The rubber bands on braces go by several names depending on which type you’re looking at. The small colored ones wrapped around each bracket are called ligatures (also known as elastic ligatures, O-rings, or elastic modules). The larger bands that stretch between your upper and lower jaws are called interarch elastics. Most people use “rubber bands” as a catch-all, but these two types serve completely different purposes.
Ligatures: The Small Bands on Each Bracket
Ligatures are the tiny elastic rings your orthodontist places around every individual bracket. Their job is straightforward: they hold the archwire inside the bracket’s slot so it can apply steady pressure to move your teeth. Without them, the wire would simply pop out.
These are the bands most people picture when they think of braces. They come in dozens of colors, which is why picking new colors at each adjustment appointment becomes a small ritual for many patients. You’ll also hear them called elastic modules or O-rings. They’re softer than the metal wire alternatives (called steel ligatures), exert less force on the bracket, and are faster for the orthodontist to place and remove.
One thing to know: ligatures lose some of their stretch over time. That’s part of why adjustment appointments happen every several weeks. Your orthodontist replaces them with fresh ones to maintain consistent pressure on your teeth.
Interarch Elastics: The Jaw-Connecting Bands
Interarch elastics are the rubber bands that hook from a bracket or hook on your upper teeth to one on your lower teeth. They work across both arches of your jaw, which is where the name comes from. Their purpose is to correct your bite by guiding your upper and lower jaws into proper alignment.
Unlike ligatures, which your orthodontist handles entirely, interarch elastics are your responsibility. You remove them to eat and brush, then put fresh ones back in. Most people wear them nearly all the time, though some only need them at night. They lose their elasticity with use, so you’ll typically change them multiple times a day based on your orthodontist’s instructions. Skipping wear time is one of the most common reasons orthodontic treatment takes longer than planned.
Power Chains
Power chains are a series of connected elastic rings that look like a tiny chain of linked O-rings. Think of them as multiple ligatures fused together into one continuous strip. They stretch across several brackets at once, applying steady pressure to close gaps between teeth. They’re particularly common after a tooth extraction, where there’s a visible space that needs to close, or for general spacing issues.
The key difference from individual ligatures is that power chains create a pulling force between teeth rather than just holding the wire in place. Like regular ligatures, they come in various colors and are swapped out at adjustment appointments as they lose tension.
Separators (Spacers)
Before braces go on, some patients get small rubber rings called separators or spacers wedged between their back molars. These aren’t technically part of braces themselves, but they’re another “rubber band” you’ll encounter during treatment. Their job is to push molars slightly apart over a few days to create enough room for metal bands (the rings that wrap around back teeth) to fit.
Separators typically cause tenderness for the first few days as teeth shift. During that time, soft foods help, and you should avoid anything sticky or chewy that could pull them out. You brush normally but skip flossing around the areas where separators sit. If one falls out before your next appointment, call your orthodontist, because the space may close back up.
Latex vs. Non-Latex Options
Most traditional orthodontic elastics are made from natural rubber latex, composed of roughly 90 to 95% natural rubber with small amounts of colorant and a vulcanizing agent that gives the material its stretch and durability. For patients with latex allergies, non-latex alternatives made from synthetic polymers are widely available.
The two materials behave slightly differently. Latex elastics maintain their force more consistently because of stronger molecular bonds in the material. Non-latex versions rely on weaker bonds, which means they tend to lose tension a bit faster. In practice, this just means your orthodontist may adjust how often you change them. Both get the job done, so a latex allergy won’t limit your treatment options.