Orthodontic elastics, often called rubber bands, are a component of braces treatment that performs a job distinct from the metal wires and brackets. While the archwire and brackets primarily work to straighten individual teeth within the upper or lower arch, elastics focus on correcting how the upper and lower arches fit together. These small, removable bands are stretched between hooks on the braces to apply a specific, gentle force. Their main purpose is to guide the entire bite into a proper, functional alignment.
How Elastics Apply Force to the Jaw
Elastics introduce an inter-arch force, applying pressure between the upper and lower jaws. This biomechanical action is separate from the forces exerted by the archwire, which only aligns teeth along the same curve and does not influence the relationship between the two dental arches. The rubber bands connect to specialized hooks or posts on the brackets, creating tension that spans across the bite.
The consistent, light tension generated by the elastic band creates orthopedic pressure that guides the bone and teeth of one arch relative to the other. This movement can involve shifting an entire dental arch forward or backward to achieve the correct meeting of the front and back teeth.
This continuous gentle force is necessary because the bones supporting the teeth require steady, sustained pressure to remodel and move into a new position. The goal is to establish a harmonious relationship between the upper and lower jaw, ensuring the teeth mesh correctly when biting down.
Different Types of Elastic Configurations
The specific pattern in which elastics are worn dictates the direction of the force and the type of bite issue being corrected.
Class II Elastics
This is one of the most common configurations, used to correct an overbite where the upper teeth protrude over the lower teeth. These elastics typically run from a hook near the upper canine tooth to a hook on a back molar of the lower arch. This configuration pulls the upper teeth backward, the lower teeth forward, or both.
Class III Elastics
This opposite configuration is prescribed for an underbite, where the lower jaw sits too far forward. The elastic is stretched from a lower canine or premolar forward to a hook on an upper back molar. This pattern creates a force that pulls the lower arch backward while encouraging the upper arch to move forward.
Other Configurations
Other patterns address localized alignment issues.
- Vertical elastics are stretched vertically between opposing teeth to close a gap or fix an open bite.
- Box or triangular elastics connect three or four points in a tight pattern to settle the final position of a group of teeth.
The precise hook placement and size of the elastic are customized to the patient’s needs to ensure the force is applied accurately.
Patient Compliance and Daily Care
The effectiveness of orthodontic elastics depends entirely on the patient’s commitment to consistent wear. The recommended wear time is typically 20 to 22 hours per day, with removal only for eating and routine oral hygiene. Wearing elastics only at night is insufficient, as intermittent pressure allows teeth to shift back toward their original positions, stalling progress.
Elastics lose their tension and elasticity quickly due to constant stretching and exposure to saliva and heat. For this reason, the bands must be changed out for fresh ones multiple times a day, often three to four times, to ensure the force remains at the prescribed level. Reusing old bands provides less force and slows down the treatment timeline.
Failing to adhere to the wear schedule can lead to significant delays in treatment. Irregular wear causes a back-and-forth movement that the supporting bone resists, making the process less effective. Patients must wear the elastics exactly as instructed to ensure the continuous force necessary for corrected bite alignment.