The key is to prevent caries. The measures to prevent caries are as follows: 1.Regular check-up early detection and early diagnosis and treatment. 2.The use of fluoride toothpaste contains fluoride (such as sodium fluoride), which has the effect of preventing caries. 3.Coating medicine regularly to the dental clinic, the doctor coated some medicine on the tooth surface, such as 2% sodium fluoride solution, 75% sodium fluoride paste, 8% stannous fluoride, etc., in order to prevent caries, which is a more effective method. 4.Children should develop good oral hygiene habits as early as possible, such as rinsing mouth after meals, brushing teeth in the morning and evening to keep the mouth clean. Parents should supervise the effect of children’s brushing, if they feel unsure, they can buy professional plaque stain, so that they can understand the effect of children’s brushing visually. 5, young children should develop good habits, such as not sleeping with sugar in the mouth and eating less snacks. Some information reported that whenever eating, the acidity in the mouth increases, teeth in an acidic environment for a long time easy to cause decalcification. To eat snacks, it is best to set a relatively fixed time in the day. 6, encourage children to eat more coarse food containing more fiber, such as vegetables, and less fine food, especially sucrose carbohydrates. Fine food is easy to stick to the tooth surface is not easy to remove, and rough food chewing time is longer, chewing on the tooth surface to play a mechanical cleaning effect to reduce the attachment of bacteria in the tooth surface and acid production. 7.Pregnant women take in rich nutrition during pregnancy, such as sufficient protein, calcium and phosphorus elements and vitamin D, etc., which is favorable to the development of fetal tooth embryo, so that the teeth form good structure and have the natural ability to resist caries and various dental diseases, which plays an important role in preventing caries, etc. 8.After the milk molar erupts, we should do the sulcus closure in time. When the caries of milk teeth occurs, you should go to the dental clinic in time. The doctor will do the appropriate treatment in time according to the condition. 9.If the milk tooth has extensive superficial caries, it can be properly ground out and coated with 2% sodium fluoride solution or 75% sodium fluoride glycerin paste, etc. After the cavity is formed, filling treatment should be made. If deep caries leads to pulpitis, the child should be sent to dental clinic for treatment as soon as possible if there is spontaneous or radioactive paroxysmal severe pain without localization, so as to avoid deep spread of inflammation and affect the general health of the child.