Babies usually start teething at 4 to 8 months of age, but the details vary depending on the individual development of the baby. Babies generally start to erupt their first milk teeth at around 6 months of age, and all of them come out around the age of 3. The normal number of milk teeth is 20, and they basically come out at the age of 2.5 years. There are also differences in the timing and order of the eruption of milk teeth. If a baby is over one year old and still has not yet erupted teeth, the eruption of milk teeth is too late, and the baby should go to the stomatology department of the hospital in time for treatment of the symptoms. During the period of eruption of milk teeth, it is necessary to strengthen the nutrition and ensure the daily intake of vitamins. Daily life with the baby more sunshine, help calcium absorption, tooth eruption. Babies start to change permanent teeth at the age of five or six, and usually have between twenty-eight and thirty-two permanent teeth. If there is any abnormality in the eruption of the child’s teeth, it is recommended to go to the hospital in time, and parents should pay attention to the child’s oral hygiene.