How many teeth a person should be just
Sometimes is the question, how many teeth in humans. This is particularly interested when there are signs of teething at the age of thirty, growing a young child or after the age get the tooth without root. How many teeth in an adult human, we will discuss in this article.
The structure of teeth and their purpose
Human teeth serve an important function tearing and shredding pieces of food. Thanks for digesting spent significantly less energy. Laying begins in utero. So, milk teeth laid, differenciate and mineralized 20 weeks of pregnancy. Therefore, it is important that the expectant mother receives a maximum of useful minerals such as calcium and phosphorus. If a woman suffers from morning sickness or she had a viral infection, the child may be anomalies of development or eruption, hyperplasia or hypoplasia.
The beginnings of permanent teeth in humans are laid in the last weeks of embryogenesis and continues through the ninth month of life. If a child in this period were ill or had a poor diet, then the chances are the manifestations of non-carious lesions.
A tooth can be divided into three anatomical parts:
- root. Thanks to him, the tooth remains in the gum. The root penetrates deeply into the jaw bone. It’s covered with cement, the inside is a channel through which pass the nerve fibers. The root is tightly fixed by the fibers of the soft tissue, but it is still somewhat movable, so as to prevent fracture when chewing. The number of roots is different;
- neck. Located in the gums. It starts in the end of the enamel;
- crown. Rises above the gums. It is completely covered with fabric strength comparable to diamond — enamel. The function of enamel to protect from mechanical and chemical damage, the dentin. Dentin the main part of the tooth that is permeated with the bone, consisting of collagen, saturated with minerals, which gives strength with low brittleness. In the heart of the bone formations located pulp. It contains nerve fibers and blood vessels.
The teeth differ in shape and have different functions. There are 5 varieties:
- the incisors. Have cutting edge, which makes it possible biting and tearing food. Isolated Central incisors and lateral. Only 8 of them have one root and canal;
- fangs. Located near the side cutters have a conical shape. Need to cracking food. In humans, they developed much smaller than that of predatory animals. 4, in one canal and one root;
- small molars or premolars. The so-called Quartet, on the surface have two bulges, which helps to chew food. There are only 4: in the upper jaw two roots and two canal, in the lower one;
- large molars or molars. Necessary for grinding the food. On the surface there are 4-5 tubercles and depressions (fissures). All posterior teeth 16, 4 on each side of the jaw. In the main on one channel and root in the top six at the three roots and canal, in the lower two roots and three channels. In the top seven to three roots and four canals, two roots at the bottom and three bands.
The norm teeth for an adult
Thus, a complete set of teeth is 32 pieces. The latest in the dentition of the «eight» are called wisdom teeth. Their beginnings in contrast to the other formed only to 12 years and erupt at age 17-25 years. But according to dentists, half of the world’s population today, they do not erupt completely due to the fact that they do not have enough space in the jaw. These bone formations to humans are the rudiments. From the point of view of evolution, the need for them has disappeared, because man is not chewing bones, most products are crushed and subjected to heat treatment.
Often wisdom teeth are impacted, that is, remain partially hidden under the bone or gums, growing out of the dentition, for example, rests on the cheek or on the seventh molar. This causes a lot of discomfort and want to remove them. In addition, even prorezalsya the tooth quite quickly deteriorates because caring for them is difficult. Dentists propose to remove rather than treat.
When and in what sequence cut first teeth
The first tooth in humans appears around six months of age. Is considered normal if the body began to erupt only a year. Sometimes the child is born with incisors. Generally, the milk teeth erupt in pairs with a small time interval. There is a certain order of eruption:
- lower, then upper Central incisors (6-8 months);
- lateral incisors (8-12 months);
- premolars (1-1,5 years);
- fangs (1.2 to 2 years);
- second, indigenous to three years.
The milk teeth differ from the permanent structure of the roots. Due to this the facial skeleton can continue to develop and grow. From where erupted milk tooth, and depends on the location of the indigenous. Therefore, milk teeth sort of fitting. Except for the structure of the roots of the baby from the adult heart are different size crowns, thick enamel and dentin volume. To three years a child’s kit is assembled, and it consists of 20 teeth. Though they differ in their structure from the «adults» of the indigenous, but still serve the baby up to six years.
Change of milk teeth
In the preschool period begins the change of milk teeth to permanent. First gaps are formed between them. This physiological process gives the molars, which are more dairy, grow and become exactly. Simultaneously with the formation of cracks begin to dissolve the roots of the milk teeth, because they are pushing the permanent tooth, thereby blocking the blood supply. As soon as the roots are resorbed, tooth becomes mobile and is easily removed from the wells. When a spot opened up, begins to grow a permanent body.
The first permanent teeth grow in four years, it is six (large molars.) Complete replacement of milk teeth occurs up to 12-13 years.
Often parents worry that the permanent incisors erupt far from each other and to the side. But at the beginning it is normal. When the process of teething will end, they will fall into place. About a malformed bite can only speak at the age of 13-14 years.
The whole replacement process takes about 6-8 years, so it’s hard enough to keep track of how many permanent teeth already erupted. Sometimes milk teeth can last much longer. This can occur due to injury or to infectious diseases, injuring the permanent tooth germ and it ceased to evolve and to provoke the loss of the milk tooth.
Exceptions to the rule
So, the normal number of teeth in human is 28-32. But there are exceptions to the rule. The number of teeth in an adult human may vary both upwards and downwards. There are children who have in utero is not formed rudiments of milk teeth. This pathology is called Edentia.
If bone formation is less than the norm, it hypodontia. It can appear because of a split or death of the embryo. Pathology, usually provoke infectious diseases such as syphilis, tuberculosis. Hypodontia may occur in the absence of a tooth or a breach of its shape and structure.
Hyperdontia a disease characterized by the excess amount of germs, and it is found in 5% of people. Such bodies need to be removed. Hyperdontia can manifest in the increasing number of canines and incisors. It is an atavism, it is believed that our ancestors had for 6 cutters. Put forward the theory of the splitting of the embryo. In 2014 there were cases removal of 80 and 232 supernumerary tooth. For diagnostic pathology required panoramic x-ray, where you can visualize all the impacted bodies.
Now you know how much should be teeth norm and what may be pathology. But whatever it was tooth, milk or root, it requires careful maintenance.