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BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
How did dentures come about? Detailed answer
Directory / Big encyclopedia. Questions for quiz and self-education Did you know? How did dentures come about? It is unlikely that you will look good if your teeth have fallen out. And besides, it very seriously interferes with eating and chewing. Therefore, a person has long guessed that a tooth that has fallen out for one reason or another can be replaced with an artificial one. Replacing lost teeth with artificial ones is called prosthetics. When real teeth fall out, a denture or bridge is put in their place. In the "bridges" the load of the "false tooth" is carried by the real teeth, which are located at the edges of the gap. In a prosthesis, an artificial tooth is attached to the gum or under it. You will surely be surprised that dentures and "bridges" were made 3000 years ago by the Etruscans, "goldsmiths". And dentures for people who lost all their teeth were made 300 years ago. The most important task that had to be solved in those distant times was how to properly install them in the mouth and what material to make the artificial teeth themselves and the base to which they are attached. Modern dentistry has solved these problems so successfully that people with dentures can eat and chew just like you and I, and an artificial tooth looks just as natural in the mouth as a real one. In ancient times, artificial teeth were made from elephant bones and tusks, even hippo teeth were used! Sometimes the entire prosthesis was cut entirely from bone and inserted into the mouth. Later, the teeth of humans and other animals (especially sheep) came into play. They were strengthened on a base of gold or ivory. At the end of the XNUMXth century, porcelain teeth came into fashion. They began to be attached to gold and platinum plates. Other porcelain products are made from the same material. It has a red structure, it is translucent and very durable. A hundred years ago, they began to select artificial teeth in accordance with the shape of the face. And today, dentures have become so similar to real teeth in color and shape that it is sometimes difficult to distinguish between them. Author: Likum A.
Who is called a mentally retarded child? A person whose mental development stops before it reaches the normal level for people is called mentally retarded. Mental retardation, or dementia, cannot be regarded as a specific disease. Rather, it is just a sign, or, as doctors say, a symptom of an illness or that not everything is in order in the body. Dementia can have different causes, and not all of them are well understood. But this phenomenon should make itself felt before the age of seventeen, when the mental development of a person basically ends. Although there is no consensus among experts on this issue, most believe that a person’s mental abilities can be measured using special tests. The results of this test of mental development are expressed in the so-called indicator of mental development, or the coefficient of giftedness, which in a normally developed average person is considered equal to 100. A person whose IQ is below 70 and who is unable to cope independently with the problems of daily life is considered demented. There are four degrees of mental retardation: minor, moderate, major and profound. The index of mental development in the severely and profoundly retarded falls below the mark of 35. Their mental abilities are not higher than those of normal five-year-old children. They cannot serve themselves and are unable to protect themselves from danger. Someone has to keep an eye on them all the time. With moderate and slight retardation, there are fewer problems. They can learn to perform simple tasks by working in special workshops. They have difficulties with reading, writing and arithmetic, but they are able to master most of the primary school subjects. Mental retardation can be caused by various reasons, among which are diseases of the mind and body, and even the difficult conditions in which the child lives. Scientists have established about two hundred factors that contribute to the development of dementia. These include birth trauma, brain tumors, blood disorders, infectious diseases caused by certain viruses, and various types of congenital dementia.
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