| Field | Value |
|---|---|
| ID | OA-0312 |
| Type | space_maintainer |
| Category | space_maintenance |
| Fixed/removable | fixed (most common) or removable |
| Primary function | recovering lost arch space; distalizing drifted molars |
| Malocclusion target | space loss from premature primary tooth loss; mild crowding |
| Inventor | various |
| First year | mid-1900s |
| Period | historical / current |
| Status | current |
| Uses TADs | rarely |
A space regainer is prescribed when a primary tooth was lost prematurely and the adjacent teeth have already drifted, reducing space for the erupting permanent successor. Unlike a passive space maintainer, the space regainer contains an active element (coil spring, expansion screw, or active wire) that pushes or tips the drifted molar distally to re-open the space. Treatment must be completed before the permanent successor erupts and before the bone remodels too extensively around the drifted root.
The active component (typically a compressed open-coil NiTi spring or a helical loop) generates a continuous distal force on the mesially-drifted molar. The reaction force is absorbed by the anterior anchor tooth (usually via a band or crown). Force delivery is typically 50–150 g, producing gradual distal tipping of the molar crown over weeks to months. The appliance is activated at intervals until sufficient space is recovered, then converted to a passive space maintainer or removed when the permanent tooth erupts.
Recent mesial drift of a first permanent molar following premature second primary molar loss; cases where space loss is mild to moderate (< 4 mm) — severe loss may require comprehensive orthodontic management; mixed dentition with adequate root support on the anchor tooth; patient and parent compliance if a removable version is used. Radiographic verification that the permanent successor is still unerupted and there is sufficient time to recover space.
Space regaining is most effective in growing patients — adult cases have more cortical resistance. Cannot regain space in cases with ankylosed primary molars or adjacent teeth with significant root resorption. Severe space loss (> 4 mm) may exceed what a simple regainer can achieve — consider extraction management or comprehensive ortho instead. Patient compliance is essential for removable versions; fixed designs are preferred for reliability.
Fixed spring regainer (most common):
primary canine)
guide wire
to push the molar distally
Removable regainer:
For the fixed version: adapt both bands on the model, thread the guide wire through buccal tubes, and compress the NiTi open-coil spring to the prescribed activation (1–2 mm beyond passive length). Solder the distal stop on the guide wire to maintain activation. The simpler helical-loop version requires careful wire bending: the activated loop must deliver a measurable distal force without torquing the tooth. For removable versions, fabricate as a standard acrylic plate with a properly calibrated finger spring. CFL's Space Regainer is — positioned between a simple space maintainer and more complex expanders.
most predictable force delivery.
simpler fabrication.
patient-activated.
passive activation.
Denpedia](https://denpedia.com/space-regainer-appliances-types-applications-and-benefits/)
ResearchGate](https://www.researchgate.net/publication/313460235Spaceregainersinpediatric_dentistry)
PMC](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11600096/)
business notes.