How teeth grow, understand the growth cycle of teeth

Teeth are developed from tooth germs, which form crowns and roots. When the crown breaks out of the gum, the root of the tooth will continue to develop, and the root of the tooth will only develop after 3 years, and then the tooth will really grow.

The growth of teeth is the eruption and growth of primary teeth, and then the primary teeth fall out after a period of time, and then fall out of permanent teeth, and the eruption of each tooth has a certain time, and the replacement of permanent teeth and baby teeth also has a certain regularity.

In the sixth week of pregnancy, the tooth germ of the baby teeth appears in the mouth of the fetus, calcification begins at about four months, and then the baby teeth do not grow out until six months after the child is born, so the mother's nutrition during pregnancy is very important; The so-called healthy baby has healthy teeth. Usually the first incisor of the lower jaw is the earliest baby tooth that erupts, about 6 to 7 months after birth, which is the first time when the whole mouth erupts in the mouth, and it is also the standard used by dentists to determine whether the baby teeth are born early or too late. After that, a new pair of baby teeth erupts about every four months.

When a child is 2 to 3 years old, all 20 baby teeth appear in the mouth. After the age of six, the permanent teeth begin to erupt and the baby teeth gradually fall out, and this condition is not fully completed until the age of twelve. This is the time it takes for baby teeth to be replaced with permanent teeth.

Generally speaking, around the age of six, a tooth will grow behind the second mapillary molar of the child's lower jaw, that is, the first molar of the permanent teeth, we call it a six-year-old tooth, this tooth is the earliest permanent tooth, and the function is also the most important. After the tooth erupts, the baby teeth are replaced by permanent teeth one by one according to the general procedure.

When the child is between 12 and 14 years old, he or she will have twenty-eight permanent teeth.

Ten. After the age of seven or eight, the large molars of the upper and lower jaws erupt, that is, the so-called wisdom teeth, which are slippery to form 32 permanent teeth, but some people have the third largest molars buried in the bone and do not erupt, and some people do not grow these four teeth at all, so it is normal for human permanent teeth to grow between 28 and 32.

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Tooth growth and bone have a certain relationship, but because the embryo** is not exactly the same, the growth of teeth and bones is not completely parallel. At birth, the baby teeth are ossified, and the baby tooth spores are hidden in the jaw bone and covered by the gums; Ossification of permanent teeth begins in the neonatal period, and the third permanent molars have ossified by 18 to 24 months. A person has two sets of teeth, primary teeth (20 in total) and permanent teeth (28 to 32) in life.

Baby teeth begin to erupt 4 to 10 months after birth, and those who do not erupt after 12 months are delayed in eruption. The eruption order of baby teeth is generally as follows: the lower jaw precedes the upper jaw, from front to back, and the baby teeth emerge at about the age of the year. The eruption time of baby teeth varies greatly among individuals, which is related to genetic, endocrine, and food traits.

eruption of the first permanent tooth around the age of 6 (first permanent molar, after the second deciduous molar, also known as 6th instar tooth); 6 At the age of 12 years, the primary teeth are replaced by the same permanent teeth one by one, in which the premolar replaces the primary molar, which is the mixed dentition stage; eruption of second permanent molars at the age of 12; The third permanent molars (wisdom teeth) erupt after the age of 18, and there are also lifelong third permanent molars that do not erupt.

Teething is a physiological phenomenon, and individual babies may have symptoms such as low-grade fever, increased saliva, salivation, restless sleep, and irritability during teething. Healthy growth of teeth is linked to nutrients such as protein, calcium, phosphorus, fluoride, vitamins A, C, and D, as well as thyroid hormones. The chewing of food is beneficial for tooth growth.

Diseases such as poor ectoderm growth, calcium or fluoride deficiency, and hypothyroidism can be seen when teeth grow abnormally.

The process of tooth development is quite long and complex, and the teeth begin to develop and grow during the fetal period before the baby is born. Around the seventh week of pregnancy, the baby teeth begin to develop, first forming the baby tooth germ, which resembles the "germ" of the tooth. By about five months of pregnancy, the fetus has basically formed the cusps of baby teeth.

By the time of seven months of pregnancy, the fetus's primary tooth crowns will form about 1 2; By the time the baby is born, almost all of the 20 baby teeth have formed crowns.

At the same time as the baby teeth grow, the permanent teeth are also quietly brewing, and the permanent tooth germ also begins to develop gradually at four or five months of pregnancy, but the calcification of the permanent teeth mostly begins gradually after birth, and does not grow out one after another until the baby is six months old. This means that when your child is born, there are already 20 baby tooth germs and 16 permanent tooth germs in the jawbone. Although you can't see the teeth in your baby's mouth when he or she croaks to the ground, this is because they are hiding under the gums (commonly known as "gums") and have not yet erupted.

It is not until about half a year of age that the first tooth comes out from under the baby's gumbed. By the time the child is two-and-a-half to three-year-old, the child's small baby teeth (20) will be ready to grow. Therefore, the health of the mother during pregnancy will directly affect the health of the child's teeth.

Some children are born with teeth in their mouths, which are called birth teeth (commonly known as "horse teeth"). Of course, this is a rare occurrence, and the vast majority of people are born toothless.

Humans have two sets of teeth. The first group is called baby teeth (baby teeth or milk teeth) and appears about 6 months after the baby is born. Children have 20 baby teeth, which are evenly distributed in two rows.

Between the ages of 9 and 12, humans will develop a permanent set of teeth called permanent teeth or permanent teeth. Permanent teeth form under the primary teeth and are pushed out of the jawbone and replaced. The new set of teeth has a total of 32 teeth, and the jaw bone has grown up accordingly.

After the age of 12, wisdom teeth, the so-called third molar, that is, the two ends of the upper and lower rows of teeth, have a total of 4 teeth, which is often referred to as wisdom teeth. Wisdom teeth erupt most of the time. The reason for not growing out may be that the jaw is not well positioned or in some cases it is not present at all, but usually one of them is missing at most.

Since the jaws of most Caucasian and yellow people are not large enough, wisdom teeth are generally extracted in order to prevent tooth decay and inflammation caused by food storage, as well as the forced outgrowth of teeth that may cause the whole set of teeth to become crooked.

It's complicated, depending on the age you ask.

In this way, the teeth are protected and the teeth are wide, and the longevity is "added" to the cracked ruler, and the yellow teeth are improved, and the gums are hot.