A tree can grow leaves twice or more times a year, while human teeth only have two growth processes in a lifetime: one is milk teeth; the second is permanent teeth. Functions of milk teeth: 1, chewing function in pediatric period. 2.Promote the development of jawbone in pediatric period. 3, affect the pediatric period of the face shape. 4.Protect the safe eruption of permanent teeth. 5, guide the normal eruption of permanent teeth. To pay attention to the following aspects: 1, the time of eruption of milk teeth, generally about 0.5 years of age began to erupt, until about 3 years of age, the lower teeth of the homonymous teeth erupt before the upper teeth. 2, the number is 20. 3, should often look at the child’s milk teeth, see whether the color darkened, black, that is, “worm teeth”. (It is best to go to the dental clinic every six months to a year to do a health check, early detection, early treatment) 4, milk teeth are normal to the age of 6 years old, only began to fall off naturally, do not artificially premature extraction. 5, to see if the “pericoronation”, that is, anticoronation. Any one or more of the above reasons should be consulted to make the corresponding treatment, such as: the fossa sealing of milk teeth (every milk tooth can be done), endodontic treatment of milk teeth (found pain or discoloration), orthodontic treatment of milk teeth (at the age of 3.5 years old can be) and so on.