Alternative soaking solutions for cleaning Invisalign® aligners

- Findings from research about what alternative chemical cleansing options seem reasonable. | Invisalign® Cleaning Crystals vs. Retainer Brite® / Polident® / Mouthwash / Homemade cleaners - bleach, vinegar, peroxide.

Are there alternatives to using Invisalign's® Cleaning Crystals?

When you begin your Invisalign® treatment, your dentist will no doubt tell you about the Invisalign® Cleaning System. And you may wonder if there are any alternatives to using this specific product. Possibly one that's a little less pricey.

What we found.

While accumulating information for this page, it soon became apparent that there's no shortage of suggestions for alternative cleaning methods.

  • Many of them involve the use of agents that are frequently recommended for use with other types of removable dental appliances. (Bleach, vinegar, peroxide, denture cleaners, retainer cleansers, mouthwash, etc...)

    (By the way, not all of these options make a good choice, especially for use with aligners.)

  • Many of the recommendations we found were posted on the websites of what are apparently Invisalign® treatment providers. So we have little question that they are used.

 

We'd prefer to rely on research findings.

When investigating this issue from the scientific side, we were able to locate several published studies that had evaluated this subject (both specifically and tangentially) and were surprised to discover what a complex subject this can be.

What studies report.

As it turns out, there are apparently no perfectly ideal cleaning methods for the types of plastics Invisalign® layers together to make their aligners. (This even includes the use of Invisalign's® own Cleaning Crystals.)

  • The use of all cleaning methods tends to degrade the optical clarity of these plastics over time. (An issue that can affect how noticeable your aligners are when worn.)
  • The use of some alternative cleaning methods has the potential to affect aligner surface roughness. (An issue associated with aligner visibility, and maintaining appliance hygiene.)
  • And concerns with changes in aligner flexibility exist with some options. (A factor that could affect your aligner's ability to create tooth movements, and therefore affect your treatment's progress.)

 

Coming to a practical conclusion.

Even with the scientific information that's available, drawing conclusions is still difficult. For example:
  • Some published studies have investigated the use of alternative cleansers on polyurethane and copolyester plastics independently but not as a layered material composed of both. (Like the composition of the Smarttrack® material Invisalign® uses for aligners.)
  • Some of the studies' evaluations involve test periods that exceed what would be characteristic for normal aligner wear.

 

Our conjecture.

This last point may be the saving grace for cleaning methods in general. Each set of aligners is typically worn for just two weeks. And due to their limited exposure to cleaning agents over this time frame, we anticipate that whatever effects are possible typically remain inconsequential.

A plan.

We do think that in all cases you should get your dentist's OK on the method you choose. But beyond that ...
  • If the appearance of your aligners (their optical clarity) remains stable during the period while they're worn.
  • And aligner odor, staining and accumulation of debris is not a problem.
  • And you transition seamlessly between sets of appliances, on schedule. (Possibly a point your dentist should pass judgment on.)

... Then we're not sure what other factors would be a concern in regard to the effects of cleaning agents on aligners.

Do you really need to soak your aligners to clean them?

Of course, a quest for an alternative cleaning method implies a mindset that using Invisalign's® Cleaning Crystals is really necessary.

We don't entirely agree with this view. We discuss why on our "How important is it to use the Invisalign® Cleaning System?" page.


Alternative cleaning methods discussed on this page:

 

Additional factors in cleaning aligners.

You might be surprised to learn that mechanically cleansing your appliances (brushing or using an ultrasonic unit) plays a vital role in your being able to cleanse them effectively.

In fact, the use of any chemical cleanser (soaking solution) should always be accompanied by this step. In light of this point, we consider our discussion about how to mechanically cleanse (brush) your aligners a must-read.


Possible alternatives to using Invisalign's® Cleaning System / Cleaning Crystals.

Note: We'd anticipate that the information on this page is applicable to other brands of aligner systems too (ClearCorrect®, ClearPath®, eCligner®, Simpli 5®, etc... ). But the exact composition of the plastic used with each system varies, and therefore we don't know for certain.

Invisalign® aligners are made using their Smarttrack® material. This is a layered plastic composed of polyurethane and copolyester. These two types of plastic are the main focus of this page.

Note: Cleaners are for external use only.

It's important to keep in mind that soaking solutions are intended for external usage only (soaking your aligners in a container). Any residual liquid that remains on them after cleaning should be thoroughly rinsed off with lukewarm tap water before they are placed back into your mouth.

Note: Safety concerns about cleansers that contain persulfates.

Some commercial soaking preparations (denture/retainer/aligner cleaners) are formulated with what is generally referred to as persulfates and there can be safety issues associated with their use (see link above). For this reason, you should evaluate the packaging of the product you choose.

Commercially prepared cleansers -

1) Aligner / Retainer cleansers - like Retainer Brite®

There are several commercially prepared products whose packaging specifically states that they are suitable for use with clear orthodontic aligners (like Invisalign®). Some of the brand names we've noticed are Retainer Brite®, SonicBrite®, Dental Duty® and SmartGuard® but there are additional ones too.

  • These products typically claim to be effective in removing accumulated staining, and being able to kill bacteria and other microorganisms.
  • Ingredient information isn't always so easily found for these products.

    As a point of comparison, if you do find this information, Invisalign® Cleaning Crystals are composed of: Sodium sulfate (60%), sodium carbonate (30%), sodium tripolyphosphate
    (7.5%), sodium dichloroisocyanurate (2%), and sodium lauryl sulfate (0.15%).

    At this point in time, we're unaware of any alternative products that have a substantially similar formulation.

Section references - Shpack

A picture of an Invisalign® tooth aligner.

An Invisalign® aligner.

Example - Retainer Brite®.

While collecting information for this page, the only published research we found that included the use of this type of cleanser alternative had evaluated Retainer Brite's® product. So, the bulk of the information we have to share centers around its use.

Ingredients.

We were able to find the Materials Safety Data Sheet for Retainer Brite®. The active ingredients listed are potassium monopersulfate and sodium perborate monohydrate. That seems to make it more akin to the formulation of denture cleaners as opposed to Invsialign's® crystals.

Important: Safety concerns about cleansers that contain persulfates.

Research.

Study #1 - Albanna

Title: Microbial evaluation of the effectiveness of different methods for cleansing clear orthodontic retainers: A randomized clinical trial.

Background.

This study was designed to evaluate the added value of using a soaking agent (Retainer Brite®) after brushing dental appliances with a toothbrush and toothpaste.

Findings.

This paper reported that the use of the cleanser did not significantly reduce bacterial levels beyond what was accomplished via toothbrush and toothpaste alone.

And in fact, the paper specifically states: "This study shows that brushing retainers is an effective cleaning method." (Note, the cleaning challenges and needs of retainers and aligners are essentially identical.)

Points to consider.
  • Other than just Retainer Brite®, this study also evaluated the use of two other commercial soaks (neither of which are commonly sold in the USA). It was determined that these products also failed to provide an additional level of disinfection.

    As such, we're inclined to think that this study may be more of a testament to the effectiveness of brushing, as opposed to the ineffectiveness of the soaking products. (Formulating a cleanser that kills bacteria is hardly rocket science. How could three separate companies fail to do so?)

  • As a point of comparison, on our Invisalign® page we discuss that two studies conducted by Levrini did find that the added use of their Cleaning Crystals after brushing did further reduce bacterial counts.

    (FYI: These studies also stated that just brushing aligners with toothpaste gave excellent results.)

  • However, a study by Shpack states that it found the use of Invisalign's® crystals ineffective against the bacteria it tested for. So drawing conclusions about how the use of Retainer Bright® stacks up against Invisalign's® product in regard to disinfection is difficult to gauge.

Section references - Albanna, Levrini, Levrini, Shpack

Study #2 - Wible

Title: Long-term effects of different cleaning methods on copolyester retainer properties.

Background.

Beyond just effectiveness, the use of a cleaning product must not alter the appearance or other physical characteristics of an aligner. (We explain in greater detail here about what concerns there are.)

Findings.

In regard to having a minimal effect on aligner plastic (specifically copolyester, one of the types of materials used for Invisalign® appliances), this study found that after use over a 6-month period of twice-weekly use, the Invisalign® Cleaning Crystals and Retainer Brite® products both tested similarly.

Specifically, neither was found to significantly change the plastic's surface roughness or flexural modulus (a measure of flexibility). Both products caused a similar level of reduction in light transmittance (optical clarity).

Section references - Wible

Vibratory cleaning units.

We've noticed that some manufacturers that sell retainer cleansers also sell battery-powered vibrating baths. We discuss the merit of the use of sonic/ultrasonic cleaning units here.)


Pictures of aids used with Invisalign® cleaning.

Our affiliate links can be used to shop  Invisalign® cleaning products/units  on  Amazon.com  or  Walmart.com

Innovative devices and solutions for cleaning issues encountered by Invisalign® wearers.


▶ Our conclusions about the use of Retainer Brite® as an alternative to Invisalign's® Cleaning Crystals.

  • In terms of doing no physical harm to your aligners (at least in regard to the copolyester component), the fact that the use of both this product and Invisalign's® crystals tested similarly is positive.

    (We found no corresponding study about Retainer Brite's® effects on polyurethane plastic.)

  • In terms of cleansing effectiveness, in light of the findings of the studies discussed above it seems very difficult to formulate an opinion about the comparative effectiveness of Retainer Brite® (or similarly formulated product) vs. Invisalign's® Cleaning Crystals. (More to the point, it seems difficult to see the clear-cut benefit of using either.)

 

We'll also point out ...
  • What we really find noticeable about the Albanna and two Levrini studies is that they each suggest that just brushing your aligners probably makes a perfectly suitable alternative cleaning method on its own.
  • We'll also add that we are totally unaware of any research that suggests that the use of any type of soaking solution alone, without any mechanical cleansing (like brushing), is an effective cleaning method. In fact, the Shpack study mentioned above seems to have demonstrated this in regard to the use of Invisalign's® crystals.

 

2) Effervescent denture cleansing products - like Polident®

Background.
Commercially prepared effervescent denture cleaning products (tablets, powders, crystals and foams) are usually formulated with some type of oxidizing agent that is capable of killing microorganisms and removing stains.

Important: Safety concerns about cleansers that contain persulfates.

The research studies that we found that had investigated the use of denture cleaners with the types of plastics used to make Invisalign's® orthodontic aligners specifically evaluated Polident®, so that product is the focus of our discussion here. Of course, both proprietary and generic equivalents exist.

Illustration of cleaning removable orthodontic aligners in a commercial soaking solution.

Cleaning Invisalign® aligners with an effervescent soak.

Research.

Study #1 - Baba
Title: Effectiveness of a combination denture-cleaning method versus a mechanical method: comparison of denture cleanliness, patient satisfaction, and oral health-related quality of life.
Background.

This study is admittedly off-target to our topic, in the sense that it evaluated the added effectiveness of using Polident® soak with dentures (not aligners).

Findings.

The study found that a protocol that involved both brushing and using the soak was more effective in disinfecting appliances than just brushing alone.

  • We've mentioned this study to point out that the use of denture cleansers can be effective in sanitizing oral appliances.
  • And to suggest that it seems reasonable to assume that it would be similarly effective in disinfecting orthodontic aligners too. (Although we could find no study that had investigated this specific application.)

Section references - Baba, Levrini

Studies #2 and #3 - Wible, Agarwal

Title: Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material.

Title: Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material.

Background.

These studies evaluated the effect of denture cleaner (Polident®) on the physical characteristics/properties of polyurethane and copolyester plastics. (These plastics are layered together to make Invisalign's® Smarttrack aligner material.)

We think it's important to point out that these studies evaluated 6 months of twice-weekly use. That's a total of 48 exposures to the cleaning solution. In comparison, soaking aligners once daily over their common 2-week wear period would create 14 exposures.

Findings.

In some ways, the use of Polident® tested similarly to Invisalign's® Cleaning Crystals. Both resulted in some decrease in aligner optical clarity. But neither significantly altered the plastic samples' surface smoothness.

But different than with Invisalign's® product, Polident® was found to have an effect on the flexural modulus (a measure of flexibility) of copolyester plastic (but not polyurethane).

Section references - Wible, Agarwal

Is this effect a big deal?

This same issue also comes up with the homemade cleaning alternatives we discuss below, and it's hard to know how much of a concern it is.

It is true that a change in an aligner's flexural modulus (flexibility) can alter its effectiveness in the way it applies forces to your teeth. But ...

  • These studies evaluated soaking protocol over a longer time frame and a greater number of total exposures than would be common with a single set of Invisalign® aligners.

    And in the case where a person's primary method of cleaning is via brushing (it's pretty easy to make a case for using it alone), and a denture soak is only used infrequently as an adjunct (possibly twice weekly, thus creating less than one-tenth the studied exposure), one could speculate about what level of change actually takes place.

    Unfortunately, we found no research study that had evaluated the use of denture cleansers on aligner plastics under these minimal conditions.

  • We'll also mention that a "statistically significant" change identified by a study (meaning from a standpoint of probability that randomness is not responsible for the effect that's noticed) is not the same as stating that the level of change that occurs amounts to a significant treatment problem.

    For very minute changes, we're not entirely sure this could be quantified. Admittedly however, no change created by the cleaning solution would certainly be the ideal.

 

What causes the effect?

Per discussion in the Wible paper, a proposed culprit for the flexural modulus changes is the exposure of the plastic to free radicals released by oxidative agents in the cleaning solution.

If that's correct, then it seems this issue is one of cause and effect. Thus suggesting that intermittent use of the cleaning solution would be a way of curbing the potential for the effect.

▶ Our conclusions about the use of Polident® as an alternative to Invisalign's® Cleaning Crystals.

  • Based on the findings of the study mentioned above, it seems reasonable to presume that similar to the use of Invisalign's® crystals, the use of denture cleanser (Polident®) can be effective in disinfecting orthodontic aligners, if you feel you need an added effect beyond just brushing.

    (We're unaware of any study that has supported the use of a denture cleanser alone, without brushing, is an effective method for cleaning dental appliances.)

  • In the case of short-term (2-weeks) intermittent use as an adjunct to regular brushing, we'd anticipate that using this type of product would make a suitable alternative to using Invisalign's® crystals. Although doing so should be discussed with your dentist first.
  • But for longer-term or more-frequent use, other alternatives would seem to make the wiser choice.

 

 

3) Homemade soaking solutions - Bleach based.

Background.

Bleach-based soaking solutions have a history of being used with dental appliances. They're effective in killing microorganisms and removing staining (like that caused by exposure to coffee, tea and colas).

Research.

Background.

This type of solution is typically prepared by mixing 1 part common household bleach (5.25% sodium hypochlorite) with 10 parts room temperature tap water to create a roughly 0.5% sodium hypochlorite solution. (The specific concentration of bleach products varies, so you'll need to check the labeling of the one you use and make adjustments accordingly.)

Both the Wible and Agarwal studies mentioned above included a 0.6% sodium hypochlorite in their investigation of the effects of cleaning methods on copolyester and polyurethane plastic samples over a 6-month period of twice-weekly soaking. (These are the two types of plastics found in the combination material used to make Invisalign® aligners.)

Findings.
  • In regard to polyurethane, the Agarwal study found that like Invisalign® Cleaning Crystals, bleach-based soak did affect the plastic's transparency but did not affect its flexural modulus (flexibility).

    But in comparison to the use of Invisalign's® product, it was found to affect surface roughness.

  • In regard to copolyester, the Wible study found that like Invisalign® Cleaning Crystals, the soak did affect the plastic's transparency but did not affect its surface roughness.

    But in comparison to the use of Invisalign's® product, it was found to affect the plastic's flexural modulus (flexibility).

 

▶ Our conclusions about the use of a bleach-based soaking solution as an alternative to Invisalign's® Cleaning Crystals.

Generally speaking, it is known that some types of plastics can be affected by sodium hypochlorite (the active ingredient in bleach). (Evidently the studies above demonstrate that.) But this concern is typically associated with exposure to high concentration solutions for long durations.

Much like our discussion above, the infrequent use of a bleach-based soak as an adjunct to a regular routine of aligner brushing can probably be accommodated with limited concern. (Get your dentist's OK first.)

But for more frequent use or longer durations, other options would seem to make the more prudent choice.

4) Homemade soaking solutions - Vinegar based.

Background.

There's nothing new about the use of vinegar-based (acetic acid) soaking solutions to clean dental appliances. Its effective in killing microorganisms and removing tartar deposits (dental calculus).

Tartar accumulation.

Due to the short 2-week duration that aligners are usually worn for, tartar accumulation typically isn't much of a problem for most people. In cases where it is, improper brushing habits (brushing ineffectively, or not often enough) are usually the underlying cause.

Research.

Background.

Vinegar soaking solutions are usually prepared by mixing ordinary white table vinegar (5% acetic acid) 50:50 with room temperature tap water to make a 2.5% solution. The appliance is then soaked for 10 minutes.

Both the Wible and Agarwal studies mentioned above included a 2.5% vinegar-based soak in their investigation of the effects of cleaning methods on copolyester and polyurethane plastic samples over a 6-month period of twice-weekly soaking. (These are the two types of plastics found in the combination material used to make Invisalign® aligners.)

Findings.
  • The Agarwal study reported that the vinegar solution did affect the transparency but not surface roughness of polyurethane (similar results as with the use of Invisalign's® crystals).

    But different than with the use of Invisalign's® product, it also affected this plastic's flexural modulus (a measure of stiffness).

  • The same findings were reported in regard to copolyester plastic by the Wible study.

 

▶ Our conclusions about the use of vinegar-based soak as an alternative to Invisalign's® Cleaning Crystals.

Vinegar solution's effect on both types of plastic used in the fabrication of Invisalign® aligners makes it hard to suggest that it makes an appropriate substitution for any type of regular use.

An isolated application used as a means of softening up hard deposits (tartar) that can't otherwise be removed might be tolerated. (Get your dentist's OK.)

But there seems to be good reason to use this preparation with caution. And not under circumstances where extended time frames of use, or long soaking durations, are involved.

5) Homemade soaking solutions - Peroxide based.

Background.

Peroxide-based soak is another homemade alternative that has a history of use with dental appliances.

Research.

Both the Wible and Agarwal studies mentioned above included a 3% hydrogen peroxide-based soak in their investigation of the effects of cleaning methods on copolyester and polyurethane plastic samples over a 6-month period of twice-weekly soaking. (These are the two types of plastics found in the combination material used to make Invisalign® aligners.)

3% hydrogen peroxide is a common pre-mixed concentration sold in stores.

Findings.
  • The Agarwal study determined that the use of a 3% peroxide solution (similar to the use of Invisalign® Cleaning Crystals) did affect the transparency but not the surface roughness or flexural modulus (flexibility) of polyurethane.
  • The Wible study found that (similar to the use of Invisalign's crystals) peroxide soak did affect aligner clarity but not the surface roughness of copolyester.

    But different than with the use of the Invisalign® product, it also affected this plastic's flexural modulus (a measure of stiffness). And like above, the paper speculated that it was free radicals released by the breakdown of the hydrogen peroxide that caused this effect.

    Probably most notable about the paper is that in its conclusions section, the author specifically states that hydrogen peroxide is not recommended as a cleaning solution for copolyester plastics. (Admittedly however, under the longer-term conditions evaluated by the study.)

 

▶ Our conclusions about the use of peroxide-based soak as an alternative to Invisalign's® Cleaning Crystals.

Considering that the use of a peroxide soak has nothing special to offer over other cleaning methods, and in light of the negative statement found in the Wible study's conclusions, there seems little reason to consider this cleaning alternative for aligners.

6) Mouthwash - like Listerine®.

Background.

Discussion about the use of mouthwash products as a cleanser for dental appliances usually centers around antiseptic-type rinses because they're effective in killing microorganisms. (Many types of mouthwash don't.)

While many generic equivalents exist, the best-known brand name associated with this type of product is Listerine®.

Research.

Both the Wible and Agarwal studies mentioned above included Listerine® in their investigation of the effects of cleaning methods on copolyester and polyurethane plastic samples over a 6-month period of twice-weekly soaking. (These are the two types of plastics found in the combination material used to make Invisalign® aligners.)

Findings.

Most of the concerns associated with using Listerine® as a cleanser centered on it's effect on copolyester.

  • It was found to alter the plastic's translucency, surface roughness, and flexural modulus (flexibility).

    Discussion in the paper suggested that the high level of alcohol (ethanol) found in the formulation of antiseptic mouthwashes (frequently over 20%) might be the causative agent. It also mentioned that ethanol exposure tended to discolor copolyester materials.

  • At least in regard to orthodontic retainers (a similar type of plastic appliance but one that's worn for, and therefore subjected to cleaning for, a much longer time frame than aligners), the author of the study (Wible) specifically states that the use of Listerine® is not recommended as a cleaning solution.

Section references - Wible

▶ Our conclusions about the use of mouthwash like Listerine® as an alternative to Invisalign's® Cleaning Crystals.

In light of the issues discussed above, and the fact that better alternative candidates exist, there seems to be no reason to consider the use of antiseptic mouthwash (Listerine®) for cleaning Invisalign® orthodontic aligners.


As further reading on the subject of aligner cleaning ...

 

 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.

Align Technology, Inc. Material Safety Data Sheet - SmartTrack Aligner Material. 12/08/2015

Baba Y, et al. Effectiveness of a combination denture-cleaning method versus a mechanical method: comparison of denture cleanliness, patient satisfaction, and oral health-related quality of life.

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.

Retainer Brite. Material Safety Data Sheet - Retainer Brite. 10/01/2012

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.

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