What is the Composition of Invisalign?

 Align Technology, Inc. Aligner Material

2. COMPOSITION/ INFORMATION ON INGREDIENTS
2.1. Polyurethane from methylene diphenyl diisocyanate and 1,6-hexanediol. CAS# 137873-51-9
2.2. Additives

3. HAZARDS INDENTIFICATION
3.1. EMERGENCY OVERVIEW
3.1.1. This product consists primarily of high molecular weight polymers which are not expected to be hazardous.
3.1.2. Can burn in a fire creating dense, toxic smoke.
3.1.3. Molten plastic can cause severe burns.
3.1.4. Odorless.
3.1.5. No significant immediate hazards for emergency response are known.

3.2. POTENTIAL HEALTH EFFECTS (See Section 11 for toxicological data.)
3.2.1. EYE: Solid or dust may cause irritation or corneal injury due to mechanical action. Elevated temperatures may generate vapor levels sufficient to cause eye irritation.
3.2.2. SKIN: Essentially nonirritating to skin. Mechanical injury only. Molten material may burn skin. Skin absorption is unlikely due to physical properties.
3.2.3. INGESTION: Single dose oral toxicity is considered to be extremely low. No hazards anticipated from swallowing small amounts incidental to normal handling operations.
3.3. INHALATION: Dust may cause irritation of the upper respiratory tract. At room temperature, Exposure to vapors is unlikely due to physical properties:
 

Invisalign trays (aligners) are made of  mostly Polyurethane from methylene diphenyl diisocyanate and 1,6-hexanediol.  They are hypo-allergic, and biologically stable.
 

I will try to be as specific as possible from the Invisalign MSDS (material safety sheet).  Invisalign aligners are made of mostly Polyurethane from methylene diphenyl diisocyanate and 1,6-hexanediol.  What this really means is that its a medical grade polymer or plastic with some additives that change the properties of the material making it clear, strong, thin and flexible.  An ideal material to use in the oral cavity as it is hypo-allergic, inert and biologically stable.