Cleaning Invisalign® aligners – Making the case that brushing alone makes a good choice.
Once you’ve begun your Invisalign® treatment, you’ll no doubt be interested in knowing what it will take to keep your aligners clean, clear and odor-free.
Brushing is the key.
As it turns out, research suggests that mechanical cleansing (like brushing) seems to be the most important part of aligner home care. And in fact, based on study findings it’s easy enough to make the case that for most people just brushing alone usually makes a satisfactory cleaning method.
(That’s in contrast to just soaking aligners. We’re unaware of any research that has suggested that the use of a soaking solution alone is effective.)
What this page covers.
Towards helping you understand what you need to do in terms of aligner care, this page explains:
- What research studies have found about the effectiveness of aligner brushing vs. other cleaning methods.
- Also based on research findings, why how you brush (cleanser used, brush characteristics, brushing method, etc …) actually does need to be considered.
- How the use of an ultrasonic cleaning unit can improve your effort’s effectiveness.
- Should soaking your aligners be a part of your home care routine?
Beyond that …
We have two companion pages to this one that explain other aspects of cleaning aligners.
- One focuses on the importance of using the Invisalign’s® Cleaning System (Cleaning Crystals) Must you use it?, as documented by research studies.
- The other discusses findings from research that pertain to alternatives to the use of Invisalign’s® crystals. Possible options.
An Invisalign® aligner.
Why is brushing so important in cleaning your Invisalign® aligners?
Findings from research.
As we were collecting information for this page, it didn’t take long for us to notice that essentially every study we read that had included aligner/retainer brushing as a cleaning method reported that it alone generally produced effective results. Here are some examples:
(Note: Aligners and retainers are essentially identical objects, and therefore involve the same cleaning issues.)
More about cleaning Invisalign®.
Study #1 – Levrini
This study included brushing aligners with toothpaste as one of the cleaning methods it evaluated and stated that – “Simple brushing with toothpaste nevertheless gave excellent results.”
Study #2 – Levrini
Title: ATP Bioluminometers Analysis on the Surfaces of Removable Orthodontic Aligners after the Use of Different Cleaning Methods.
This study also included just brushing as one of the cleaning methods it evaluated. The paper states in its conclusions – “The mechanical removal of the bacterial biofilm proved to be effective with brushing and toothpaste.”
Study #3 – Albanna
Title: Microbial evaluation of the effectiveness of different methods for cleansing clear orthodontic retainers: A randomized clinical trial.
The discussion section of this paper states – “This study shows that brushing retainers is an effective cleaning method.”
Study #4 – Chang
Title: An assessment of the effectiveness of mechanical and chemical cleaning of Essix orthodontic retainer.
This paper’s conclusions state – “All three cleaning methods effectively removed 99% of microorganisms from the Essix retainers. Brushing with fluoride toothpaste can, therefore, be confirmed as an effective method for cleaning retainers in most circumstances.”
What does Invisalign® formally say about aligner cleaning?
The FAQ page on Invisalign.com states (06/22/2019):
- “The best way to clean your aligners is to use the Invisalign Cleaning System” … (continued sales pitch).
- “You can also brush them with a toothbrush and toothpaste and rinse them in lukewarm water.”
We’re unclear about what data this first statement is based on.
The second statement confirms brushing as a cleaning method.
Of course, we took note of the fact that Invisalign’s® FAQs do recognize brushing as an appropriate way to clean their appliances. (A method that a number of studies have shown is effective.)
Brushing your aligners is cheap.
Just as a side note, we’ll point out that brushing your aligners happens to be a very inexpensive cleaning method.
Whereas the cost of Invisalign’s® Cleaning Crystals runs on the order of a dollar per single-use packet, a routine of brushing your aligners costs just a small fraction of that amount.
Issues associated with aligner brushing.
Just as the use of different soaking solutions can have a detrimental effect on the physical properties of aligners The concerns., you might be surprised to learn that studies have shown that brushing them can too.
Admittedly, due to the short two-week duration aligners are usually worn for, the level of change/deterioration that occurs can be expected to be inconsequential. But as a best practice, each of these issues should be kept in mind.
a) Aligner scratching.
As you brush, your actions will tend to scuff up and scratch the plastic surface of your aligners. As the number of minute scratches increases with each cleaning session, two possible issues may arise:
- Increased visibility – As an aligner’s surface accumulates scratch marks, it also looses some of its optical clarity. If enough scratches accumulate, your aligners may be more noticeable to others when you wear them.
- Greater biofilm accumulation – Scratched aligner surfaces provide more opportunity for microorganism colonization, thus making them more difficult to thoroughly clean.
Steps you need to take to minimize aligner scratching when brushing.
1) Use a soft toothbrush.
- Read the packaging of the toothbrushes you find available and choose one that’s labeled as having “soft” bristles.
- Before brushing your aligners, moisten your toothbrush’s bristles with water and flex them with your finger as a way of loosening them up.
2) Use a toothpaste that has low abrasiveness.
We were really surprised to find that many research studies, and even Invisalign’s® own website, discussed the use of toothpaste when brushing aligners.
A toothpaste’s formulation almost always includes some type of abrasive compound (especially whitening toothpastes).
To us, that type of product hardly seems the right choice for cleaning plastic surfaces.
A simple way to make our point about this concern is to take some examples from published papers:
- Studies by both Wible and Agarwal found that just brushing with water caused a reduction in the light transmittance (optical clarity) of the types of plastics Invisalign® aligners are made from (copolyester and polyurethane).
(These studies evaluated the effect of 48 two-minute brushings. Brushing 3 times a day over a 2 week wear period would create 42 exposures, practically the same number.)
- We couldn’t help but notice that in a pair of aligner brushing studies by Levrini that the first one involved the use of toothpastes that had a “relative dentin abrasion value of less than 150,” (which really includes most products). The second lowered that range to 100 and less.
The choice of 100-and-less products would help to minimize aligner scratching. But we don’t know if that was the reason for the change in these otherwise very similarly designed studies.
(FYI: This study lists toothpaste products according to their level of abrasiveness. Go to website. Look for the “click here to view” link.)
In regard to the issue of abrasiveness, it may be that while aligner scratching does occur, on a practical level it’s not generally a concern due to the short two-week time frame over which the sets of these appliances are usually worn.
We’re entirely content with this line of thought. But to us, it seems that instead of using toothpaste (which is designed with teeth in mind, not plastic surfaces), that using a mild dishwashing detergent solution makes a better choice.
More about the Invisalign® experience.
3) Consider using detergent as a cleanser.
The general recommendation is to mix the detergent with water to create a mild soap solution. (Create a concentration that makes suds but is easy to wash off too. Mix enough that you have it on hand ready to use.)
While we couldn’t find a study that had evaluated this cleaning option specifically with aligners, we did run across a paper that had addressed this subject in regard to cleaning dentures.
4) Use a dedicated toothbrush for cleaning your aligners.
It’s always best to set aside a toothbrush that you just use for cleaning your appliances.
- Even after rinsing, a toothbrush that has been used with toothpaste will still harbor some of its abrasive particles.
- Having a dedicated brush means that you can choose one that has a size or shape that is especially well suited for this purpose. As an example, you might find that a child-sized toothbrush or a narrow-headed adult one is needed to be able to reach into the deepest recesses of your aligners.
b) Don’t brush too hard.
While reading the Wible and Agarwal studies mentioned above, we were surprised to learn that just brushing with water was found to cause flexibility changes in the types of plastics that Invisalign® aligners are made out of (copolyester and polyurethane) after only 48 two-minute brushing sessions.
▲ Section references – Wible, Agarwal
c) Never rinse your aligners with hot water.
As plastic appliances, exposing your aligners to elevated temperatures has the potential to distort them. After brushing, rinse them in lukewarm to cool tap water.
For all extra-oral events, maintaining a lukewarm/room temperature environment for your aligners always makes the right choice.
Innovative devices and solutions for cleaning issues encountered by Invisalign® wearers.
d) Consider using an ultrasonic cleaning unit.
Ultrasonic baths have a long history of being used to clean oral appliances. And like brushing, they create a mechanical cleansing effect. (We discuss ultrasonic units in detail here. How they work. | Benefits.)
A study by Shpack evaluated the use of ultrasonic cleaners with Invisalign® aligners. Two of the study’s findings were:
- The use of Invisalign’s® Cleaning Crystals on their own was not found to be effective in cleansing aligners (15 minute soaking period with container shaking). Using the solution in combination with an ultrasonic unit was.
- The study also demonstrated that the use of an ultrasonic unit following brushing was substantially more effective than just brushing alone.
Discussion in this paper pointed out that brushing may fail to thoroughly clean deeply recessed portions of aligners, like where they cover over the biting edges of front teeth or Invisalign® attachments. What are these? (So when brushing, give extra attention to these kinds of areas.)
As a way of insuring better effectiveness, the conclusions of this paper stated that it “highly recommended” the use of a vibratory bath protocol.
Sonic cleaners vs. ultrasonic units.
We’ve noticed battery-operated vibrating baths for sale for use with aligners and retainers. These low-end, low-frequency devices don’t offer the same advantages as ultrasonic units and are not a substitute. (Here’s why: Sonic vs. ultrasonic cleaners. They’re not the same.)
e) Should you use a soaking solution with your aligners?
Our purpose in writing this page wasn’t to suggest that you shouldn’t use a soaking solution with your aligners but instead to relay that you shouldn’t rely on that cleaning method alone.
We don’t think that most people understand that the most significant aspect of aligner cleaning is accomplished by mechanical cleansing. That it alone typically is satisfactory on its own. And that the use of a soaking solution is best considered an adjunct (like for intermittent use).
We’ve created additional pages that discuss the use of soaking solutions in greater detail. They are:
- How important is it to use Invisalign’s® Cleaning System / Cleaning Crystals? What do studies document?
- Possible alternatives to the use of Invisalign’s® crystals. Homemade and commercial.
Page references sources:
Agarwal M, et al. Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material.
Albanna RH, et al. Microbial evaluation of the effectiveness of different methods for cleansing clear orthodontic retainers: A randomized clinical trial.
Chang CS, et al. An assessment of the effectiveness of mechanical and chemical cleaning of Essix orthodontic retainer.
Invisalign.com Frequently Asked Questions.
Levrini L, et al. ATP Bioluminometers Analysis on the Surfaces of Removable Orthodontic Aligners after the Use of Different Cleaning Methods.
Levrini L, et al. Scanning electron microscopy analysis of the growth of dental plaque on the surfaces of removable orthodontic aligners after the use of different cleaning methods.
Rathee M, et al. Denture Hygiene in Geriatric Persons.
Shpack N, et al. Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance.
Wible E, et al. Long-term effects of different cleaning methods on copolyester retainer properties.
All reference sources for topic Straightening Teeth.