Space Maintainers

Space maintainers are appliances used in the mouth to preserve and maintain space. They are necessary when one or more primary molars have been prematurely lost due to trauma or disease. Using a space maintainer allows the permanent teeth to erupt, or grow, into the correct alignment with proper tooth-to-tooth contact. It isn’t usually necessary to use a space maintainer when front teeth are lost prematurely, although removable partial dentures may be prescribed as space maintainers if several front teeth are missing and a child’s appearance is affected.

When properly used, space maintainers can prevent movement of the first molars, preventing loss of space for other teeth, including adult bicuspid and canines, which are permanent. If the permanent first molars are not held in the correct positions they can begin to drift forward, stopping the bicuspid teeth from erupting properly. The first bicuspids may also move forward, blocking the way for the permanent canines to erupt correctly. There are many types of space maintainers that may be used, depending on the location of the tooth and the needs of the patient.

Different Types of Space Maintainers

Generally, fixed space maintainers are used by cementing onto the tooth. They cannot be removed by the patient, increasing their long-term effectiveness. Fixed space maintainers include the band and loop, the TransPalatal arch, the distal shoe and the lingual holding arch.
One of the most straightforward space maintainers is the band and loop, where a metal band is fitted around an abutment tooth and is attached to a wire loop that touches the other abutment tooth, preventing movement. This type of space maintainer is used when a primary molar has been removed. A crown and loop is a similar type of space maintainer, but it utilizes a dental crown fitted over a badly decayed abutment tooth. One problem with this type of space maintainer is that adjustments can often be difficult.

A TransPalatal arch is used for bilateral loss of primary maxillary molars. It consists of two metal bands connected across the palate with a rigid wire. The metal bands are fitted onto the nearby teeth, preventing forward movement. Although this space maintainer is hygienic, it may not prevent mesial tipping, which is the leaning of teeth that can result in crooked angles. When an acrylic button is added to this space maintainer it becomes a Nance appliance, but this button can create oral hygiene problems.

A distal shoe space maintainer is used when a patient is too young to have their permanent first molars. With this appliance, a distal shoe is placed onto a baby molar, projecting through the gums to the mesial surface of the still-hiding first molar, guiding its eruption into the mouth.

A lower lingual arch is used when one or more primary molars are missing from both sides of the arch and when the permanent first molars have already erupted. This space maintainer uses metal bands fitted around the permanent first molars and a wire, which is bent into the shape of the arch, is soldered onto the bands. This wire is fitted inside the child’s front teeth.