Closed Coil NiTi with Eyelets for Orthodontic Made in USA
A NiTi closed coil spring is an orthodontic passive compressed spring made of super elastic Nickel Titanium. To facilitate its application, two round eyelets are attached to each side of the coil. It is an important element in every orthodontic office. Unlike SS closed coils, NiTi closed coils will better resist deformation under normal activation. IOS manufactures the coils in various length to accommodate the different needs by orthodontist. . All IOS NiTi coils are manufactured from super elastic NiTi.
Understanding the size of an orthodontic closed coil NiTi spring.
We will take a 12 mm closed coil spring as an example. The length represents the entire length of the coil and eyelets. It is NOT the length of the active spring portion. To calculate the actual active coil length, we need to deduct the size of the two eyelets “ 3 mm each”. So a 12 mm coil is actually 12 – 3 – 3 = 6 mm of active spring.
What are the clinical uses of closed coil NiTi ?
- Canine / Teeth retraction in extraction cases.
- En mass retraction to correct under bite
- Impacted canine retraction
- Vertical traction of Impacted premolars
- Intrusion of super erupted teeth with the use of mini implants
- Intrusion to correct a deep bite with the use of mini implants
- And more
How to measure forces delivered by the closed coil?
Force is usually measured per 1 mm of activation. In the dental office, a simple force gauge might be utilized to get an estimate of how much force is being delivered. IOS utilizes a digital force measuring device which is more accurate.
What are the factors that affects the force delivery?
- Wire diameter. The thicker the wire, the stronger force. Closed coil NiTi springs come in three wire sizes:
- 0.009” for light force
- 0.010” for medium force
- 0.011” for Heavy force
- The active coil length. Smaller springs will deliver more forces compared to longer springs.[REF]
- The amount of activation. The more the spring is stretched, the stronger the force would be delivered.
IOS manufactures and sells the closed coil NiTi Springs in different forces and lengths to accommodate the different orthodontics clinical needs.
| 9mm | 12 mm | 14 mm | 16 mm | 18mm | |
| Light | 14-152-009 | 14-152-012 | 14-152-014 | 14-152-016 | 14-152-018 |
| Medium | 14-153-009 | 14-153-012 | 14-153-014 | 14-153-016 | 14-153-018 |
| Heavy | 14-154-009 | 14-154-012 | 14-154-014 | 14-154-016 | 14-154-018 |
How to choose between a light vs heavy closed coil?
Research has shown that light forces for a single tooth traction will tend to move the tooth more efficiently with less anchorage loss[REF]. However, for en mass retraction, it is better to use medium to heavy coils as more forces is needed to move the teeth.
Why to use a closed coil NiTi over an elastomeric powerchain?
The major advantage of the NiTi spring is the constant force delivery. Elastomeric powerchain force tends to decay rapidly overtime to a point that affects its mechanical properties and clinical efficacy[REF]. Please note that even a NiTi coil spring will also suffer some force reduction in the patient mouth.[REF] However, this force reduction will not negate tooth movement.
