
This photograph shows an example of a fixed unilateral appliance. The
photograph demonstrates the appliance after cementation. This appliance
is referred to as a band and loop space maintainer and is a favorite among
many clinicians.
This photograph shows an example of a fixed bilateral space maintainer. The appliance is cemented on the two second primary molars. Fixed bilateral space maintainers on the mandibular arch often are called lingual arch space maintainers. Mandibular fixed bilateral space appliances generally are preferred by clinicians over removable space maintainers. Fixed appliances are easier
to maintain and they are less likely to be removed, damaged, or lost by the child.

The photograph shows a maxillary fixed bilateral space maintainer. This type of space maintainer also is known as a Nance Holding Arch or a Nance Appliance. Note the small acrylic button which will rest against the palatal tissue with this appliance. Some clinicians object to the button since it can create tissue irritation. Therefore, it is important that patients and parents be instructed to make sure that the patient meticulously flosses under the acrylic button. The Nance Holding Arch is used in situations where premature bilateral loss of maxillary primary teeth has occurred.