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General product and regulatory information for lab, clinic and supply staff. It is not medical advice and does not describe how to use an appliance on a patient.
Short answer
An orthodontic spring is a spring component used in orthodontic appliances to exert pressure on teeth. In the United States, FDA lists it as “spring, orthodontic” (product code ECO), a Class I device under 21 CFR 872.5410, exempt from premarket notification. Force labels such as “light” or “heavy” are not standardized between suppliers, so a spec sheet’s stated load matters more than the label word.
Definition and scope
The regulation 21 CFR 872.5410, “Orthodontic appliance and accessories,” identifies the device as one “intended for use in orthodontic treatment” that “is affixed to a tooth so that pressure can be exerted on the teeth.” The regulation covers a family of parts, and springs are named alongside bands, brackets, tubes and wires. A spring is therefore a component category inside a shared regulation, not a separately regulated device type.
Other pages on CASRAI cover the neighbouring components: the orthodontic bracket, orthodontic archwire, orthodontic band, orthodontic separators and the orthodontic power chain. This page stays with springs and the way their regulatory identity and force documentation work.
How FDA classifies an orthodontic spring (product code ECO)
The FDA Product Classification database and the openFDA classification endpoint (both checked 2026-10-31) agree on the following.
| Field | Entry for product code ECO |
|---|---|
| Device name | Spring, orthodontic |
| Regulation | 21 CFR 872.5410, Orthodontic appliance and accessories |
| Device class | Class I (general controls) |
| Review panel | Dental |
| 510(k) | Exempt, subject to the limitations in 21 CFR 872.9 |
| GMP exempt | No |
| Implanted / life-sustaining | No / No |
| Summary malfunction reporting | Eligible |
Class I with a 510(k) exemption means FDA does not require a premarket notification for these springs, within the limits of 21 CFR 872.9. The “GMP exempt: No” entry means the product code is not exempt from the quality system requirements, so a manufacturer is still expected to operate under them.
How springs are used and what is measured about them
In orthodontics, springs are components that supply force within an appliance. This page does not cover clinical selection or technique. What can be said from published measurement is how the force of one common type, the nickel-titanium (NiTi) closed coil spring, behaves in the laboratory.
Maganzini, Wong and Ahmed (Angle Orthodontist 2010;80(1):182-187) tested 14 types of 9 mm NiTi closed coil springs from five suppliers, five specimens each (70 in total), at 37 °C. Their findings:
- Peak load at 12 mm extension “varied from 147 to 474 grams” across the 14 products.
- Only 6 of the 14 met the study’s constant-force criterion (a mean unloading force change of 50 g or less between 9 mm and 3 mm). The GAC 100 changed least (17 g) and the RMO 0.011 inch changed most (107 g).
- Mean unloading forces measured at 9, 6 and 3 mm of deactivation were highly variable between products, and the authors concluded that few springs showed both physiologic peak load forces and constant deactivation forces.
Types and related concepts
The laboratory data cited here concern closed coil springs, so the table below is limited to what that study and the regulation support.
| Concept | What the sources say |
|---|---|
| NiTi closed coil spring | Tested as 9 mm coils; peak load 147 to 474 g across 14 products; 6 of 14 near-constant unloading force (Maganzini et al. 2010). |
| Spring as a regulatory category | One of the part types named in 21 CFR 872.5410, with product code ECO. |
Where it matters for labs, clinics and supply decisions
The study’s most useful finding for anyone reading product documentation is about labeling. The authors report that products used terms such as “Ultra Light, Light, Medium, Heavy, and Extra Heavy,” and conclude that “the present labeling of nickel titanium closed coil springs is confusing and may be misleading.” They also note that few springs tested showed both physiologic peak load forces and constant deactivation forces.
Documentation questions this supports
These are questions to put to the manufacturer’s documentation, drawn from what the study measured. They are not a ranking of products.
- What material is the spring, and over what coil length was the stated load measured?
- Is the stated force a peak load or an unloading force, and at what deflection?
- Does the supplier publish force-deflection data, or only a descriptive word such as “light” or “medium”?
- Is the product listed by the manufacturer under 21 CFR 872.5410 and product code ECO?
The study tested products from five suppliers and was published in 2010; it does not establish how any product on the market today performs, so current data must come from the manufacturer.
Common misunderstandings
- “Class I means standardized force.” Class I and 510(k) exemption describe FDA’s level of premarket control. They do not set a force range or a labeling vocabulary, and the 2010 measurements show wide spread between products with similar label words.
- A spring is not a retainer. A removable retainer that includes wire elements is a different appliance type; see orthodontic retainer types.
- A spring is not an expansion screw. Screw-based expanders have their own product code (DYJ for the expansion screw retainer); see orthodontic expander types.
FAQ
Is an orthodontic spring an FDA-regulated medical device?
Yes. FDA lists “spring, orthodontic” under product code ECO and 21 CFR 872.5410 as a Class I device, exempt from premarket notification subject to 21 CFR 872.9 (FDA records checked 2026-10-31).
Do light, medium and heavy labels mean the same force at every supplier?
Not according to the published laboratory study cited on this page. Peak loads across 14 NiTi closed coil springs ranged from 147 to 474 g, and the authors called the labeling confusing and potentially misleading.
Sources
- eCFR, 21 CFR 872.5410, Orthodontic appliance and accessories, ecfr.gov, checked 2026-10-31.
- FDA Product Classification database, product code ECO, accessdata.fda.gov, checked 2026-10-31.
- openFDA device classification endpoint, product code ECO, api.fda.gov, checked 2026-10-31.
- Maganzini AL, Wong AM, Ahmed MK. Forces of Various Nickel Titanium Closed Coil Springs. Angle Orthodontist 2010;80(1):182-187, PMC8978725, DOI 10.2319/011509-592.1, checked 2026-10-31.
