Some permanent teeth are located behind the milk teeth, and some of them grow in the position of replacing milk teeth. Normally, all milk teeth will be replaced by permanent teeth, and it is recommended to go to the hospital for specific examination and treatment if there is any problem during the tooth replacement period. There are 20 milk teeth, and all 20 of them will fall out and be replaced by permanent teeth. The milk incisors will be replaced with permanent incisors; the milk lateral incisors will be replaced with permanent lateral incisors; the milk cuspids will be replaced with cuspids; the first molar will be replaced with the first premolar; and the second molar will be replaced with the second premolar. All of these erupt essentially in their original positions, with individual malocclusions having positional changes. Behind the milk teeth will grow the first molar, the second molar, and in some cases the third molar, also known as wisdom teeth.