If a primary tooth, especially a back primary tooth (molar) is extracted (pulled) early, a Space Maintainer is needed. A space maintainer is an appliance that is custom-made by a dentist or orthodontist in acrylic or metal material. It can be either removable or cemented in a child’s mouth. Its purpose is to keep the space open to allow the permanent tooth to erupt and come into place. If a space is not maintained, then teeth can shift into the open space and orthodontic treatment may be required at a later stage.