It is a fixed custom-made appliance in metal, cemented in the child oral cavity. It keeps the space arising due to premature loss of milk teeth (for any reason) open and preserved. This allow the permanent tooth erupt in correct place and position, which otherwise might contribute to crowding the permanent teeth.
Child needs a space maintainer if the milk tooth removed earlier due to dental decay or any reasons. As the child’s jaw is undergoing constant growth, the premature loss of a primary tooth will be utilized the erupted or erupting teeth. This would cause loss of space and crowding in the permanent set of teeth.
Normally milk teeth are important to the development of the teeth and helps to guide for the permanent teeth erupts. When the milk teeth are removed earlier due to dental decay, if the space is not maintained, then the other teeth can be shifted into the open space. So the particular tooth cannot erupt due to lack of space.
The child might get some time to initially adjust this custom made material in the mouth for a day and after which this do not cause any issues.