At the age of 6, the baby teeth will gradually loosen and fall out, while the permanent teeth will slowly come in. Nowadays, because children generally have better nutrition and better development, they may start to replace their teeth at the age of 5, which is normal and parents need not worry too much. However, there are some children, the time of tooth replacement will be a little later, about 7-8 years old to start replacing teeth, as long as other aspects of development indicators are normal, a little earlier or later tooth replacement does not need to worry too much. The process of replacing baby teeth with permanent teeth will last until about 12-13 years old, when all the teeth are basically replaced. In the process of tooth replacement, we should pay attention to maintaining good oral hygiene and good dental habits, which will facilitate the eruption and development of permanent teeth.