tooth and ends, respectively, with the “eight”. Sometimes a number is added to the serial number indicating the location area. For example, the right canine of the top row is numbered 13. This order in a schematic representation is called the formula of human teeth.

Polyodontia

In rare cases, there is such an anomaly as polyodontics - supernumerary, or extra teeth in a person. Dental units can appear in the milk and permanent occlusion anywhere in the jaw, isolated or fused with the main teeth. The defect affects not only the aesthetics of the smile, but also leads to the formation of incorrect occlusion, worsens the quality of chewing food, diction. Most often, supernumerary teeth are removed or built into the dentition in childhood.

Adentia

There is also a deviation opposite in meaning called adentia - congenital or acquired absence of dental units. The causes of the phenomenon include heredity or improper development of the embryo in the womb. People without teeth cannot fully eat and talk, have a deformed facial contour and weakened immunity.

human teeth dimensions

The upper central incisors are twice as wide as their antagonists. The remaining dental units of the same name have approximately equal parameters. The size is determined using special tables with the optimal value and tolerances. Experienced doctors calculate proportions by dividing the length of a person's teeth by their width. A result of about 0.75 millimeters is considered close to ideal. For a more detailed diagnosis, other professional formulas and methods are used.

Size deviations from the norm occur due to improper jaw formation, fusion of tooth buds, or genetic predisposition. Teeth that are too large are called macrodentia, abnormally small teeth are called microdentia. Pathologies are accompanied by malocclusion and chewing functions, however, they are successfully corrected by the dentist.

Interesting fact!

The longest tooth in the world belongs to an Indian teenager. The size of his crown is almost four centimeters. About a year ago, the tooth was removed, and the young man got into the Guinness Book of Records.

Human tooth structure

Anatomy

From the point of view of anatomy, a human tooth consists of three parts.

Crown. Visible part protruding above the gum. It has four sides: occlusive, or cutting edge, in contact with antagonist teeth; a contact wall adjacent to adjacent dental units; vestibular and lingual surfaces facing the lips and tongue, respectively.
Root. It is fixed in the hole with connective tissue, located in the deepening of the jaw. As a rule, premolars have two roots, and molars have three, four or even five. The remaining dental units have one root canal.
Neck. It is located between the crown part and the root of a human tooth, surrounded by periodontium.

Histology

What are human teeth made of? Consider the structure of a human tooth in section.

Enamel. Transparent protective coating of the crown, almost entirely composed of inorganic trace elements.
Dentine. The hard base of the tooth, containing 80% mineral components and 20% organic matter. The shade of dentin is responsible for the color of the dental units, as it shines through the enamel.
Cement. Bone covering the tooth root. It plays the role of a fastener connecting the tooth with the alveolus.
Pulp. Soft tissue filled with bundles of nerves and capillaries. Painful sensations during caries are explained precisely by the presence of nerve endings.

Human "wisdom teeth"

"Wisdom tooth" - the third extreme molar, having from three to five roots. In structure, it is no different from the "neighbors". To the question "How many wisdom teeth does a person have?" cannot be answered unambiguously. They erupt around the age of twenty, one on each side of both jaws. However, there are people without wisdom teeth. This is a variant of the norm, since in the process of human evolution the need for the "eight" has disappeared, and the structure of the jaws has undergone corresponding changes. To date, the third molars are considered a vestigial organ.

Dental health and human health

The relationship between teeth and human organs is not obvious at first glance, but oral health directly affects the functioning of the whole organism.

GIT. Pathologies of the dentition reduce the quality of chewing food, disrupting digestion.
The immune system. Diseases of the oral cavity weaken the general immunity. As a result, it is difficult for the body to resist bacteria and viruses, especially active during epidemics.
Heart and blood vessels. Inflammation of the tissues of the oral cavity can be accompanied by suppuration, which, in turn, cause intoxication, causing heart failure and angina attacks.

The health of the dentition itself is affected by nutrition, stress, ecology and bad habits. The teeth of a smoker, for example, have a yellow coating and are prone to early loss.

The use of sweets provokes the development of caries - the destruction of hard dental tissues, starting with the demineralization of enamel. Poor dental care and untimely treatment contribute to the appearance of such inflammatory complications of this disease as pulpitis, periodontitis or tooth cyst.

Healthy human teeth provide not only the coordinated work of the whole organism, but also external attractiveness. Responsible attitude to oral hygiene, quitting smoking and regular visits to the dentist for preventive examinations will help to maintain a perfect smile for many years.

Teeth are an important part of the human speech and chewing apparatus. They take part in breathing and chewing, in the formation of voice and speech. Teeth are incapable of self-healing, and their strength is very apparent. Knowledge of the structure of the teeth helps a person to properly care for them and navigate the recommendations of dentists.

In dentistry, doctors use special numbering for diagnostics and ease of filling out a patient card.

It is customary to write down the arrangement of all teeth in the form of a special formula, which is called the dental formula.

In different systems, teeth or groups of teeth that perform the same functions are indicated by Roman or Arabic numerals and letters.

There are many systems for designating teeth. This is the standard Zsigmondy-Palmer system, and the universal alphanumeric system, and the Haderup system, and the international Viola system.

Photo: Designation of teeth according to the Zsigmondy-Palmer system

The Zsigmondy-Palmer (square-digit) system was adopted as early as 1876. Its principle is that the teeth of an adult are indicated by the usual Arabic numerals from 1 to 8, and in children by Roman numerals from I to V.

In the Haderup system, Arabic numerals are used to designate teeth, in the bottom row with a "-" sign, and in the top row with a "+" sign. Milk teeth are numbered from 1 to 5 with the addition of "0" and signs "-" and "+" by analogy with permanent teeth.

The universal alphanumeric system adopted by the ADA, the American Dental Association, is different in that each tooth in the dentition has its own number (in adults) or a letter (in children).

The countdown starts from the top right tooth to the left, and then in the bottom row from left to right.

Another dental formula might look like this:

where M is the molars, there are 3 of them in the dentition at the top and bottom on both sides, in total 12;
P - these are premolars, there are 2 of them, only 8;
C - fangs, 1 each, 4 in total;
I - incisors, 2 each, 8 in total.

We do a simple mathematical calculation and get 32 teeth, 8 in each of the 4 segments.

In 1971, the two-digit Viola system was adopted by the International Federation of Dentists. According to this system, the upper and lower jaws are divided into 4 quadrants (each into two) of 8 teeth. In adults, these are 1, 2, 3, and 4 quadrants, and in children, 5, 6, 7, and 8.

The quadrant number is indicated by the first digit, and the tooth number (from 1 to 8) is indicated by the second digit.

This system is the most convenient to use, due to the lack of lines and letters. Therefore, in the dentist's office, you can hear that you need to treat 33 or 48 teeth, and the child is 52 or 85, for example, this does not mean at all that you have 48 of them, and the child has 85.

Photo: Designation of teeth according to the Viola system

Dental crowns in the jaw form a slender dentition. Distinguish between the upper dentition and the lower. Each of these rows normally contains 16 teeth. The human dentition is symmetrical, it is divided into the right and left halves. Teeth that perform the same functions are designated by the same serial number.

Lower jaw

On the lower jaw, the teeth are indicated by 4 (right) and 3 ten (left).

41 and 31 - front lower incisors, they are also called central or medial;
42 and 32 - lateral (lateral) lower incisors,;
43 and 33 - lower fangs;
44, 45, 34 and 35 - lower premolars or small chewing teeth;
46, 47, 48, 36, 37 and 38 - lower molars or large chewing teeth.

upper jaw

On the upper jaw on the right, the teeth are marked with the first ten, and on the left - with the second.

11 and 21 - front upper incisors
12 and 22 - lateral upper incisors;
13 and 23 - upper fangs;
14, 15, 24 and 25 - upper premolars or small chewing teeth;
16, 17, 18, 26, 27 and 28 - upper molars or large chewing teeth.

The internal structure of the tooth

Depending on the function performed, the teeth have a different shape, but they are all similar in structure.

On top of each tooth is covered with enamel. It is the strongest and hardest tissue in the human body. In terms of strength, it is practically not inferior to diamond, since more than 96% consists of mineral calcium salts.

Enamel is formed by prisms and interprism matter. Outside, it is covered with a strong thin shell - the cuticle, which eventually wears off on the chewing surface of the teeth.

Under the enamel is dentin. It forms the basis of the tooth. It is highly mineralized bone tissue. It is highly durable, and second only to enamel in this regard.

Dentin surrounds the cavity of the tooth and the root canal. From the central tissues of the tooth to the enamel, the dentin is permeated with microscopic tubules, through which metabolic processes and the transmission of a nerve impulse are carried out.

Photo: 1 - raincoat dentine; 2 - peripulpal dentin; 3 - predentin; 4 - odontoblasts; 5 - dentinal tubules

In the area of the root, the dentin of the tooth is covered with cement, penetrated by collagen fibers. Fibers of the ligamentous apparatus - periodontium - are attached to the cement.

The internal cavity is filled with loose soft tissue - dental pulp. It is located in the crown of the tooth and in the root. It contains many blood and lymphatic vessels and nerves.

The pulp performs very important functions: tooth nutrition and metabolism. After the pulp is removed, the metabolic processes stop.

This is the histological structure of the tooth, and the anatomical diagram of the structure of human teeth shows us that they consist of a neck, crown and root.

Crown

The crown is the part of the tooth that protrudes above the gum.

Dental crowns have several different surfaces:

the contact surface with a similar or paired tooth on the opposite jaw is called occlusion,
the facial or vestibular surface faces the cheek or lips,
lingual or lingual surface facing the oral cavity,
the proximal or contact surface is the side facing other adjacent teeth.

Neck

The neck of the tooth connects the crown and root.

This is a slightly narrowed part of the tooth. Connective tissue fibers are located horizontally around the neck of the tooth, forming a circular ligament of this tooth.

Root

The root is located in a small depression - the dental alveolus.

The root ends with a tip, on which there is a small hole. It is through this opening that the vessels that feed the tooth and nerves pass. In total, a tooth can have several roots.

The incisors, premolars of the lower jaw and canines have one each. The molars of the lower and premolars (small molars) of the upper jaw have 2 of them. And the molars (large molars) of the upper dentition have 3 of them. In some cases, the tooth may even have 4 or 5 horses. Canines have the longest root.

The root and neck of the tooth with the jaw (the bone surface of the alveoli) are connected by connective tissue fibers that act as a ligamentous apparatus. That is why the tooth is so securely fixed in the alveolus.

And the space between the surface of the alveoli and the root of the tooth, called the periodontium, separates the circular ligament of the tooth from the oral cavity.

Video: human tooth structure

Both histologically and anatomically, milk teeth are very similar to permanent teeth.

But there are still some differences.

Milk teeth have a smaller crown.
The thickness of enamel and dentin in milk teeth is much less.
Milk tooth enamel is less mineralized.
The volume of the pulp and root canal in milk teeth is greater than in permanent ones.

Different types of teeth

With the front teeth - incisors - we bite off food. For convenience, they have a flat shape and sharp edges. The fangs help to tear off pieces of food and separate them.

Chewing teeth are essential for chewing food. For this, premolars (small chewing teeth) have 2 tubercles, and large ones have 4.

Sixes, or teeth No. 16, 26, 36 and 46 play an important role in closing the jaws, as they rest against each other and are limiters. As a result, they are under enormous stress. Eights are also called simply wisdom teeth.

Incisors or front teeth

As mentioned above, a person normally has 8 incisors.

The two central incisors of the upper jaw are noticeably larger than the lateral ones, and on the lower jaw, on the contrary, the lateral ones are larger than the central ones.

The maxillary central incisor is the largest and has a chisel-shaped crown and one cone-shaped root. Its cutting edge initially has 3 tubercles, which are erased over time.

The lateral incisors of the upper jaw are very similar in shape to the central ones, but smaller in size. The smallest incisors are the central (first) incisors of the mandible. The root is thin and slightly shorter than that of the lateral (second) incisors of the lower jaw.

fangs

There are 2 canines on the upper and lower jaws.

The canines of the upper dentition are located immediately behind the second incisors. Together they form a dental arch, in the corner of which a transition from cutting to chewing teeth is formed.

The shape of the canine crown is cone-shaped. The cone tapers towards the cutting edge with one pointed tubercle. The canines of the lower jaw are similar in shape to the maxillary canines, but smaller and shorter.

The molars are divided into small and large, or they are also called premolars and molars.

In the dentition, a person has 8 premolars - small molars, 4 on each jaw, 2 on each side.

Premolars are present in the permanent bite, and they erupt in place of the fallen milk molars. Their main function is crushing food and crushing.

In their structure, they combined the features of molars and canines. They have a rectangular shape, on the chewing surface there are 2 tubercles and a fissure (groove) between them.

The premolars of the upper jaw are similar in shape, but the second premolar is smaller and has one root, and the first has two. The mandibular premolars are rounded. The second premolar is slightly larger than the first. Each has one root.

Behind the second premolars are the molars.

There are only 12 of them, 3 teeth on each of the two sides on the lower and upper jaws.

The first molars are the largest. The first and second large chewing teeth - the molars of the upper jaw have three roots. The first molars of the lower dentition are its largest teeth. The first and second molars of the mandible have 2 roots.

The structure of the wisdom tooth

The third molars of both the upper and lower jaws are very diverse in shape and the number of roots can be different. They are often called wisdom teeth.

Timing of wisdom teeth eruption varies from person to person. In some, they erupt very early, and due to various defects, they have to be removed. For others, wisdom teeth erupt later.

There are times when they don't come out at all. This is due to the fact that the human jaw continues to undergo changes, as the quality of food has improved significantly, and there is no need to have a powerful chewing apparatus.

A photo

It is much easier to understand the structure of a tooth if you see it in a photo or a detailed drawing.

The part of the tooth coming out of the gum - the crown can tell us a lot about the function of this tooth. If it is flat, it is an incisor; if it is sharp, it is a canine; if it is wide and rounded or rectangular, it is a chewing premolar or molar.

With age, the composition of the teeth and their structure undergo various changes. Since the human dental apparatus takes part in various physiological processes, its condition and health are very important for everyone.

Knowledge of the structure of teeth and their anatomical features helps us to properly care for them. Many people, thanks to this knowledge, have managed to overcome the fear of visiting the dentist. Most of the time, fear comes from ignorance.

Healthy teeth are an adornment of a person. A snow-white smile, even bite and pink gums indicate that a person has good health, and is generally considered a sign of success.

Why did it happen and why is the teeth given such attention?

Teeth are special bone formations that carry out the primary mechanical processing of food.

Since ancient times, a person has been accustomed to eat fairly hard food - the fruits of plants, cereals, meat.

Such food requires good effort to process, and therefore healthy teeth have always been an indicator that a person eats well and varied.

Diagram of the structure of human teeth

The structure of the human molar

The first thing you need to know about teeth is that these organs are the only ones in the human body that cannot be restored.

And their seeming fundamentality and reliability are very quickly violated by poor care and bad habits.

And if the primary, milk, teeth are fragile precisely because of their temporary purpose, then the indigenous ones are given to a person once and for life.

In general, all human teeth are divided into the following types:

incisors (central and lateral, also called medial and lateral);
fangs;
small molars, or premolars;
large molars, or molars (these also include wisdom teeth that grow in a person at a young or mature age).

Usually their location on both jaws is recorded using the so-called dental formula.

For milk and molars, it differs only in that milk teeth are usually indicated using Latin numerals, and molars - Arabic.

The dental formula of an average adult looks like this: 87654321 | 12345678.

The teeth are indicated by numbers - a person should have two incisors, one canine, 2 premolars and three molars on each side on each jaw.

As a result, we get the total number of teeth of a healthy person - 32 pieces.

In children who have not yet replaced their milk teeth, the dental formula looks different, because there are about 20 of them in total.

Usually milk teeth grow by 2.5-3 years, and by 10-11 they are already completely replaced by molars. Understand, maybe at different ages.

Not all people can boast a smile of 32 teeth. The so-called third molars, or wisdom teeth, can grow in adulthood, and then not all 4, but may even remain in their infancy for life, and then there will be 28 teeth in the mouth. What to do if a wisdom tooth hurts, read in.

At the same time, the structure of the teeth of the upper and lower jaws has its own differences.

The structure of the teeth of the upper jaw

central incisor- chisel-shaped tooth, with a flattened crown. It has one cone-shaped root. The part of the crown that faces the lips is slightly convex. There are three tubercles on the cutting edge, and it is somewhat beveled on the outside.

Two, or side incisor, also has the shape of a chisel and has three tubercles on the cutting edge, like the central incisor. But its cutting edge itself has the shape of a tubercle, due to the fact that the central, medial tubercle is most clearly expressed on it. The root of this tooth is flattened in the direction from the center to the periphery. Often its upper third has a backward deviation. From the side of the cavity of the tooth there are three horns of the pulp, corresponding to the three tubercles of the outer edge.

Fang- a tooth with a distinct convex front side. A groove runs along the lingual side of the canine, dividing the crown in two, with the half located further from the center having a large area. This tooth has one tubercle on the cutting part. It is she who gives the fang a completely recognizable shape. In many people, this shape closely resembles the similar teeth of predators.

Next on the upper jaw is first premolar, indicated by the number 4 on the dental formula. Unlike the canine and incisors, it has a prismatic shape with convex buccal and lingual surfaces. It also has two tubercles on the chewing surface - buccal and lingual, of which the first is much larger in size. Furrows pass between the tubercles of the tooth, which are interrupted by enamel rollers, not reaching the edge of the tooth. The root of the first premolar is flattened, but it already has a forked shape and is also divided into the buccal and lingual parts.

Second premolar has a similar shape to the previous tooth. It differs from the first premolar in a much larger area of the buccal surface of the tooth, as well as in the structure of the root. It is cone-shaped and compressed in the anteroposterior direction in the second premolar.

The largest tooth of the upper jaw is the first molar, or, as it is also called, the large molar. Its crown is like a rectangle, and the chewing surface is diamond-shaped. It has as many as four tubercles responsible for chewing food. An H-shaped fissure passes between the tubercles. This tooth has three roots, of which the palatine is straight and the most powerful, and the two buccal are flat and deviated in the anteroposterior direction.

second molar slightly smaller than the first one. It has a cubic shape, and the fissure between its tubercles resembles the letter X. The buccal tubercles of this tooth are better expressed than the lingual ones. But the roots of this tooth have the same shape and properties as its predecessor.

third molar, or a wisdom tooth, does not grow in everyone. In form and properties, it is similar to the second, the differences exist only in the form of the root. At the third molar, it is often a spliced short powerful trunk.

The structure of the teeth of the lower jaw

The names of the teeth of the lower jaw of a person generally coincide with their antagonists in the upper dentition. But their structure and properties have a number of differences.

The mandibular central incisor is the smallest tooth. Its labial surface is slightly convex, while its lingual surface is concave. In this case, the marginal ridge is weakly expressed. The three cusps of this tooth are weakly expressed, as are the margins. The root is very small, flat.

The lateral incisor is slightly larger than the central incisor, but still remains a small tooth. Its crown is very narrow, chisel-shaped, curved towards the lips. The cutting edge of this tooth has two angles - the medial one is sharper, and the lateral one is blunt. Root one, flat, has longitudinal grooves.

The canine of the lower jaw is similar to its upper counterpart. It also has a diamond shape, convex on the side of the tongue. But, unlike the upper canine of the same kind, this tooth has a narrower shape. All its faces converge on one central tubercle. The root of the tooth is flat, deflected inwards.

The first lower premolar has only two cusps. Its chewing surface is beveled towards the tongue. The shape of this tooth is rounded. The root of the first premolar is one, flat and slightly flattened laterally. Grooves run along its frontal surface.

The second premolar of the lower jaw is larger than the first one due to the fact that both of its tubercles are equally developed. They are located symmetrically, and the fissure between them has the shape of a horseshoe. This tooth has the same root as its predecessor.

The first molar has a cubic shape and as many as five tubercles for chewing food - three of them are located on the buccal side, and two more on the lingual side. Due to the number of tubercles, the fissure between them resembles the letter J. The first molar has two roots. The rear is slightly shorter than the front and has only one channel. There are already two canals at the anterior root - anterior cervical and anterior lingual.

The second molar of the lower jaw is similar to the first cubic shape of the crown and roots.

The third molar is also similar to them. Its main difference is in the variety of tubercles. There are a lot of types of their development in this wisdom tooth.

Anatomical structure of the tooth

This is with regard to the structure of the jaw and individual teeth. But the anatomical structure of the tooth implies the presence of the following parts:

crowns,
necks,
root.

Crown name the part of the tooth that is located above the gum. That is visible to everyone.

Tooth root located in the alveolus - a recess in the jaw. The number of knights, as becomes apparent from the previous sections of the article, is not always the same. The root is fixed in the alveolus with the help of connective tissue formed by bundles of collagen fibers. The neck is the part of the tooth that is located between the root and the crown.

If you look at the tooth in section, you can see that it consists of several layers.

Outside, the tooth is covered with the hardest tissue in the human body - enamel. In the teeth that have just appeared, it is still covered on top with a cuticle, which over time is replaced by a membrane derived from saliva - the pellicle.

Histological structure of the tooth

Under the enamel is a layer of dentin - the base of the tooth. In its cellular structure, it is similar to bone tissue, but in terms of properties it has a much larger margin of safety due to increased mineralization.

In the area of the root, where there is no enamel, the dentin is covered with a layer of cementum and penetrated by collagen fibers that hold the periodontium together.

Connective tissue is located in the very center of the tooth - pulp. It is soft, permeated with many blood vessels and nerve endings. It is her defeat by caries or inflammatory processes that causes the very unbearable toothache.

The structure of milk teeth in children

Despite the fact that milk teeth are smaller than molars, and their structure is different, they are very similar in shape and purpose.

The main difference is that they almost always have a smaller size than their native followers.

The crowns of milk teeth have enamel and dentin with a lower degree of mineralization than that of molars, and therefore are more susceptible to caries.

At the same time, the pulp in milk teeth occupies a larger volume than in molars, and is also more susceptible to all kinds of inflammation and disease processes.

Even on their surface, tubercles of the cutting and chewing parts are poorly expressed.

At the same time, the incisors of the milk teeth are more convex than those of the permanent ones, and the tops of their roots are bent to the labial side.

Also, all milk teeth are distinguished by not too long and strong roots, due to which the change of teeth in childhood is not too painful.

All these features of their structure lead to the fact that 80% of all pathologies associated with dentistry develop in childhood. Therefore, it is very important to monitor the sanitation of milk teeth from childhood in order to avoid problems with permanent ones in the future.

Teeth are a very complex system of the human body. They carry a huge burden throughout their lives. At the same time, each tooth has its own shape, the most suitable for its purpose, the number of tubercles designed for efficient food processing, its own root system and their location in the alveolus.

In addition, the internal structure of the teeth is also not simple. They consist of several layers that have their own purpose and properties.

In particular, tooth enamel is the hardest tissue in the entire body, which makes it easy to process food.

In general, despite the apparent strength, teeth are a very fragile system that requires constant care and attention to the processes taking place in them, due to the fact that of all human organs they are the only ones that do not have the ability to self-heal, and therefore timely sanitation will help preserve them. for a long time healthy, strong and beautiful.

Pictures, photos of the structure of a human tooth:

tooth anatomy

Is it true that baby teeth don't have roots? What is included in the concept of the anatomy of the dentition? What are tooth surfaces? How are dental organs arranged, what do they consist of? What are the differences between lower teeth and their antagonists? What does the clinical anatomy of the teeth look like? What is the vestibular surface? Answers to all questions of interest to the reader about their structure (with visual drawings and a detailed description) will be found in this article.

Why does a person need teeth?

Human teeth are independent organs. Without teeth, a full life is impossible. The vast majority of people believe that the only purpose of teeth is to participate in the grinding of pieces of food before they go for further processing in the human digestive system. In addition to the chewing function (that is, the mechanical processing of food), human teeth have several other tasks:

formation of an aesthetic and attractive image;
participation in the creation of a "framework" for a human face;
articulation and speech.

The number of teeth in a person and their location on the upper and lower jaw

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The child grows 20 temporary bite teeth - 10 lower and the same number on top. The number is due to the structural features of the jaw. However, by the age of 13-14, temporary units are replaced by permanent ones. Normally, 28 permanent teeth should erupt. At 18-25 years old, some people grow 3rd molars. Each jaw contains 14-16 teeth.
The lower teeth are characterized by the same names and functions as their antagonists. They are divided into several varieties, based on the structural features of the human tooth, the functions performed and the dislocation in the row. The formation of a bite, the prevention of the gradual exit of the roots from the alveoli and the grinding of food become possible due to the fact that each tooth has an antagonist in the opposite jaw.
The main types are:
Incisors. Front teeth shaped like a chisel. They have 1 root. In each of the jaws, a pair of central and lateral incisors erupt. The structure of the central teeth (incisors) of the upper jaw of a person is similar to the lateral ones, but the first ones are larger. With the teeth in the lower jaw, the opposite is true. You can see the teeth of this type in the photo for the article.
Fangs. There are 4 pieces in the dentoalveolar system. These teeth are wedge-shaped. Single root. The canine of the upper jaw, like its antagonist from among the lower teeth, has a cutting part, which is divided into mesial and distal halves, which converge at an angle. The crown of the canine of the upper jaw is larger than that of the “paired” one on the lower. The maxillary canine, like any of the third molars, can be impacted, but this is extremely rare.
Premolars. There are 8 premolars in the dentoalveolar structure - two pairs in each jaw. They are distinguished into distal (first) with a sharper shape of the chewing surface. Mesial (second) - these teeth have a flattened crown shape. They have 1 - 2 roots. The differences between the first and second pair of premolars can be seen in the photo.
Molars. There can be from 2 to 3 pairs in the top and bottom row. They perform a chewing function, they are distinguished by a rectangular shape of the teeth. The molars of the dentition on top have three roots, on the bottom - two, with the exception of the third molars - their number and location of roots is unpredictable. Typically, the maxillary first molars are the largest teeth. The lower teeth are usually smaller than the upper teeth, but have the same shape. A photo of molars is also presented above (more details in the article: molars: features of the structure of teeth).

The anatomical structure of the teeth with a photo
What is the actual structure of a tooth? Many mistakenly consider it a bone. However, in fact, this is a full-fledged organ of the human dental jaw with its own functions and device. If any of the bones are examined under a microscope, a number of differences can be identified that prove this statement.

The human dental system begins to form during fetal development. There are three main parts of the tooth - roots, neck and crown. When a person smiles, only the crown is visible. The clinical anatomy of the teeth in the section is presented for visual reference in the photo to the article.
Also, the tooth has a cavity and surfaces. The surfaces of the tooth and their names are clearly indicated in the diagram for the article. The internal cavity consists of the root canal and the coronal cavity - blood vessels and nerves pass through here. On the crown part, five main surfaces of the tooth are distinguished:
The occlusal surface of the tooth is a generalized name for the cutting edges of the canines and incisors and the chewing surfaces of the molars and premolars, the surface is directed towards the antagonists.
Medial approximal - the contact surface facing the neighboring unit from the side of the center of the row.
The distal approximal surface is the same as the medial. The difference of the distal tooth surface is that it faces from the center of the row of teeth.
Lingual - the surface facing the inside of the mouth, to the tongue, which explains the name of this surface of the tooth.
Vestibular - the surface of the tooth, which "looks" in the vestibule of the oral cavity, in the back teeth is also called the vestibular buccal surface, and in the front teeth - the vestibular labial surface (see also: description of the functions of the organs of the human oral cavity with a photo).

Crown
Depending on the type of tooth, the appearance, shape and size of its crown part may be different. In dentistry, anatomical and clinical crowns are distinguished:
The first is the part that is covered with a protective layer of enamel. Its dimensions remain unchanged throughout the life of the dental element.
Protruding above the gum and visible when smiling and talking is called the clinical crown. When eruption or during a recession, its size may change. Plaque accumulates on this part and caries most often develops. In most cases, the disease affects the chewing surface of the tooth.

neck of the tooth
The neck is the least protected part. Normally, it is located inside the gums. The surface of the anatomical neck of the tooth is not covered with either enamel or cement - this area corresponds to the cement-enamel border. In the anatomy of human teeth, it is the site of the transition of the crown (anatomical) to the root. The neck of the tooth is characterized by a narrowed shape.
Roots
The root is a part of the dental element located in the alveolus and performing a fixing and holding function. That is, thanks to the root, it stays in its place. It has the shape of a cone and ends with a tip. covered with cement. Depending on the type, the number of roots can vary from 1 to 3. A bifurcation is a place where a pair of roots separates. If there are three of them, then this point will be called a trifurcation.
Histological structure
The histological structure is arranged very reasonably. Due to the peculiarities of the structure of the molars, they perform their functions and signal the occurrence of pathological processes, including the development of caries, due to the multiplication of microbes in the nutrient medium of plaque. In the photo for the article, you can see the main components of the structure under a microscope. Histological structure of a human tooth:
Pulp and periodontium, the structure of the tooth root
The pulp is a soft loose tissue in the structure of the tooth. It contains a network of nerve fibers and blood vessels that make up a human tooth. The older the person, the smaller the volume of the soft part in his teeth, since over time it is replaced by deposits of secondary dentin. The main functions of the pulp include responding to stimuli, forming and nourishing dentin tissues.
The composition of the periodontium (or pericement, as it is called in some sources) includes a system of nerve fibers and blood vessels, collagen fibers. This connective tissue fills the space between the alveolus (wall) and the cementum of the root. Periodontal is designed to perform the following functions:
stimulation of metabolic processes in periodontal tissues;
transfer of masticatory pressure to the walls of the hole;
perception and depreciation of the loads arising from chewing food.

You can clearly see the structure of the root in the photo to the article. This part of the tooth is about 60-70% of its total length. Located in the gum. The anatomy of the roots can vary not only depending on their type and location, it is also influenced by genetic factors. The roots of the teeth are not continuous. Each of them has an apical opening and channels through which vessels and nerves pass.
Features of the structure of milk teeth in a child
Milk teeth in a child constitute a temporary bite. In their structure and form, they are similar to indigenous ones. They also have a coronal part, a neck and roots. However, the anatomy of temporary teeth has its own characteristic features.
Many believe that milk teeth are completely devoid of roots or have only weak thin roots. In fact, temporary roots are very similar in shape to permanent roots, but are smaller. Approximately 1.5 - 2 years before the baby tooth falls out, its root begins to dissolve, so it is difficult to detect it by the time the bite changes. The shape of a milk tooth can be seen in the figure.
There are tables that present the approximate timing of the change of bite. If the child's process is slightly different from the theoretical values, this is not a reason for panic.
Another feature of milk teeth is thin enamel and a small layer of dentin. This is primarily due to the size of temporary dental elements, as well as a short “planned” service life. The main disadvantage of this feature is that, due to the thin protective layer, children's teeth are susceptible to the influence of pathogenic microbes that provoke caries, which quickly passes into the stage of pulpitis.
And finally, a selection of interesting facts about human teeth. It is worth starting with the fact that the teeth contain almost all the calcium that can be found in the body - they get up to 99% of this substance, while the rest of the skeleton has to be content with the "miserable" remnants. Most of the calcium is concentrated in the enamel, which protects the inner layers of the tooth from the penetration of microbes.
Below is a selection of the most interesting information about teeth:
to get rid of bleeding gums, it is enough to eat two grapefruits a day, the diet will not only relieve inflammation, but also normalize metabolism and promote weight loss - however, it will not be superfluous to undergo a professional cleaning procedure to get rid of plaque;
the most dangerous sport for a smile is ice hockey;
in rare cases, a child can be born already with one or two teeth, Gaius Julius Caesar was one of these amazing babies;
the famous Greek doctor Hippocrates began to call temporary teeth in children "milk", he thought that these dental elements are formed from mother's milk;
if you pay attention to the images of the teeth of our ancestors, you can find that there were not 32, but 44;
scientists have proven that teeth are directly related to memories, and losing one of these organs for some reason, a person loses part of his memories.

Healthy and beautiful teeth are an adornment of any person. Pink gums, an even bite and a snow-white smile indicate that a person has excellent health and, in general, is considered a sign of his success. Why is so much attention paid to the teeth and why did it happen?

General concepts of teeth and their classification

Teeth are special bone formations that carry out the primary mechanical processing of food. People have long been accustomed to eat rather hard food - meat, cereals, fruits of plants. This food needs considerable effort to process, and therefore healthy teeth have always been considered an indicator that a person eats varied and well.

To begin with, what you need to know about teeth - these are the only organs in the human body that not recoverable. Both their seeming reliability and fundamentality are quickly violated by bad habits and poor care.

And if milk, primary teeth are fragile precisely because of their temporary purpose, then the molars are given to a person until the end of life. In general, the entire dentition in humans is divided into the following types:

fangs;
incisors (lateral and central, they are also called lateral and medial);
molars or large molars (this also includes the upper and lower wisdom teeth that grow in a person at a mature or young age);
premolars or small molars.

As a rule, the location of the dentition on the upper and lower jaws is recorded using the so-called dental formula. For molars and milk teeth, this formula differs only in that the molars are most often indicated using Arabic numerals, and milk teeth - in Latin.

For an average adult, the dental formula looks something like this: 87654321 | 12345678. The teeth are indicated by numbers - any healthy person must have one canine, 2 incisors, 3 molars on each side, 2 premolars on the upper and lower jaws. As a result the total number is 32 pieces.

For babies who have not yet changed temporary teeth, this formula looks different, since there can be only teeth about 20 pieces. As a rule, temporary teeth erupt by 2–3 years, and by 9–12 they are completely replaced by permanent ones. However, not all people can boast of having all 32 teeth sprouted.

Since wisdom teeth or third molars can appear in adulthood, or they can be completely in their infancy all their lives, and in this case in a person in the oral cavity will be 28 teeth. Moreover, the structure of the lower and upper jaw has certain differences.

Anatomical structure

The anatomy of a human tooth suggests that it is conditionally divided into 3 parts: root, neck and crown. The crown is called the raised part above the gum, it is covered with enamel - the strongest tissue that protects the dentary from the negative effects of acids and bacteria. There are several types of crown surfaces:

The neck is the part that is between root and crown connecting them, covered with cement and closed by the edges of the gum. The root is the part with which the tooth is attached in its hole. Taking into account the classification type, the root can be with one or more processes.

Histology

The histological structure of all teeth is exactly the same, but all of them have a different shape, taking into account the specific function performed.

Enamel. it durable fabric, which consists of 95% different salts like zinc, magnesium, copper, strontium, fluorine and iron. And 5% are substances such as carbohydrates, lipids, proteins. In addition, the enamel contains a liquid that is involved in physiological processes.

At the same time, enamel also has outer shell, which is called the cuticle, it covers the chewing surface, but over time, the cuticle tends to wear off and become thinner.

The basis of the bone tissue of the tooth is dentin is a collection of minerals surrounding the root canal and the entire dental cavity. The dentin tissue has a large number of tiny channels through which metabolic processes take place and nerve impulses are also transmitted through the channels.

Root structure: pulp and periodontium

The cavity inside the tooth is formed by the pulp - this is a loose and soft tissue, permeated through with nerve endings, as well as lymphatic and blood vessels.

The structure of the roots looks like this. The root is in a special hole - the alveolus, in the jaw bone. The root, like the crown, consists of a mineral tissue - dentin, covered on the outside with cement.

Root ends with an apex, through its opening pass blood vessels that feed the dentary. The number of roots can vary, taking into account the functional purpose of the teeth, from 1 root in the incisors, to 5 in the chewing ones.

Periodontium is connective tissue, which fills the gap between the socket of the jaw and the tooth root. The fibers of the tissue, on the one hand, are woven into the cement of the root, and on the other hand, into the tissue of the jaw bone, due to this, the tooth is firmly attached. In addition, through the periodontal tissues, the nourishing elements of the blood vessels can enter the dental tissues.

Description of the dentition

Incisor teeth. The human jaw is symmetrical and includes the same number of teeth of each type. But there are certain anatomical features of the upper and lower jaws. Let's analyze them in more detail.

The incisors are the front teeth.. A person has eight of them - 4 from the bottom and 4 from the top. The incisors are needed to bite through food, to divide it into parts. The peculiarity of the structure of the incisors is that they have a flat crown in the form of a chisel, with rather sharp edges.

On anatomical sections, there are three tubercles, which are erased throughout life. Above the jaw two central incisors- in its group, the largest of all incisors. The lateral incisors are similar in shape to the central incisors, but smaller in size.

Remarkably, the directly cutting edge of the lateral incisor also has three tubercles, and often takes on a convex shape as a result of the development of the central tubercle. The incisor root takes the form of a cone, and is flat and single. A distinctive feature of the incisor - from the side of the cavity of the tooth are three pulp apices corresponding to the tubercles of the cutting edge.

The anatomy of the upper teeth is slightly different from the structure of the lower dentition, so everything is exactly the opposite on the lower jaw. Medium incisors are smaller unlike the lateral ones, they have a shorter and thinner root than the incisors on the sides. The outer surface of the incisor is slightly convex, while the inner surface is concave.

Incisor crown, side curved to the lips and very narrow. The cutting edge has 2 corners - in the center, sharper, and inside - more blunt. They have longitudinal grooves on the root.

Chewing teeth and fangs

The fangs are used to break food into smaller pieces. The anatomy of the canines is such that there is a groove on the inside of the crown, which disproportionately divides the crown into 2 parts. The cutting edge of the fangs has one pronounced and developed tubercle, which makes the cone-shaped crown often look like the fangs of a predator.

The canine on the lower jaw is narrower in shape, the ends of the crown are concentrated in the medial tubercle. The canine root is flat, deviated inward and the longest, unlike the roots of other teeth. In man 2 canines on both jaws. Lateral incisors with fangs form an arc where the transition from incisors to chewing teeth begins in the corner.

Consider the structure of the small chewing tooth first, and after the large chewing tooth. Their main task is meticulous food processing. This function is performed by molars and premolars.

premolars

The first premolar (No. 4 in the dental formula) differs from the incisors and canines in its prismatic shape; there are convex surfaces on the crown. The surface has 2 tubercles - lingual and buccal, between them there are furrows.

The buccal tubercle is much larger than the lingual one. The root of the first premolar has flat shape, but already with a slight bifurcation into the lingual and buccal parts.

The second premolar is similar in structure to the first, but its buccal surface is much larger, and the root has a compressed anteroposterior direction and tapered shape. At the first lower premolar, the chewing surface is inclined towards the tongue.

The second premolar is larger than the first due to the fact that both tubercles are symmetrical and equally developed, and the depressions in the enamel between them look like a horseshoe. The root is the same as that of the first premolar. In a person in the dentition there are 8 premolars, four on each side (on the lower and upper jaws).

molars

In the upper jaw, the first molar is the largest. Its crown is similar to a rectangle, and the chewing surface is a diamond-shaped shape with 4 tubercles. This molar has three roots: one straight - the most powerful, and two buccal - flat, deflected in the posterior direction.

The first molars, during the closing of the jaws, rest against each other and form a "limiter"”, because of this, they undergo significant stress throughout a person’s life.

second molar has a smaller size. The roots are the same as those of the first molar. The structure completely coincides with the location of the premolars described above.

On the lower jaw, the first molar for chewing food has five tubercles. This molar two roots- front with two channels, rear - with one. In this case, the anterior root is larger than the posterior one. In the lower jaw, the second molar is similar in structure to the first. The number of molars in humans is the same as premolars.

The third molar is called wisdom tooth”, and in total a person has four of them in the dentition, two on each jaw. On the jaw from below, the third molar has many variations in the development of tubercles. As a rule, there are five of them. But, in general, in humans, the structure of the “wisdom tooth” is the same as the structure of the second molar, but the root usually resembles a very powerful and short trunk.

Baby teeth

The histological and anatomical structure of the milk tooth is similar to the structure of the molar, however, there are certain differences:

In the end, I would like to note that, of course, the layout of the teeth in the jaw, their structure, closure have an individual character for each individual person. But the dentoalveolar apparatus of each person performs vital functions throughout life, therefore, over time, the dental structure changes.

We must not forget that in dentistry, many pathological processes appear in childhood, so you need to monitor the condition of the teeth since childhood. This will help you avoid problems in the future.

Despite the apparent simplicity, teeth are quite fragile and complex system, with a multilayer structure, where each layer and element has its specific purpose, as well as certain properties. And the fact that the change of teeth takes place only once during a lifetime makes the structure of the human jaw different from the anatomy of the jaw of other representatives of the fauna.