1, the biggest oral changes in school-age children is tooth replacement, abnormalities should be found in time for medical treatment The biggest change in the oral cavity of school-age children is tooth replacement. At this stage, the child’s 20 milk teeth will gradually be replaced by 28 permanent teeth. Tooth replacement is a physiological process, and the normal order is that milk teeth are loosened and lost first, and permanent teeth then erupt. If the milk teeth have not fallen, permanent teeth have erupted first, the new eruption of permanent teeth often can not enter the tooth row smoothly, resulting in misalignment of permanent teeth, this time should be consulted as soon as possible. 2, active prevention and treatment of dental trauma Participating in sports activities and games, children are best to wear rubber-soled non-slip travel shoes, sports shoes. In skateboarding, rollerblading and other high-velocity, high-risk sports, should wear helmets, dental brackets and other protective gear to reduce the risk of dental injuries. Teeth are non-renewable hard tissues. If an injury results in bleeding gums, cracked, broken, loose or displaced teeth, you should go to the hospital immediately. If the whole tooth is lost, find the tooth as soon as possible, pinch the crown area with your hand and rinse off the dirt on the surface of the tooth with cool boiled water or tap water, but never brush or scrape the root, and then put the rinsed tooth back into the socket; or you can soak the tooth in fresh, cold milk, saline, or contain it in your mouth and go to the hospital quickly. The shorter the time the tooth leaves the mouth, the greater the possibility of successful reimplantation, and it is best to be treated within 30 minutes. 3.Preventing fissure caries of “six-year-old teeth” (the first permanent molar) with fissure sealing method “six-year-old teeth” is the earliest permanent molar eruption time, and its chewing function is the most powerful, and it is also the most prone to caries, and even cause premature loss, so it is very important to protect the first permanent molar of children. Therefore, it is very important to protect children’s first permanent molars. Fissure sealing is the most effective way to prevent fissure caries of permanent molars. The principle is to use polymer material to fill the fossa of the teeth, so that the surface of the teeth becomes smooth and easy to clean, and bacteria are not easy to stay, so as to achieve the role of preventing fossa caries. It should be reminded that the fossa should be brushed properly after sealing, and if the sealant is found to fall off during regular oral examination, it should be re-sealed. 4, pay attention to the prevention and treatment of adolescent gingivitis adolescent gingivitis manifested as brushing and biting hard objects when the gums bleed, swollen gums, oral odor, etc., the cause of which is related to changes in the level of sex hormones during puberty, and more importantly, the accumulation of dental plaque. Therefore, the most effective way to prevent and treat adolescent gingivitis is to brush teeth effectively to remove plaque. After bleeding gums, you should pay more attention to brushing, you can put a little more toothpaste in the bleeding area, gently and repeatedly brush several times, and combined with the use of dental floss to thoroughly remove the plaque. When the above methods do not work, you should go to a qualified medical institution. 5, misalignment of teeth should be timely diagnosis and treatment Just erupted between the two upper front teeth gap is large, under normal circumstances with the eruption of other front teeth, the gap automatically disappear. If the gap is too large or can not be closed automatically, should go to the hospital for examination. Parents should not simply use a rubber band to “strangle” the gap. Usually around the age of 12, milk teeth are completely replaced by permanent teeth. If there are teeth misalignment and other occlusal deformities, can be corrected during this period, easy to achieve good therapeutic results. It should be reminded that children undergoing orthodontic treatment should brush their teeth after every meal to remove plaque and retained food debris, and it is recommended to choose orthodontic toothbrushes and interdental brushes to clean their teeth.