Space management of the permanent dentition

We will focus on the various types of space maintainers, when and how they are used, and how they are made. Our coverage will center on maintaining existing space once primary teeth have been lost prematurely, rather than on tooth movement.

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. In other words, they need less patient compliance.

Removable appliance must be worn at least 14 hours per day. Hence, it is highly dependent on patient compliance. However, oral hygiene would be easier owing to its removable nature.

This photograph shows an example of a fixed unilateral appliance on the mandibular first molar using stainless steel wire soldered to an orthodontic band, with space being maintained for the underlying bicuspid. This appliance is referred to as a band and loop space maintainer and is a favorite among many pediatricians and general dentists. However, orthodontists usually prefer to use bilateral appliances due to their versatility following loss of other primary teeth and being less prone to removal and swallow with the child.

These are examples of dangerous space maintainers. They are removable unilateral space maintainers. We believe removable unilateral space maintainers should not be used. They are too small and present swallowing and choking dangers for children.

Distal shoe space maintainer or distal extension space maintainer is used to prevent first permanent molars from moving mesially with the premature loss of second primary molars. The example shown is a crown with a distal extension segment soldered to the crown. The distal segment is extended into the tissue against the unerupted first permanent molar.

This appliance is mostly used with pediatricians, but orthodontists are usually afraid of making problem for the first permanent molar instead of guiding its eruption via this appliance due to the common error in precise positioning of the distal extension part.

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.

This photograph shows an example of a fixed unilateral appliance constructed by a stainless steel wire soldered to an orthodontic band, with space being maintained for the underlying bicuspid. This appliance is referred to as a band and loop space maintainer.

As suggested previously, removable appliances are more dependent on patient compliance so prone to problems with the appliance not being worn and the frequent incidence of breakage and loss. However, they make oral hygiene more comfortable.