| Field | Value |
|---|---|
| ID | OA-0189 |
| Type | component |
| Category | component |
| Fixed/removable | fixed (placed at adjustment) |
| Primary function | retain archwire in bracket slot |
| Uses TADs | no |
Elastic ligatures (O-rings, modules) are the most common method of securing the archwire in the bracket slot. A small polyurethane or latex ring is stretched over the bracket tie-wings with a ligature director, cinching the archwire into the slot. Elastic ligatures generate friction against the archwire, which can resist sliding mechanics but can be used advantageously for rotation control. Low-friction modules (e.g., slide ligatures) reduce friction to facilitate sliding mechanics. Available in clear, white, silver, and a full range of colors — patients often choose colors at each appointment.
Ligatures are the interface between the archwire and the bracket — the mechanism that seats the wire into the bracket slot and engages the bracket's torque and tip prescriptions. Ligature choice directly affects friction, which in turn affects the force transmitted to the tooth and the efficiency of tooth movement.
Elastomeric modules (O-rings): The most common ligature in contemporary practice. Fast to place, color-customizable, and adequate for most alignment and leveling mechanics. The primary limitation is friction — elastomeric ligatures grip the archwire, which impedes sliding mechanics during space closure. Force also degrades by 50–70% within 24 hours of placement, so the ligature is retaining the wire rather than actively engaging it after the first day.
Stainless steel ligatures (0.009"–0.010" SS wire): Lower friction than elastomeric; preferred for sliding mechanics and space closure. Figure-8 tying pattern reduces friction further by keeping the wire contact point away from the slot floor. Cinching the wire end (tucking it under adjacent ligatures) prevents poking. More technique-sensitive and time-consuming than modules.
Loose vs. tied ligatures: Over-tied ligatures add friction without adding clinically meaningful engagement. Under-tied ligatures allow the wire to escape the slot. The target is full engagement without excess friction.
Sliding mechanics → steel ligatures or self-ligating brackets. Leveling and alignment → elastomeric modules acceptable. Rotations and torque → full engagement with steel ligature preferred. Aesthetic cases → tooth-colored elastomeric modules.
Elastomeric ligatures cause greater friction than steel in space-closure stages, slowing treatment. Colored elastomeric modules stain with food and beverages. Steel ligatures require careful wire-end management to prevent soft tissue injury.
No lab fabrication. Manufactured product; placed chairside.
Appliances that incorporate this component. ★ = fabricated by Clear Fusion Lab.
ring; most common; one per bracket
0.010" SS wire twisted around tie-wings; more precise torque engagement than elastomeric
pediatric/teen cases for patient engagement
around two adjacent brackets; ties teeth together
Clarity SL); clip mechanism holds archwire
Orthodontics](https://www.americanortho.com/product-category/ligatures/)