I. Why do I need to take X-ray dental film for dental treatment? X-rays of teeth, commonly known as dental films, are one of the important tools for dentists to treat diseases. Through dental films, dentists can learn how extensive the decay is, whether the toothache is caused by inflammation of the nerve or the root or periodontal inflammation, whether the conditions for dental veneers are sufficient, the amount of bone needed for dental implants, developmental malformations, certain tumors, etc. Before treatment, it can help to detect the lesion and determine its degree and scope; during treatment, it can guide the treatment, determine the treatment scope and treatment depth; after treatment, it is easy to observe the efficacy. Second, what kinds of dental films are there? Dental films mainly include panoramic films and small dental films. Third, how much radiation is used to take dental films? According to the previous recommendation of the International Commission on Radiological Protection, the general radiation limit should not exceed 5 millisieverts (mSv) per person per year = (5000 microsieverts (μSv)). The radiation dose for a dental radiograph is about 5 mSv, for a chest radiograph is about 20 mSv, and the annual radiation dose limit for radiation workers is 50 mSv per year. If the dental film is digitalized, the radiation dose is smaller than that of the traditional film type. Fourth, how much radiation hazard is there in taking dental films? Usually a person is exposed to an annual radiation dose of about 4 mSv, which is a very small and safe dose. And about 85% of this radiation comes from nature, and only about 15% of the remaining is medical examination. Each of us lives in nature and is exposed to radiation every minute of every day. Even if you sleep with others, you are also subject to radiation from the body of others, about 0.05 microsieverts. Even if you prefer to be alone, then the annual radiation dose of potassium in your body is about 390 microsieverts. Then there is watching television, for example, which has a radiation dose of about 1 microsievert a year. You casually eat a banana, the radiation dose is about 0.1 microsieverts. Spending a day in an area with above-average natural background radiation, such as the Tibetan Plateau, the radiation dose is about 1.2 microsieverts. Based on smoking two packs of cigarettes per day, the radiation dose of radionuclides in cigarette tobacco is equivalent to one X-ray chest X-ray per day. There are also airplanes to high altitude, ubiquitous cell towers, microwave ovens at home, electric lights, and so on, including of course, we can not leave the cell phone, so there is no need to worry about a small dental film. V. Pregnant women and children, can dental films be taken? In certain dental treatment emergencies, pregnant women may have to take dental films before the baby is born. Untreated dental infections can pose a potential threat to the fetus. Since dental treatment is usually a free choice, it is generally not advisable for pregnant women to have dental x-rays taken during the first trimester of pregnancy, as the fetus is more sensitive than normal, and this can be avoided if possible. After the third trimester, if a pregnant woman must receive an X-ray, as long as it is not a high dose of X-ray radiation to the abdomen or its vicinity, the mother can not worry too much.