Class II elasticsresearched

Quick facts

Field	Value
ID	OA-0126
Type	component
Category	component
Fixed/removable	removable (patient-worn)
Primary function	Class II molar/canine correction
Malocclusion target	Class II malocclusion
Compliance required	yes — 20–22 hours/day
Uses TADs	no (can be combined with TADs)

Overview

Class II elastics are intermaxillary elastics worn from the upper arch (typically upper canine or first premolar hook) to the lower arch (typically lower first molar hook), running in a Class II direction — from the front of the upper arch to the back of the lower arch. The elastic delivers a mesial force on the lower arch (forward) and a distal force on the upper arch (backward), correcting a Class II molar and canine relationship. Class II elastics are the most patient-dependent Class II correction mechanism — effectiveness is entirely compliance-driven. They are the simplest and lowest-cost Class II correction adjunct in fixed appliance treatment.

Clinical & technical

Mechanism of action

The stretched elastic delivers a continuous force (typically 2–4 oz per side) along the Class II vector. The mesial component on the lower arch moves lower molars forward and tips lower incisors labially. The distal component on the upper arch tips upper molars distally and tips upper incisors palatally. The net effect reduces overjet and corrects the molar/canine relationship. Ideally worn 20–22 hours/day; worn only when sleeping produces minimal effect.

Indications & case selection

Class II molar and canine correction in compliant patients; early and comprehensive treatment; combination with fixed appliances; patients willing and able to wear elastics full-time; mild-to-moderate Class II correction (severe Class II may require fixed functional appliances).

Contraindications & limitations

Entirely compliance-dependent — non-compliant patients see no correction; can tip rather than translate teeth if not combined with appropriate archwire mechanics; excessive force or incorrect attachment points produce undesirable tooth movements (excessive anterior proclination, bite opening).

Design & fabrication

Components & materials

• Latex or non-latex (for latex allergy) rubber elastics
• Multiple sizes: 1/8″, 3/16″, 1/4″ diameter; multiple forces (2, 3.5,

4 oz)

• Standard hook on upper canine bracket; standard tube hook on lower

molar band

• Packaged in small bags; patient replaces daily (or more frequently

if elastic fatigues)

Lab fabrication notes

Elastics are manufactured by orthodontic suppliers (American Orthodontics, Ormco, TP Orthodontics, etc.) and dispensed chairside. No lab fabrication required.

Common variants & modifications

• Class III elastics — reverse direction Class III elastics
• Box elastics — worn in a box configuration for bite correction

and rotation

• Triangle elastics — three-point attachment for combined

correction

• Vertical elastics — for open bite closure

Used in

Appliances that incorporate this component. ★ = fabricated by Clear Fusion Lab.

• ★ ACCO appliance — ACCO appliance
• ★ Celtic appliance — Celtic

appliance

• Carriere Motion — Carriere Motion
• Herbst appliance — Herbst appliance

(pre-treatment)

• MARA — MARA appliance
• Forsus — Forsus

Common variants & modifications

• Short Class II elastic: maximal force per unit of stretch; used

for rapid correction, often 3/16" diameter

• Medium Class II elastic: 1/4" diameter standard; most common

clinical size

• Long Class II elastic: 5/16" diameter; lower force, more

comfort; better for lighter forces or anchorage-sensitive cases

• Triangle elastic (Class II variant): runs from upper canine to

lower first molar and lower canine — adds vertical and Class II force simultaneously

• Box elastic: rectangular configuration engaging upper and lower

posteriors; combines vertical and Class II forces

Also known as

• Class II elastics (commonname)_
• intermaxillary elastics (descriptor)
• rubber bands (patientterm)_

Sources

• [Orthodontic Headgear Types — New

Mouth](https://www.newmouth.com/orthodontics/treatment/headgear/)

Research log

• 2026-06-09 — researched Class II elastic mechanism, compliance

requirements, force specifications.