Short answer: Clear aligners usually turn yellow or stain when something other than water is consumed while they are in, when they are not cleaned well enough, or when plaque and saliva deposits build up on the aligner surface. Drinking only water while wearing the aligner and cleaning it regularly reduce this problem in most cases. When to move on to a new aligner is decided by the dentist according to the treatment plan, not according to the staining.
Why does an aligner turn yellow or stain?
Aligners are made from a thin, transparent material. This material can pick up colour when it is in contact with coloured drinks and foods for a long time. The main causes are:
- Coloured drinks with the aligner in: Drinks such as tea, coffee, cola, fruit juice and drinkable yoghurt fill the inside of the aligner and stay between the tooth and the aligner.
- Eating with the aligner in: Food debris gets trapped inside the aligner, causing both discolouration and a bad smell.
- Inadequate cleaning: If the aligner is not cleaned every day, a thin film forms on its surface; over time this film makes it look cloudy and yellow.
- Putting the aligner in without brushing your teeth: Debris on the tooth surface is trapped directly inside the aligner.
- Cigarettes and tobacco products: These can cause staining on both the teeth and the aligner. See our article on the effects of smoking on teeth.
What can you do to keep your aligner clear?
Only water with the aligner in
This is the key rule: while the aligner is in your mouth, drink only plain water. For everything else, take the aligner out, brush your teeth after eating or drinking, or at least rinse your mouth well with water, and then put the aligner back in. For your daily meal routine, we have prepared the article what can you eat and drink with clear aligners?
Regular, gentle cleaning
- Rinse the aligner with cold or lukewarm water every time you take it out; hot water can distort its shape.
- At least once a day, gently clean the inner and outer surfaces of the aligner with a soft brush.
- Abrasive toothpastes can scratch the aligner surface and increase cloudiness; use the cleaning method your dentist recommends.
- Do not use coloured mouthwashes while the aligner is in.
- When the aligner is not in your mouth, always keep it in its case; aligners wrapped in a napkin both get dirty and get lost.
For step-by-step cleaning, take a look at our clear aligner use and care guide and the daily care card you can carry with you.
Oral hygiene
Brushing your teeth and flossing before putting the aligner in protects both your teeth and your aligner. For oral hygiene tips, see the article on oral hygiene while wearing clear aligners.
What do a bad smell and cloudiness indicate?
If, in addition to yellowing, you notice a bad smell, a white chalky layer or clear cloudiness on the aligner, this usually shows that the cleaning routine is not sufficient or that the aligner has been stored dry for a long time. In this case, review your cleaning steps, keep the aligner in its case and consult the clinic if the problem continues. Also let your dentist know if there are sores or a burning feeling in the mouth or redness of the gums.
When do you move on to a new aligner if yours is stained?
In clear aligner treatment, how long each aligner is worn is determined by the treatment plan. Even if your aligner has turned yellow or stained, do not move on to the next aligner ahead of schedule on your own. Switching early can mean the teeth do not complete the planned movement and the new aligner does not fit. If the staining is noticeable, there is a bad smell or you notice a crack in the aligner, let the clinic know; the dentist decides whether a replacement aligner or a new scan is needed. For the general change routine, see our article how often are clear aligners changed?
How do you protect your aligner when you are out?
Keeping up a cleaning routine at work, at school or while travelling can be harder. Carrying an aligner case, a small toothbrush, travel-size toothpaste and a bottle of water makes things easier. When you cannot brush, at least rinse your mouth and the aligner well with water before putting it back in. When you take the aligner out at a café or restaurant, put it in its case rather than wrapping it in a napkin; many aligners are forgotten and lost this way. Make it a habit to clean the aligner more carefully when you get home in the evening.
Can the teeth discolour too?
When coloured drinks are consumed with the aligner in, the liquid can stay between the aligner and the tooth for a long time. This can lead to staining on the tooth surface and an increased risk of decay. For questions about tooth colour after treatment, take a look at our orthodontics and whitening page.
Frequently asked questions
Can I clean my aligner with boiling water?
No. Hot water can distort the aligner's shape and stop it fitting on the teeth. Use cold or lukewarm water.
Can I drink unsweetened tea with the aligner in?
Even without sugar, tea can cause staining. It is recommended to drink only plain water while the aligner is in your mouth.
Does a yellowed aligner affect the treatment?
Discolouration on its own does not always affect how the aligner works; however, if there is a crack, distortion or a fit problem, let the clinic know.
How can you find out what suits you?
The information here is general; the right plan for you is determined through an examination and the dentist's assessment. At our clinic in Oran, Çankaya, Ankara, we discuss your questions with you during the first orthodontic examination.
