Understanding Fixed Elastics with Braces: Reasons & Benefits

Interarch Elastics (Rubber Bands) in Orthodontics

Fixed elastics connect upper and lower braces to correct jaw relationships and bite.

Common Indications

Malocclusion	Elastic Vector	Effect
Class II (overbite)	Upper canine → lower molar (Class II elastic)	Retracts upper, protracts lower
Class III (underbite)	Lower canine → upper molar (Class III elastic)	Retracts lower, protracts upper
Open bite	Vertical (triangle, box)	Extrudes anteriors, intrudes posteriors
Crossbite	Cross-arch (buccal-lingual)	Corrects transverse discrepancy
Midline shift	Asymmetric vectors	Centers dental midlines
Space closure	Hook-to-hook (power chain alternative)	Closes extraction spaces

Patient Compliance Is Critical

• Wear 20-22 hrs/day (except eating/brushing).
• Change 3-4x/day (lose force).
• Carry spares.
• Non-compliance = prolonged treatment, compromised result.

Side Effects

• Soreness (first 2-3 days).
• Root resorption (rare, with excessive force).
• Unintended tooth movement if misconfigured.

Elastics are the "steering wheel" of bite correction—patient-driven, orthodontist-prescribed.