The most important methods to prevent tooth decay are as follows: first, brush and rinse your teeth carefully, choose your favorite brand of toothpaste, learn to use the correct brushing method, such as the Pasteur brushing method, ensure that you brush your teeth after meals every day, brush your teeth 3 times a day for 3 minutes each time, and at the same time use dental floss and gap brushes and flushers to assist in cleaning the adjacent surfaces of teeth to clean all the food residues in the gaps between teeth. Babies usually can’t brush their own teeth particularly clean, so parents need to help children brush their teeth at this time. Second, eat less sweets and carbonated drinks, these two types of food are most likely to cause decalcification and decay of teeth, and rinse the mouth in time after eating sweets and drinks. Thirdly, go to the hospital regularly to check teeth and treat cavities in time once they are found. Fourthly, children’s milk teeth should be coated with fluoride regularly in the hospital to protect the teeth from decay. Fifthly, after the permanent molars erupt, usually the first permanent molar (six-year-old teeth) erupts around 5.5-6 years old, and the second permanent molar erupts around 12 years old, during this period, you should go to the hospital to do sulcus closure to protect the permanent teeth.