The treatment of knocked loose milk teeth at the age of 5 depends on the front teeth and back teeth, and the general conventional front teeth replacement time is 6-8 years old. If knocked to the lower front teeth, knocked loose first to take pictures, depending on the root resorption, and the presence of root fracture, as follows: 1, if the root of the milk tooth has been absorbed to the upper 1/3 of the root, and the permanent tooth embryo is about to erupt, it may be necessary to extract the loose milk tooth, in favor of the child to eat. This is because the loose tooth will feel uncomfortable and reluctant to bite when the child eats; 2. If the permanent tooth germ is still erupting for a long time, it may be necessary to fix it, using resin plus wire to connect the tooth next to the loose baby tooth and fix it for 4-6 weeks.