The reasons for the wide gap between children’s teeth are as follows: 1, with the rapid development of the child’s jaw and face, the length and width of the dental arch gradually increase, due to the size of the crowns of the milk teeth will not change significantly, can be formed in scattered gaps for the eruption of the permanent teeth to get ready for the emergence of the permanent teeth. 2, part of the child’s lip and cheek tie or tongue tie attachment site is low, coarse fibrous tissues can impede the gap to close the gap, only to carry out a tie revision surgery, cut off the fiber! The gap can only be narrowed after a ligament revision surgery to cut off the fibers.3. After the premature loss of milk teeth, there will be a large gap in the dental arch. If the tooth germ is congenitally missing or formed too small teeth, the teeth are sparsely arranged and easily embedded with food debris. Due to the thin enamel and dentin of milk teeth, it is easy to produce neighboring surface caries, and rapidly expand into residual roots, crowns, and so on.