Band and loop space maintainer.
Why some children need space maintainers? When children lose baby teeth earlier than expected for some reasons like decay or injury, a space maintainer will hold the spot left by the baby tooth and keep the space available until the permanent tooth emerges. Baby teeth are important to the development of the teeth, jaw bones and muscles and help to guide permanent teeth into position. If a space is not maintained, then teeth can shift into the open space and orthodontic treatment may be required.
This child lost the baby molar tooth due to severe decay and a band and loop space maintainer was cemented as a passive device, meaning it does not move teeth, so there is no pain associated with it.
Once the permanent tooth is ready to erupt, the space maintainer will be removed, and the new tooth will take its place without crowding the teeth around it.