Development of baby teeth. Formation and development of teeth. How teeth are formed in babies, an approximate diagram of teething. Requirements for a pregnant woman for the development of healthy teeth in the fetus

Dental development is a very important process in children, starting in the womb. The condition of future teeth depends on many factors. There are many reasons that can cause certain disturbances in the development of teeth in children and largely determine the condition of future molars.

Development and change of teeth in a child

During life, two different sets of teeth [ZB] develop. The first shift serves in childhood, and the teeth that form this generation are called milk teeth. They gradually fall out and are replaced by permanent SBs, which remain with the person for the rest of his life.

Teething is physiological and serves as an indirect indicator of the correct or impaired development of the child. As a physiological act, teething is not a painful phenomenon and cannot cause any diseases. It is in direct connection with the general health of the child - timely growth of teeth in a certain sequence indicates the normal development of his body. A discrepancy in the time of the beginning of the eruption of the central incisors by 1-2 months from the conditional period cannot be considered as the effect of any pathology.

The newborn does not have a single tooth, although in rare cases their intrauterine development is observed. In the first shift there are 20 ZB: 10 each in the upper and lower jaws. At the age of 6-7 months, the two lower middle incisors erupt first, at 7-8 months - the two opposite upper incisors. Then, at 8-9 months, two more upper incisors erupt, and during the last quarter of infancy, two lower incisors erupt. Thus, by the end of the first year of life, a healthy child should have eight teeth. By the age of two, the first primary molars and canines erupt. Second primary molars appear after another six months. Complete formation of the primary dentition is usually completed at three years of age. This set of SBs serves the child for the next 4 years, after which the milk SBs fall out and are replaced by permanent ones. The period of change of dairy SB lasts approximately from 6 to 12 years. The set of permanent STs consists of 32 - 16 upper and 16 lower. They are similar in shape to dairy ones, but are larger in size.

Like other indicators of development, the timing of teething has individual characteristics, so even healthy children may experience later or (less often) early teething. However, a significant delay in tooth growth is a symptom of a child’s existing disease, most often rickets. A delay in teething may be a consequence of rickets, an infectious disease, prolonged dysfunction of the intestines and changes in metabolism. Earlier teething - endocrine disorders. In rare cases, children have edentia - the absence of tooth buds. You can check the presence of tooth germs using an x-ray. X-ray irradiation may be unsafe for a child’s body, so this study should be performed only when necessary and as prescribed by a doctor. Today it is possible to reduce the harmful effects of X-rays if you take a picture using a radiovisiograph. Such equipment is usually available in every modernly equipped dental clinic.

At the 7th year of life, the replacement of baby teeth with permanent ones occurs, the time of eruption of which, as a rule, coincides with the resorption of the roots of baby teeth and their loss. In contrast, the formation of a permanent bite begins with the appearance of the first molars of the lower jaw and normally ends by 15-18 years. The central incisors (8-9 years), first premolars (9-10 years), canines (10-11 years), second premolars (11-12 years), second molars (12-13 years) sequentially erupt. The third molars of the lower jaw, or as they are sometimes called “wisdom” teeth, grow later, often after the age of 20-25 years.

A correctly and timely formed bite plays a big role in the normal development of the child’s body. Violation of the timing of teething (early or late), the order, as well as the absence of one or another tooth require the attention of a pediatrician and dentist, since they are evidence of pathology not only of a local, but often of a general nature (the result of diseases suffered by the mother during pregnancy, or any anomalies in the child’s health).

For various reasons, a number of deviations can occur in the structure of teeth, their location and development: the absence of a tooth germ, an incorrect position of the tooth axis (horizontal or oblique), which is why it erupts outside the arch of the dentition or remains in the thickness of the jaw bone. In addition, incorrect formation of the tooth itself - size, shape, position, color, lack of enamel coating, etc. Such changes should be analyzed by a specialist.

Features of the teething period

The eruption of baby teeth often affects the child’s well-being. In weakened children, this physiological process is accompanied by general malaise, poor sleep, restless behavior, crying, and moodiness. Sometimes the temperature rises to 37.50C, the nature of bowel movements changes, short-term rashes on the body and redness of the facial skin are possible. The child's weight gain is temporarily suspended and immune defense is reduced. To establish the true cause of the malaise, a consultation with a pediatrician is necessary. Difficult teething with increased body temperature, catarrhal symptoms, and indigestion is most often caused by an infectious disease. Therefore, the appearance of such symptoms in a baby during teething requires a mandatory medical examination and observation!

What sedatives can be used in children during teething? Do these drugs affect the teething process?

No, these drugs do not affect the teething process in any way. They have all been clinically tested and naturally have no side effects. The only limitation is children with allergies, but there is also a sedative for them - Doctor Baby. Almost all such gels contain lidocaine and inert fillers (menthol for cooling, flavoring agents and astringents).

Dentinox

Kalgel is sweet, you should not use it if you have diathesis.

Kamistad is very effective, but must be used in moderation.

Mundizal

“Solcoseryl” dental paste (available for external use, do not confuse it) – is especially effective if there are bleeding wounds or painful ulcers.

Dr. Baby - for allergies to lidocaine.

Soothing gels do not need to be used according to a specific regimen (such as antibiotics). If it hurts, you apply it, if it doesn’t hurt, don’t apply it. But don’t get too carried away, it’s better not to use it more than 3-4 times a day and more than 3 days in a row.

How to speed up teething?

There is no medication. A method that has been proven over the years is a gentle massage of the gums. Gently massage the gums with a clean finger and the child will feel better, and the tooth will erupt a little faster. Just don't press hard, don't injure yourself. Usually they give the child a cold spoon to suck on, but you can also keep the pacifier in the refrigerator for a little while and give it to the child. But don't overdo it. All this, of course, will not greatly speed up teething, but it will make life a little easier for you and your child.

Changes in the composition of saliva during teething, the appearance of bad breath.

During teething, the mucous membrane partially decomposes (lysis). Salivary enzymes play an active role in this process. As you know, the amount of saliva increases during teething. This is due specifically to the lysis process. This can actually change the viscosity, color and smell of saliva. In addition, saliva contains weak antibacterial substances that prevent infection of the wound formed during tooth eruption. Their active influence can also change the normal properties of saliva. A certain amount of blood also enters the oral cavity, and when it decomposes, a sour (metallic) odor may also arise.

For infants, the number of teeth that have erupted is one of the objective criteria by which the baby’s health status is assessed. The timing of teething and the order of their appearance can vary significantly. So, the first tooth can appear as early as 1 month or 1 year, but most often this happens at 6-8 months of life. To calculate the number of baby teeth (N), depending on age, use the formula: N = n-4, where n is the number of months of a child’s life. So, at the age of 12 months, the baby should have 8 teeth.

Possible features of teeth in children at the teething stage

Expansion of spaces between teeth. It may reflect increased jaw growth and during the transition period from baby teeth to permanent teeth is regarded as a normal condition. A wide gap between the front incisors on the maxilla is usually associated with a deep-lying maxillary frenulum. The tactics for monitoring and treating wide gaps between teeth are determined by an orthodontist.

A blackish edging on the neck of the tooth can be due to the use of soluble iron preparations or a chronic inflammatory process (precipitation of bacteria of the leptotrichium group);

Yellowish-brown staining of teeth is most often associated with the use of antibiotics by the mother in the second half of pregnancy or by the child during the period of teeth formation.

A yellowish-greenish color develops in severe disorders of bilirubin metabolism and hemolytic (destruction of red blood cells) conditions;

Reddish staining of tooth enamel is characteristic of a congenital disorder of pigment metabolism - porphyrin. This disease is called porphyria;

Malocclusions occur due to uneven growth of the jaws, due to prolonged sucking of the nipple;

Anomalies in the location of teeth occur for constitutional reasons (small jaw size), due to trauma, congenital disorders of connective tissue metabolism, and tumors of the alveolar process of the jaw.

The absence of teeth before 1 year of age is extremely rarely associated with edentia - the absence of their rudiments. You can check the presence of tooth germs using a special radiovisiography method prescribed by a pediatric dentist.

Porjadok_i_sroki_prorezyvanija_zubov.txt · Last changes: 2012/11/14 12:33 (external change)

Human teeth begin to form at the stage of intrauterine development (7-8 weeks). Part of the epithelium thickens, then a curved fold with its edges grows deep into the surrounding tissue, forming a dental plate (1). The fold itself is uneven, usually clusters of cells (dental papillae) are formed, above them something like bells protruding upward is obtained. Subsequently, enamel is formed from this epithelium itself (2), and dentin and pulp are formed from the tissues inside the bell (3). This same tissue supplies stem cells for the growing tooth. Large folds (2,3), laid down very first, become the rudiments of milk teeth. In the 5th month of pregnancy, the rudiments of permanent teeth begin to develop from smaller bell-shaped folds (4).

This process itself determines the further structure of the tooth: since the protein matrix of the enamel is formed only from the area of the ingrown epidermis, the shape of the crown and the thickness of the tooth enamel in an adult strongly depends on the characteristics of its intrauterine development at the end of the second month of pregnancy. An epidermal plate that is not deeply ingrown or receives insufficient nutrition will give rise to a small crown, or a crown with an enamel defect or with thin enamel. At this same stage, the number of teeth is formed, and the rudiments of both milk and permanent teeth are immediately formed. Normally, a person has 20 primary teeth and 28-32 permanent teeth, but there may be more or fewer teeth: this depends on the number of markers and signal sources.
The roots of the tooth are formed before eruption, and the final shape is taken 6-8 months after it (sometimes later).

Sometimes third molars do not grow at all, sometimes they grow inside the jaw, causing problems.

After the eruption of permanent molars, dental plasticity disappears, and new teeth can no longer appear. However, if “extra” rudiments remain in the jaw, they can sometimes be activated. The shape and arrangement of teeth are unique to each person. According to some studies, early human ancestors had 44 teeth, so sometimes atavisms occur regarding the increase in the dentition: either additional teeth in the main arches, or additional teeth on the palate.

Important! The formation of teeth depends on the characteristics of pregnancy. Maternal malnutrition, vitamin deficiencies (especially lack of vitamin D) or the use of antibiotics can lead to dental hypoplasia in the newborn, and both milk and permanent teeth can be damaged.

Dental formulas

In humans, different teeth have different functions, and there are four types of shape. To describe the location of teeth, there are so-called dental formulas. The human dental formula includes 32 teeth.

In a simple version of dental formulas, they simply indicate the tooth number (No. 1 central incisor), in the second case they add a number that indicates which jaw and side the tooth is located on.

The dental formula for primary occlusion is written in Roman numerals or designated as numbers 5-8.

Anatomical structure of the tooth

In a tooth, there is a crown (protrudes above the gum, covered with enamel), a root (located in the jaw socket, covered with cement) and a neck - the place where the enamel ends and cement begins; such a neck is called “anatomical”. Normally, it should be slightly below the level of the gum. In addition, a “clinical neck” is distinguished, this is the level of the dental-gingival groove. The neck looks like a narrowed part of the tooth; above and below it it usually widens.

Normally, the clinical neck is higher than the anatomical one, and the gum border runs along the enamel. However, with age, the gums atrophy and the enamel is destroyed. At certain times, it may happen that the clinical and anatomical necks coincide. In old age, when the gums descend lower and the enamel becomes thinner, wears out and disappears (near the neck it is thinner and disappears earlier), a gap again appears between these conventional boundaries, but now the level of the clinical neck will pass along the exposed dentin of the tooth.

The crown of the incisors is chisel-shaped, slightly curved, with three cutting cusps; in fangs - flattened-conical; in premolars it is prismatic or cubic, with rounded sides, with 2 chewing cusps; molars (molars) are rectangular or cubic in shape with 3-5 chewing cusps.

The tubercles are separated by grooves - fissures. Incisors, canines and second premolars have one root, first premolars have a double root, and molars have a triple root. However, sometimes molars can have 4-5 roots, and the roots and canals in them can be curved in the most strange way. That is why tooth depulpation and canal filling are always done under X-ray control: the dentist must make sure that he has found and filled all the canals.

The tooth is secured in the alveolar socket using strong collagen strands. The cementum covering the root is made of collagen impregnated with mineral salts, and the periodontium is attached to it. The tooth is nourished and innervated by the arteries, veins and processes of the trigeminal nerve entering the opening of the root apex.

The length of the root is usually twice the length of the crown.

Histological structure of the tooth

The tooth consists of three types of calcified tissue: enamel, dentin, cement. Enamel is the strongest, dentin is 5-10 times weaker than it, but 5-10 times stronger than ordinary bone tissue. Both dentin and enamel are a protein mesh-fibrous matrix impregnated with calcium salts, although dentin in structure is between enamel and dense bone tissue. If crystals of mineral salts (apatites) are lost, the strength of the tooth can be restored, since salt crystals, under favorable conditions, will again be deposited on the protein framework; however, if part of the protein matrix of the enamel is lost (for example, by chipping, drilling or grinding), this loss is irreplaceable for the tooth.

The thickness of the enamel on the lateral surfaces of the crown is 1-1.3 mm, on the cutting edge and chewing cusps up to 3.5 mm. The tooth erupts with non-mineralized enamel, at which time it is covered with a cuticle. Over time, it wears out and is replaced by the pellicle, and further mineralization of the pellicle and enamel occurs in the oral cavity due to the salts contained in saliva and dental-gingival fluid.

There are no cells inside dentin; it can partially become compacted and loosened; a protein matrix can grow in it, but only in a chamber limited by the inner surface of the enamel. Nevertheless, age-related demineralization predominates in humans. Dentin consists of thin calcified tubes running radially from the enamel to the pulp. When foreign substances or liquid enter these tubes, the increased internal pressure is transferred to the pulp, causing pain (the greater the pressure inside the dentinal tube).

Pulp is loose connective tissue. It is penetrated by nerves, lymphatic and blood vessels and fills the pulp chamber of the crown and root, and the shape of the chamber can be any. The larger the pulp relative to the overall size of the tooth, the weaker and more sensitive it is to temperatures and chemicals.
Functions of the pulp:

transmits sensory information to the brain;
nourishes living tooth tissues;
participates in the processes of mineralization and demineralization;
its cells synthesize proteins that are integrated into the protein matrix of the tooth.

The structure of baby teeth

A child is born with practically formed primordia of baby teeth. They begin to erupt already at 3-4 months of life and already at this time require care. By the time teeth erupt, the roots have not yet been fully formed, since the root grows for quite a long time. The rudiments of permanent teeth also continue to develop in the jaw, their crowns grow, but the roots will begin to form only by the time the teeth change.

In baby teeth, the tops of the roots are bent to the buccal side, and between their roots there are the rudiments of permanent teeth.

Milk teeth have a weaker layer of dentin and less mineralized enamel, their roots are shorter and thicker than those of permanent teeth of the same name. The cutting edge of the incisors usually has slightly pronounced tubercles, and the chewing tubercles are also insignificant. A large volume of pulp and a thin layer of dentin make such teeth more sensitive to sour, sweet, and hot foods. Since they are less mineralized, they are more susceptible to caries and pulpitis, and local anesthetics during treatment inhibit the production of stem cells and dentin growth in the rudiments of permanent teeth.

Important: caries that begins in baby teeth is easily transmitted to the permanent ones that replace them, since the bacteria that cause it continue to develop in the oral cavity. A baby usually gets these bacteria from the mother if she feeds him with the same spoon she eats with, or licks a fallen pacifier (instead of washing it).

Replacing teeth with permanent ones

By the time the teeth change and the active growth of the branches of the jaw begins, the child has 20 teeth. At this time, there are 2 molars on each side, but no premolars. It is the premolars that will take up the free space that appears in the branches growing in length. If the jaw does not grow quickly enough, a defect in the dentition may appear.

When changing teeth, the growing germ of a permanent tooth compresses the roots of the milk teeth, pinching the blood vessels that feed them. Gradually, the roots of baby teeth, lacking nutrition, begin to collapse and completely dissolve, so that only the neck of the tooth and the crown remain. However, the rudiments of permanent ones may also suffer. Sometimes they are involved in the process and are completely destroyed, sometimes enamel defects occur, since its protein-collagen matrix, formed from the epithelium, can easily be damaged at this stage. Hypoplasia (underdevelopment) of the tooth and the eruption of teeth with damaged enamel are very common in recent years.

Anomalies of teeth and dentition

Anomalies of tooth structure

too large (more than five) number of roots;
root underdevelopment;
uncharacteristic shape (subulate, hook-shaped, conical, flat crowns);
underdeveloped, deformed crown;
thin enamel;
increased abrasion of enamel;
absence of all or part of the enamel.

Anomalies of changing teeth

the root may not resolve in time;
the tip of the root can pierce the bone, causing an ulcer in the gum;
the root is completely exposed, as all the tissue (both bone and gums) above it is destroyed;
the permanent tooth began to grow before the baby tooth fell out;
an additional row of permanent teeth or teeth in the roof of the mouth is formed;
There is not enough space for normal tooth growth.

Anomalies of the dentition

malocclusion;
anomalies in the location of teeth in the dentition.

In all cases of anomalies with root resorption, baby teeth must be removed. If teeth grow in two or three rows or are crooked, extraction of baby teeth may also be indicated. At the same time, removing a tooth too early (for example, due to caries) can cause permanent teeth to start growing earlier, or cause the growth of additional teeth (usually small, conical ones). Additional teeth corresponding in shape to molars are formed less frequently.

Important! 5-7 years is the second critical age for dental health. It is during this period that permanent bite problems and dental defects arise, so changing teeth should be taken very seriously and not neglecting visits to the pediatric dentist.

Video - The structure of the tooth. Types and functions of teeth

Video - Anatomy of teeth

By the time of birth, all 20 baby teeth are already present in the baby’s jaw bones! And the very first signs of their formation can be noticed in the sixth week of pregnancy, when a single dental plate at the base of the jaws forms separate tooth embryos. Of course, at this time they still do not look like teeth at all - for now they are just kidney-shaped tubercles on the jaw plate. Gradually their shape will change, resembling first the cap of a miniature mushroom, and then a bell.

But it’s not just a matter of changing shape, because the main thing during this period is the never-ending process of mineralization, or accumulation of “building material” for the future tooth. Dental cement, enamel, dentin - all this is gradually deposited in the embryos, and the more calcium there is in the body, the harder these growths are on the jaw plate. But the most amazing thing is yet to come: it turns out that in the tenth week of intrauterine development, the rudiments of permanent teeth begin to form, and in the ninth month of pregnancy, the mineralization of some of them will begin.

So, a person has not yet been born, and his teeth are already in danger, and the first potential trouble is the possible underdevelopment of the tooth and its tissues: hypoplasia caused by impaired metabolic processes in the tooth germs. This pathology leads to thinning of the enamel layer and, alas, does not develop back. The cause of hypoplasia may be rubella or toxoplasmosis suffered by the mother during pregnancy. It is also observed in babies who have suffered from birth trauma, who have had jaundice, due to incompatibility of blood with the mother's blood according to the Rh factor, or in premature babies.

By the way, did you know that severe toxicosis in pregnant women leads to the removal of large amounts of salts from the woman’s body? Svetlana Kovalenko, dentist-therapist of the Moscow network of family dental clinics of the Alena company, claims that toxicosis in the second half of pregnancy can cause the unborn baby to be predisposed to caries, and abnormalities in the shape and location of teeth occur in such children twice as often as usual.

How to protect your future baby from dental troubles? First of all, pregnancy must be planned, and this means undergoing a full examination, treating all detected infectious diseases, correcting hormonal imbalances and be sure to check that the expectant mother has a rubella vaccination. You should not neglect regular visits to the gynecologist, who will help optimally solve the problem of toxicosis. In addition, it is imperative to find a competent dentist who will monitor the condition of a pregnant woman’s teeth.

The common belief that dental treatment during pregnancy is unnecessary and even dangerous is also one of the common misconceptions. In the oral cavity of any person there are about 50 million bacteria that feed mainly on carbohydrates, and during pregnancy, as a rule, the consumption of carbohydrates increases. If a woman is susceptible to toxicosis, then the acidity level of saliva will inevitably increase. Excess carbohydrates, acidic environment - why not a paradise for microflora? In such conditions, caries occurs at lightning speed, as soon as the tooth enamel is slightly damaged. And a tooth affected by caries is already a haven for a variety of microorganisms, including pathogenic ones, which can cause very unpleasant diseases not only in the mother, but also in the child.

However, caries in an expectant mother is also a signal: there is not enough calcium for two! To “help” the process of mineralization of teeth, first of all, you need the right combination of phosphorus, fluoride, calcium salts, other microelements and vitamins in the diet. Lyudmila Panova, head of Children's Dental Clinic LLC, Chelyabinsk, knows very well the mistakes made by expectant mothers - excessive consumption of carbohydrates and insufficient intake of vitamins and mineral salts. Therefore, as an experienced doctor, she recommends not to neglect simple and well-known advice: fish and seafood, seaweed, vegetables, fruits, dairy and fermented milk products, and hard cheeses must be included in a pregnant woman’s diet.

Such nutrition is very important for the teeth of the unborn child, and here's why. For proper growth and development of a strong skeleton and teeth, the future baby simply needs vitamin C, which means that it is necessary to eat citrus fruits, black currants, red and green peppers, tomatoes, rose hips and spinach. Normalizes metabolism, participates in the growth process and is extremely useful for the formation of teeth, and also for the skin, hair and nails, vitamin A, which is so rich in lettuce leaves and green parts of plants, cabbage, liver and kidneys, sea fish, egg yolk, butter , cream and fermented milk products. And vitamin E, which is contained in vegetable oils, is involved in the processes of absorption and assimilation of vitamin A.

During this period, a woman’s body also needs an increased amount of minerals, especially calcium and phosphorus, the daily need for which almost doubles. Phosphorus comes with a wide variety of products of plant and animal origin, but milk takes on very special significance as the main source of calcium for the expectant mother and for the growing child’s body.

What should be excluded from the diet so as not to spoil the smile of the unborn baby? You already know the dangers of excess carbohydrates - which means you should forget sweets for a while, especially cakes, chocolate and pies, delicious buns and spaghetti. In general, nothing new or unexpected. The main thing is that now you not only know what to do, but also, I hope, you understand why all these familiar tips are actually so important.

All new parents look forward to the eruption of their children's first teeth. But if they are not erupted according to the established standards by doctors, then adults begin to sound the alarm and worry about the babies. These concerns are quite logical, since timely teething is a sign of normal child development.

These experiences can also occur when replacing baby teeth with molars. Against this background, many questions arise: what is the time frame for the eruption of the first teeth and their replacement with molars? What teeth cut in children and at what time? Until what age do the main teeth emerge? In what order do they appear? How many should a child have before one year of age?

Symptoms and timing of teething in children

The first symptoms of teething are increased salivation, which is necessary to disinfect the oral cavity, slight swelling of the gums, and the child’s fingers and toys are always in the mouth.

Many parents indicate the appearance of high body temperature, chills and loose stools, however, these are precisely the signs Teething should not be defined specifically, since this process cannot cause such symptoms. Most likely this is an infectious disease that can easily affect a child due to weak immunity during teething.

In what order does cutting occur?

Quite often, young mothers are interested in what is the most correct order of teething in babies under one year of age. No doctor can tell the exact time of eruption, since everything happens individually for any baby. But there are still two basic rules that determine the order of teething:

"Lower Revolution". The natural system of teething in babies up to one year old implies that the lower teeth erupt first in any case, and only then the teeth of the same name appear on top. Naturally, this rule has an exception regarding the eruption of the lateral incisors (the upper ones grow first, then the lower ones);
Pairing. Teeth of the same name usually erupt almost simultaneously. If the left upper incisor sprouts, then very soon we should expect the sprouting of its right fellow. In some cases, babies may experience several pairs of teething at the same time.

Even despite the eruption time established by doctors, adults are most often based on the practical time of their germination:

Lateral incisors;
Upper and middle lower incisors;
Fangs;
First molars;
Second molars.

Some babies may begin to erupt upper. Sometimes this is a sign of rickets, but, as a rule, this is an individual feature of the child’s growth and development.

There may also be cases when there are already several teeth on top, and even no symptoms of early germination are yet to appear below. You should not worry too much in this case, if during the examination the pediatrician did not identify any violations, then the child will certainly acquire missing teeth in the near future. It’s just that this process will take a little more time and, most likely, you will need to increase the amount of foods with calcium consumed (milk, sour cream, etc.). It is necessary to remember that the drawn up diagram and growth table is only an approximate and not an exact eruption rate.

Growth time

Most often, a newly born child does not have teeth, but sometimes there may be cases when babies begin teething in the womb and are born with several teeth. As a rule, the first teeth in babies under one year of age grow in pairs with an interval of several months. The middle lower incisors usually grow first, this happens at the age of 7-8 months, then the middle upper incisors appear.

At about one year of age, the upper lateral incisors appear, and after a short time, the lower ones appear. At about one and a half years, the first molars appear, then the fangs, and when the baby reaches the age of about two years, the second molars appear.

At this stage, the formation of the primary occlusion is completed; children have only 20 primary teeth. The replacement of primary teeth with molars most often begins at the age of approximately 5–8 years.

Growth is not according to the rules

Growth retardation can be explained from a genetic point of view or the time of birth of the child. For example, babies born in winter acquire baby teeth at a fairly early age. But if at the age of one year they still have not sprouted, then You still need to play it safe and consult a dentist, since such a delay may indicate a problem with metabolic processes or be a symptom of the development of rickets. But, when baby teeth are the only drawback of a happy and healthy child, then, probably, adults simply cause unnecessary panic and quickly want to see the appearance of their baby’s first teeth.

It is also very important immediately after their appearance to begin timely care for them and accustom your baby to constant cleaning. These activities will significantly increase the chances of keeping them healthy and beautiful.

Regarding the order or pattern of growth sequence, in this case, too, everything takes place on an exclusively individual basis and the sequence of eruption may differ significantly from that generally accepted by doctors. Many dentists are confident that all aspects of development are directly influenced by the mother’s lifestyle, her illness, pregnancy and childbirth itself.

But still, when a child’s teething is completely out of place, there is no need to worry too much and escalate this situation. No one has yet made a drug that would make teeth erupt in a clear order, and when they fully grow, it will absolutely not matter in which order they appeared.

What affects the growth of molars?

The timing of the change between baby teeth and molars can be influenced by a number of factors:

Disruptions in the endocrine system;
Gender of the child;
Form of feeding and its duration;
Negative aspects of pregnancy (for example, toxicosis);
Genotype of the child;
Past infectious diseases;
Violation of metabolic processes.

It is necessary to ensure that the time of change in the molars, which are indicated in the table or calendar, coincides with the schedule for the loss of all milk teeth. It often happens that milk falls out much earlier than the required time. This can occur as a result of mechanical deformation of bone tissue, due to malocclusion or excessive pressure from the molars.

The rapid loss of baby teeth is dangerous because those nearby begin to shift, thus filling the resulting void. As a result, by the time when the time comes for the eruption of the root, there simply won’t be enough space for it and, most likely, it will be crooked.

In case of untimely loss, you need to have your child examined by an orthodontist; if necessary, he will install plates to prevent the dentition from shifting.

In the case when baby teeth do not want to fall out on their own at the right time, when the molars are already obliged to replace them, this is fraught with the development of malocclusion. You should definitely visit a doctor to take the required measures. It is very important that adults pay attention to the age at which the child’s teeth appeared and how they are located in the dentition. Since malocclusion can affect not only aesthetics, but also, in general, has a significant impact on the baby’s health.

Sequence of germination of molars

The eruption of molars in children has a special order, which makes it possible to correctly form a bite. When should they erupt, and what is their order? For better understanding, molars are numbered starting from the medial incisor.

According to the eruption pattern, the first molars or lower sixes begin to appear first. The approximate age of the baby at teething is 5–8 years. It should be noted that these teeth do not replace milk teeth, but are immediately molars. The place for their germination is provided in advance due to the growth of the jaw itself. Then the lateral middle incisors grow, followed by the first premolars, upper sixes, second premolars and canines. Full formation of molars is completed by adulthood.

Teething Features:

Brown-yellow enamel color most often associated with the use of antibiotics by the mother in the 2nd–3rd trimester of pregnancy, or the use of them by the baby during teething;
Incorrect row formation occurs for a number of reasons: genetic predisposition (very small jaw), congenital anomaly of metabolic processes in connective tissue, injury;
Increasing spaces between teeth. This feature indicates the active development of the jaws and during the transition of temporary teeth to permanent teeth is regarded as a normal condition. An enlarged gap (usually between the middle upper front teeth) appears due to the deep location of the frenulum in the upper jaw. This defect is corrected by an orthodontist;
Formation of malocclusion happens due to prolonged sucking of pacifiers or due to abnormal development of the jaws;
Gray edging around the neck area most often appears when taking soluble drugs containing iron or with severe inflammation;
Very rarely, teeth that have not appeared by one year are symptoms of edentia.- lack of rudiments. This diagnosis can only be determined using radiovisiography.

How to take care of your teeth?

It is necessary to begin oral hygiene during the introduction of complementary foods. Up to one year, this can be done using a soft toothbrush or a cloth soaked in warm water.

As your child approaches one year of age, you need to brush your child’s teeth at night without toothpaste with a special brush. It must be changed at least twice a month.

You can start using special fluoride-free children's toothpastes from the age of two years.

Instill in your child a sense of the need for periodic dental examinations for preventive purposes at least once every 6 months. The first trip to the doctor should be carried out when the first teeth erupt, at the age of approximately six months.

Get your child used to brushing their teeth twice a day, especially at night. In order to prevent the occurrence of caries, to which baby teeth are so susceptible, there is no need to abuse excessive consumption of sweets and foods with a lot of sugar.

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Posted on http://www.allbest.ru/

1. Development and change of teeth in a child

In the first shift there are 20 ZB: 10 each in the upper and lower jaws. At the age of 6-7 months, the two lower middle incisors erupt first, at 7-8 months - the two opposite upper incisors. Then, at 8-9 months, two more upper incisors erupt, and during the last quarter of infancy, two lower incisors erupt. Thus, by the end of the first year of life, a healthy child should have eight teeth. By the age of two, the first primary molars and canines erupt. Second primary molars appear after another six months. Complete formation of the primary dentition is usually completed at three years of age. This set of SBs serves the child for the next 4 years, after which the milk SBs fall out and are replaced by permanent ones.

Like other indicators of development, the timing of teething has individual characteristics, so even healthy children may experience later or (less often) early teething. However, a significant delay in tooth growth is a symptom of a child’s existing disease, most often rickets. In rare cases, children have edentia - the absence of tooth buds. You can check the presence of tooth germs using an x-ray. X-ray irradiation may be unsafe for a child’s body, so this study should be performed only when necessary and as prescribed by a doctor. Today it is possible to reduce the harmful effects of X-rays if you take a picture using a radiovisiograph. Such equipment is usually available in every modernly equipped dental clinic.

The period of change of dairy SB lasts approximately from 6 to 12 years. The set of permanent STs consists of 32 - 16 upper and 16 lower. They are similar in shape to dairy ones, but are larger in size. Two germ layers are involved in the formation of the ZB. Enamel develops from ectoderm, dentin, cementum and pulp - from mesenchyme.

2. The development of primary teeth includes several periods

Laying and formation of dental buds (early stage of development) - beginning 6-7 weeks of intrauterine development (Fig. 1).

Rice. 1 Formation of the baby tooth germ. 1 - epithelium of the oral cavity, 2 - dental plate, 3 - enamel organ, 4 - dental papilla

It begins with the immersion of the epithelium of the oral cavity into the underlying mesenchyme in the form of a dense cord (dental plate). Small epithelial protrusions called tooth germs appear on the dental plate, from which (10 below and 10 above) the milk teeth will develop. As the dental plate grows, each tooth germ increases in size, penetrates deeper into the mesenchyme and takes the shape of an inverted cup. This structure forms the enamel organ, and the underlying mesenchyme filling the cup cavity is called the dental papilla.

Differentiation of tooth germs - 3 months of intrauterine development.

The enamel organ increases in size, changes shape and gradually separates from the dental plate. Cells of the tooth germ actively proliferate and differentiate into internal, external and intermediate. The inner epithelium consists of tall prismatic cells that form enamel, hence their name - enameloblasti. The outer epithelium becomes flattened during the growth of the enamel organ; during the eruption of the gum, it merges with the gingival epithelium and is subsequently destroyed. The intermediate enamel epithelium acquires a stellate shape due to the accumulation of fluid between the cells and forms the pulp of the enamel organ; subsequently, the pulp takes part in the formation of the cuticle (thin and dense shell) of the enamel. The mesenchyme surrounding the dental anlage and the dental papilla becomes denser and forms a dental sac. By the beginning of 5 months, the enamel organ loses its direct connection with the epithelium of the oral cavity, although the remains of the dental plate can persist for a long time (sometimes cysts develop from them). Shortly before this, the cells of the dental plate form the second epithelial primordium, from which the permanent ZB will develop.

Histogenesis of dental tissues. It begins at the end of 4 months, when the most important tissues are formed: dentin, enamel and pulp (Fig. 2). Cementum is formed only 4-5 months after birth during the development of roots. Thus, during intrauterine development, only the crowns of the mammary glands develop.

Rice. 2 Histogenesis of dental tissues: 1 - dentin, 2 - odontoblasts, 3 - dental pulp, 4 - anameloblasts, 5 enamel

The source of dentin development are odontoblasts (dentinoblasts) - surface cells of the pulp, derivatives of mesenchyme. The apex of dentinoblasts has processes that secrete organic substances of a fibrillar structure - the dentin matrix - predentin. From the end of 5 months, calcium and phosphorus salts are deposited in the predentin, and the final dentin is formed.

The source of enamel formation is the internal cells of the enamel (dental) organ - enameloblasts. The processes of enameloblasts secrete the organic basis of the enamel - enamel prisms, which then calcify. The formation of dentin and enamel differs from osteogenesis in that the cells are not embedded in the intercellular substance, but move away: enameloblasts - outward, odontoblasts - inward.

During the deposition of enamel and dentin, the shape of the future dental crown is determined. Immature anameloblasts multiply and migrate into the underlying mesenchyme, forming a tube-like structure - the epithelial root sheath. It stimulates odontoblast differentiation and root dentin formation. On the outer surface of the dentin, cementoblasts appear from the mesenchyme of the dental sac shortly before the eruption of the dental plaque. They secrete collagen fibers and intercellular substance, forming cementum. The dental ligament (periodontium) is formed from the outer layer of the connective tissue dental sac.

Due to the growth and development of the root, the crown is pushed upward through the mucous membrane (Fig. 3). Root development is the most important factor in the eruption of the seal. The second factor is the growth of the pulp, leading to an increase in pressure inside the tooth germ and pushing it out due to the “reactive” force through the canals of the tooth germ. In addition, at the bottom of the dental alveoli, additional deposition of bone tissue occurs in layers. The combination of these mechanisms leads to teething.

Rice. 3 Scheme of eruption of a permanent tooth replacing a milk tooth. 1 - enamel, 2 - dentin, 3 - pulp, 4 - osteoclasts

The formation of permanent teeth occurs at the beginning of 5 months of intrauterine development. The rudiment of the permanent ZB is located behind the rudiment of the milky one. When the milk teeth erupt in the rudiments of the permanent teeth, enamel and dentin are formed. During the replacement process, the growth of the permanent tooth and the pressure of its enamel on the root of the milk tooth leads to the resorption of softer tissue by osteoclasts - the dentin of the milk tooth. The latter is pushed out and replaced by a permanent one.

3. Assessment of dental development. "Dental age"

As mentioned above, the formation of teeth begins at the end of the second, and their calcification begins from 5-7 months of intrauterine life (mainly milk teeth). Shortly before birth, calcification begins in the buds of permanent teeth, which will be the first to erupt in the future. This process is finally completed by the age of 18-25.

Since the timing and sequence of formation of primary and permanent dentition in children are quite definite (Table 2.3), they are widely used in determining “dental age,” which is established by counting the number of teeth that have erupted and matching it with standard age norms.

Milk teeth erupt from 6 months to 2-2.5 years and at this period of postnatal ontogenesis can serve as an indicator of physiological maturity.

Table 1 Time of eruption and loss of primary teeth (Losch P.K., cited from: BermanR.E., 1991)

Table 2 Time of eruption of permanent teeth (Losch P.K., cited from: BermanR.E., 1991)

There are two periods in primary dentition. The first lasts from the beginning of its formation to 3-3.5 years. During this period, the teeth are closely spaced without gaps between them, tooth wear is invisible, the bite is orthognathic due to insufficient growth and pulling forward of the lower jaw. The second period (from 3.5 to 6 years) is characterized by the appearance of physiological gaps between the teeth (diastema or trema), significant wear of the teeth and the transition of the bite from orthognathic to straight.

The change of primary teeth to permanent ones (the period of mixed dentition) characterizes biological age in the range from 6 to 13 years. During this period, a correlation between dental age and skeletal development and the level of puberty was revealed. Sex differences in dental maturity reflect the overall morphological status of the organism. In girls, a change from the primary dentition to a permanent one is noted earlier, which goes in parallel with an earlier acceleration of growth and puberty (Tonner D., 1962).

As already mentioned, the first of the permanent teeth to erupt are the molars, which stabilize the dental arch and play a large role in the final formation of the jaw and correct bite. Caries or other defects in these teeth deserve special attention; they should not be removed unless absolutely necessary. Then the sequence of eruption of permanent teeth is approximately the same as for the eruption of milk teeth. After the replacement of primary teeth with permanent teeth at about 12 years of age, second molars appear. Third molars (wisdom teeth) erupt at the age of 17-22 years, depending on individual development, third molars may not erupt at all or may take a longer period to erupt. To make an approximate judgment about the proper number of baby teeth in a child 6-24 months of age, you can use the formula:

where n is the number of life.

To make an approximate judgment about the proper number of permanent teeth in children over 5 years of age, use the formula:

where n is the child’s age in years.

Delayed teething is characteristic of gopothyroidism (delayed eruption of both primary and permanent teeth), disturbance of phosphorus-calcium metabolism, severe nutritional disorders (malnutrition, impaired digestion and absorption), chronic infections. This often manifests itself as a constitutional family feature.

Rice. 8 The sequence of eruption of baby teeth in an infant (schematic representation): a - lower central incisors (appear at approximately 6-7 months), b - upper central incisors (appear at 7-8 months), c - upper lateral incisors (appear at 8-10 months), d - lower lateral incisors (appear at 10-12 months)

Unpleasant pathological changes in the oral cavity will allow you to avoid visits to the dentist that are so unloved by all of us.

4. Structural features of baby teeth

In their structure and structure, baby teeth are very different from permanent teeth. This affects the course of pathological processes in them and the method of their treatment.

Crowns of baby teeth

The crowns of primary teeth are significantly smaller in size compared to the crowns of permanent teeth. However, the shape of the crowns of primary teeth is generally similar to the shape of the crowns of permanent teeth.

Enamel and dentin of baby teeth

The enamel and dentin of primary teeth are thin: approximately 0.3-1 mm is the thickness of enamel and 0.5-1.5 mm of dentin.

Hard tissues of primary teeth

The hard tissues of primary teeth have a low degree of mineralization, which contributes to the rapid occurrence and progression of caries.

Pulp of primary teeth

Primary teeth have a large volume of pulp. The root canals and apical foramina are wide and short, making it very easy for microorganisms and toxins to penetrate the pulp of a baby tooth.

Incisors of baby teeth

The incisors of baby teeth are more convex than permanent ones. The roots of the central incisors of the upper jaw are expanded, and their apices are curved towards the labial side.

These and some other structural features of primary teeth determine the fact that during the period of primary occlusion, up to 80% of all pathologies develop: root cysts, periostitis, osteomyelitis, pulpitis, periodontitis. That is why it is necessary to carefully monitor the condition of the child’s baby teeth and carry out timely sanitation: treatment of caries, removal of dental plaque. During this period, it is extremely important that the child receives all the necessary macro- and microelements from food.

In addition, in early childhood (1-3 years), the immunity factors received from the mother at birth begin to be lost. There is a danger of diseases of the oral mucosa (bacterial and viral stomatitis). In childhood (4-12 years), the structure and functional characteristics of the mucous membrane lead to the likelihood of a chronic, protracted course of diseases of the oral mucosa.

milk tooth enamel

5. Difference between baby teeth and permanent teeth

Unlike permanent teeth, the “service life” of primary teeth is much shorter. Resorption of tooth roots begins 2 - 3 years after their eruption in the oral cavity and continues until they fall out.

Contrary to popular belief, baby teeth, just like permanent teeth, have roots and a nerve (pulp). The roots hold the tooth in the bone. Under the milk tooth is the germ of a permanent tooth. As the permanent tooth erupts, it stimulates the resorption of the roots of the baby tooth, and by the time the baby tooth falls out, only the crown remains.

Since baby teeth (like permanent teeth) have a nerve (pulp), they can hurt if an infection from a carious cavity enters the tooth cavity, causing the development of pulpitis (inflammation of the nerve of the tooth).

Milk teeth differ significantly from permanent teeth in their size and structure.

Primary teeth are smaller than permanent teeth and have less massive roots;

Baby teeth have a more complex anatomical structure of root canals, which leads to a more labor-intensive treatment process than in permanent teeth;

The hard tissues of primary teeth are less mineralized and less resistant to abrasion and the development of caries.

the hard tissues of baby teeth are much thinner than those of permanent teeth: the inflammatory process quickly reaches the nerve of the tooth;

Why are baby teeth needed?

Milk teeth are involved in the development of functions in the child such as chewing and pronunciation of sounds. Without them, chewing hard food would be impossible. The aesthetic component plays an important role.

Also, baby teeth hold space in the dentition for permanent teeth. The eruption of primary teeth stimulates the primary growth of the jaws. The second wave of jaw growth begins during the period of replacement of baby teeth with permanent ones. Early removal of primary chewing teeth leads to the displacement of neighboring teeth into the area of the missing one and the formation of crowding of teeth in the future!

Tooth development.

The formation of the rudiments of baby teeth in the fetus begins at 4–5 months of intrauterine development. That is why the mother’s illnesses during this period lead to disruption of various stages of dental development, for example, a violation of the mineralization of the tooth occurs. As a result, the enamel can become weak and brittle. Taking certain medications during this period can also affect the development of teeth. For example, if the mother was treated with tetracycline antibiotics, the child’s teeth will be dark yellow or even brown (so-called tetracycline teeth).

Enamel mineralization begins in the prenatal period and continues for 6 months after birth. Mineralization of the crown part of the teeth has time to take place in utero, while mineralization of the cervical region of the incisors, canines and molars continues after birth, in completely new and not always favorable conditions. The mineralization process can be negatively affected by the nature and diet, social living conditions and various diseases of the child (acute respiratory infections, intestinal infections and functional diseases). That is why the cervical area is the most vulnerable and typical place for the occurrence of “bottle” caries of primary teeth.

Posted on Allbest.ru

...