Why are My Clear Aligners Yellow?

One of the attractions of having your crooked teeth straightened by Invisalign aligners (removable biocompatible plastic trays that gently push your teeth towards a straighter bite) is that they are almost invisible. None of those traditional brace contraptions and maybe only your best friends know you are undergoing an orthodontic treatment.

Cleaning Practices

But aligners can start yellowing or take on other colors unless you clean them and your teeth the correct way. There are 500-700 species of bacteria in anyone’s mouth, some of the harmful ones thriving on food particles (especially sugars and starchy simple carbohydrates like refined flour) that are not brushed and flossed off after meals. A bacterial film quickly forms that starts a periodontal (gum) infection, leading to cavities and irritation of the gums, which gradually pull away their support for teeth until they can fall out or need to be extracted.

Plaque on Teeth

Unless you have been rigorous about brushing and flossing, it is easy for a bit of plaque to remain on teeth and become transferred to the Invisalign aligners, which are microscopically porous and press against the teeth to slowly move them into their new positions. Saliva is mostly water but has a small amount of minerals, proteins, mucus, and enzymes that can dry to a yellow color and become trapped between the aligners and your teeth.

Other substances can also stain teeth and aligners, such as coffee, tea, red wine, sodas, blueberries, and tomatoes. So can certain mouthwashes. 

Maintain Your Aligners

It is important to not only change out your aligners every few weeks when you receive the new set but to clean them after taking them out of your mouth for meals, using soap and warm water (hot water can distort the trays). 

At night, before you go to sleep with them on, use denture tablets or retainer cleanser to soak them in for  20 minutes. Food grade 3% hydrogen peroxide can also be used if it is diluted one part to two of distilled water (since hard water can leave minerals on the porous plastic). If stains remain, scrub them with a toothbrush (but not the one you use twice daily!).

Remember that the best way to keep your teeth and gums healthy and your aligners free of stains and bacteria is to brush for two minutes after breakfast (bacteria builds up in the mouth overnight) and two minutes after your last snack, when you also floss.