| Field | Value |
|---|---|
| ID | OA-0200 |
| Type | component |
| Category | component |
| Fixed/removable | component in removable appliance |
| Primary function | labial tipping of palatally displaced teeth |
| Malocclusion target | anterior crossbite (individual teeth); lingual incisor position |
| Uses TADs | no |
The Z-spring (double-cantilever spring) is bent from 0.5–0.6 mm SS wire in a Z shape: one arm lies against the palatal surface of the tooth, the other arm serves as a guiding return, and the whole spring is activated by the labially directed spring force. It is most commonly used to tip palatally displaced upper incisors labially out of crossbite. A common indication is the single tooth anterior crossbite in a growing child with a removable plate. The Z-spring is gently activated (adjusted outward) at each visit to maintain a light tipping force.
The Z-spring (double cantilever spring) generates labial force from a palatally positioned spring body embedded in the baseplate. Two horizontal cantilever arms project labially from a coiled midpoint, applying force to the palatal surface of one or two adjacent teeth simultaneously. The double-arm configuration delivers a more even, bilateral force than a single finger spring and reduces the tendency for the tooth to rotate as it moves labially.
The Z-spring is the preferred active element for moving palatally displaced maxillary incisors labially — one of the most common presentations in growing patients (Class I crowding or early crossbite of individual teeth). It is also used in functional appliances to procline upper incisors as part of Class II correction mechanics. A Z-spring on both upper central incisors can close a traumatically induced diastema or reopen labially displaced incisors after arch constriction.
Wire gauge 0.5 mm for light force (single incisor); 0.6 mm for two adjacent teeth. The spring is activated by pulling the arms labially before insertion, so the arms apply a labial force when the appliance is seated. The active arm length and the degree of activation determine force magnitude; 25–60 g per tooth is the clinical target.
Like all removable appliance springs, Z-springs produce tipping movement only. They are effective in the growing dentition where alveolar bone remodels rapidly; adult treatment with removable springs is less efficient and more relapse-prone. Over-activation beyond 2–3 mm per adjustment risks patient discomfort and spring deformation.
Lab-bent; embedded in acrylic baseplate.
Appliances that incorporate this component. ★ = fabricated by Clear Fusion Lab.
Acrylic plate retainer
appliance
appliance
delivers labial force on a single tooth
simultaneously
impingement
to deliver rotational force component
lingual; delivers labial movement from palatal baseplate
Orthodontics](https://www.elsevier.com)