Sometimes, primary (baby) teeth are lost prematurely due to trauma or decay.  Adjacent teeth tend to shift to fill the space, causing spacing and alignment problems for permanent (adult) teeth.  Space maintainers or “spacers” are inserted as placeholders until the permanent teeth are ready to erupt.  There are two main types of space maintainer:

• Fixed space maintainers – Depending on the position of the missing tooth and the condition of the surrounding teeth, the pediatric dentist may adhere a “band and loop,” a “crown and loop,” or a “distal shoe” type of spacer to fill the empty gap.  All spacers fulfill the same function; just the nature of the attachment to the adjacent teeth differs.  Fixed spacers are usually made of metal and are highly durable.  
• Removable space maintainers – Removable spacers are rarely used with young children.  Working a little like orthodontic retainers, special plastic parts fit into the empty slot to prevent the “drifting” of adjacent teeth.