A space maintainer is made of stainless steel and/or plastic. It can be removable. Some space maintainers are cemented onto the teeth on either side of the space in the child’s mouth. This is called a fixed space maintainer.
A removable space maintainer looks like a retainer. It uses artificial teeth or plastic blocks to fill in the space or spaces that need to stay open. This type of space maintainer often is used when the space is obvious to other people. Removable space maintainers work well in older children who can reliably follow directions about caring for this appliance.
There are several kinds of fixed space maintainers. A band-and-loop maintainer is made of stainless steel wire. It is held in place by a crown on the tooth next to the space or an orthodontic-type band around one of the teeth next to the open space. A wire loop is attached to the band or crown. It sticks out across the space where the tooth is missing and just touches the tooth on the other side of the open space. The wire loop holds the space open. This allows the permanent tooth enough space to come into the mouth without crowding.
A lower wire known as a “lingual arch” is used when back teeth are lost on both sides of the lower jaw. “Lingual” refers to the inside or tongue side of the teeth. This type of space maintainer uses bands wrapped around a tooth on either side of the mouth behind the missing teeth. A wire connected to the bands runs along the inside of the bottom teeth, just touching them. This will maintain the space on both sides.
Another type of fixed space maintainer is called a distal shoe appliance. It is inserted under the gums. It is used when a child loses the baby tooth in front of a 6-year molar that has not yet come into the mouth. The 6-year molar is also called the first permanent molar. Because it has not come in yet, there is no tooth to hold a band-and-loop space maintainer in place. A distal shoe appliance has a metal wire that is inserted slightly under the gum. This keeps the space from closing.
Distal shoe appliances must be checked often because the incoming tooth can easily become blocked by the wire. The appliance may require adjustment to allow the tooth to come in properly. As a result, most dentists will try to avoid using a distal shoe appliance. Instead, they will try to keep the primary tooth in the mouth until the permanent tooth underneath is ready to come in.
For children missing several teeth, a partial denture may be used instead of a space maintainer. For example, children with a congenital disease called ectodermal dysplasia often are missing multiple primary teeth. There are no permanent teeth to replace them. A child with this condition will use a removable denture into adulthood. After that, the child can receive dental implants or a bridge or continue to use a partial denture to replace the missing teeth.