Early loss of milk teeth can be harmful to a child’s growth and development, and children need to be fitted with gap retainers in a timely manner when they experience early loss of milk teeth. A gap retainer maintains normal physiologic gaps in children and prevents neighboring teeth from tilting toward the site of loss and opposing teeth from elongating. Gap retainers are used to maintain the proximal, distal, middle and vertical gaps in the teeth to maintain the normal eruption of the inherited permanent teeth. Therefore, it is important to wear gap retainers for children with premature loss of milk teeth, and it is also important to pay attention to oral hygiene.