UV denture cleaning units (sanitizers) -

How do they work?  |  How effective are they? - a) denture sanitizing vs. disinfection vs. sterilization,  b) as compared to other methods  c) what does dental research say?  |  Combination units - ultraviolet light/vibratory bath (sonic, ultrasonic) denture cleaners.

You may have noticed UV denture sanitizers for sale and wondered if these devices offer an effective way to clean false teeth.

We had a website visitor who posed this same question to us. So we did some research and as a result have created this page. It tries to answer this question objectively (based on scientific evidence). Then afterward, we add our own two cents on this matter.

Additional product selections are shown at the bottom of this page.

Does UV light disinfection really work?

Yes, there is no question that ultraviolet (UV) light does have the ability to kill microorganisms. As an example, it's been used as a method of water disinfection for over 100 years. (Here's how it works.)

How effective are UV denture cleaners?

The aim of using one of these units is to help to reduce bacterial, yeast (fungal), and viral counts on either complete or partial dentures.

But before we say more than just that, there are some terms that need to be defined first. They are:

Sterilization vs. Disinfection vs. Sanitizing

Generally speaking, there are three levels of cleansing that at-home denture cleaning might be able to achieve. The terms used for each of them are: sterilization, disinfection and sanitization. Here's what each means:

  • Sterilization is the situation where the process used (exposure to UV light in this case) has killed 100% of the live microorganisms on the denture. And while it's possible that this level of cleansing may have taken place, it's not the norm.
  • The term disinfection refers to the case where the number of microorganisms present has been significantly reduced, but some (small) level of live organisms still remain on the appliance.

    This is probably the best case scenario for at-home denture cleaning. But how closely a person comes to actually achieving this state would be very dependent on the precise protocol they've used. (Both the effectiveness of their method and the manner in which it was carried out).

  • Sanitizing simply refers to a process where the level of microorganisms present has been reduced to non-threatening levels.

    With most at-home efforts, we'd expect that this is the highest level of denture cleaning that is achieved. And in fact when you look at the UV denture units for sale, they're typically labeled as denture sanitizers or even just cleaners, as opposed to sterilizers or disinfection units.

 

What level of sanitizing is possible with UV cleaning?

Before we discuss research studies that specifically investigated sanitizing dentures using UV light, we think it's valuable to mention some related dental research about ultraviolet cleaning in general. We'll mention why in our discussion.

Toothbrush studies.

We found a study (Berger 2008) [page references] that evaluated the effectiveness of two at-home UV toothbrush sanitizers.

Now clearly a toothbrush is a different type of object than a denture. But the types of microorganisms harbored on both should be at least similar.

The study found that:

  • One unit reduced the level of (gram-negative and gram-positive) bacteria 100% of the time it was used, while the lesser one 83% of the time.
  • And 83% of the time the better unit was used, it produced results that actually did achieve a high level of sanitization.

That suggests that UV sanitizers can be effective in controlling microorganisms (bacteria in this case) whose source is the mouth.

Cleaning other dental/oral objects.

Covering a broader range of objects, a paper by Yildirim-Bicer (2014) cites several studies that found UV sanitizing to be an effective means for reducing levels of oral fungi and bacteria on dental impressions, handpieces (drills) and tooth implants (artificial replacements for teeth).

So clearly the subject of UV disinfection of objects harboring microorganisms originating from the mouth offers some merit.

Studies investigating the use of UV light in cleaning dentures.

Our search of published dental research only found two relatively recent studies that had investigated the use of UV sanitizers with dentures. Both investigations compared using these types of units to other commonly used cleaning methods.

Using Candida albicans as the test microorganism.

In comparison to the two studies mentioned above that investigated the effectiveness of UV light with bacteria, the denture studies we found focused solely on the reduction of Candida albicans, a common oral fungus.

And while you may not be all that familiar with it, it's easy enough to make the case that this microorganism is the one of greatest concern in regard to denture cleaning.

  • Ribeiro (2012) found higher levels of Candida albicans on full dentures than the bacteria Streptococcus mutans or Staphylococcus aureus (strains of common oral bacteria).
  • Candida is a known cause of denture stomatitis (inflammation of the gum tissue a denture rests on). It's estimated that 60% of wearers suffer from this problem. (Yildirim-Bicer 2014)

The studies:

The facts.

At face value you'll see that the following denture disinfection studies don't really support the notion of ultraviolet light denture cleaning, at least by itself.

Our conjecture.

But when you consider how UV cleansing might be used in conjunction with other methods, then it seems likely that using one of these units could add value to your efforts. We discuss this position lower down on this page.

Study #1 - Lee (2011)

For this study:

  • The researchers made rectangles of denture acrylic (the plastic used to make the pink portion of a denture) ...
  • The samples were then contaminated with cultures of Candida albicans (the common oral fungus mentioned above) ...
  • The samples were then exposed to ultraviolet light for 10 minutes on each side.
Comparison methods.

Other acrylic samples were cleansed using traditional denture cleaning methods:

Study findings.
  • Out of the four techniques, the combination method (brushing and soaking) proved to be the most effective. It was able to make a significant reduction in the level of Candida albicans present on the test pieces.
  • It was determined that just brushing-and-rinsing or else using a commercial soak alone were each also more effective than the use of a UV sanitizer.

Study #2 - Yildirim-Bicer (2014)

This study evaluated the comparative effectiveness of different denture cleansing protocols, one of which involved the use of a UV denture sanitizer (20 minute exposure).

  • Samples of acrylic (pink denture plastic) were contaminated with strains of Candida albicans (the common oral fungus mentioned above).
  • The other cleaning methods evaluated by the study included three homemade soaks (1% diluted bleach solution, 50% and 100% vinegar solution) and one commercial soak (a product similar to the effervescent tablet used in the Lee study).

The findings of the study were that:

  • The vinegar and commercial soaks consistently achieved more effective disinfection of Candida albicans from the plastic samples than the UV method.
  • In most test situations, so did the 1% bleach solution.
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Some thoughts about these findings.

At face value, the conclusions of both of these studies suggest that you'd be better off spending your money on other methods of denture cleaning rather than UV sanitization.

Rebuttal.

In defense of UV units we think it's appropriate to point out the following points. Admittedly however, these are just our conjecture. We have no scientific evidence (no study to cite) that directly supports these statements.

a) Consider the use of a UV unit as an adjunct.

One thing neither of the studies above did was to investigate the effectiveness of UV denture cleaning as an aid to other methods.

As a specific example, the Lee (2011) study mentioned above determined that a brushing-and-rinsing protocol was more effective than using a UV sanitizer on it's own.

  • But it seems simple enough to anticipate that brushing, rinsing and then making use of UV disinfection would reach a higher level of cleanliness than just brushing and rinsing alone (which is known to leave microorganisms behind).
  • Generally speaking, brushing first is always a good idea and helps to enhance denture cleaning. In the case of UV sanitizing, it's easy enough to imagine how doing so would remove bulk debris and break up accumulation that would otherwise shield microorganisms from exposure to the light.

    To us it seems unfair to not have evaluated a brushing-first UV protocol as at least one of the test variants in this study.

b) Many ultraviolet units also feature a vibratory bath.

A common design for UV denture cleaners is one where the unit also features a sonic, or preferably ultrasonic, vibratory bath. Having this design means that two different denture cleaning methods are performed simultaneously.

As a difficulty in providing (accurate, valid) information about these types of dual units, we must simply state that we are unaware of any published research that has tested and reported about the possible increased level of effectiveness achieved when these two methods are used in conjunction.

Not everything that seems logical turns out to be accurate. But especially in the case where a person was otherwise already planning to take advantage of ultrasonic denture cleaning, we fail to see how buying a unit that also has UV capabilities would not make a reasonable, or even preferred, choice.


Additional points about using UV denture cleaning units.

a) Additional advantages of using this method.

The fact that ultraviolet sanitization doesn't require the use of chemicals or heat is favorable for the process of denture cleaning. It avoids the following issues:

  • No chemicals are involved that might damage the denture's plastic or place the denture wearer at risk (tissue irritation, allergic reaction or other health-related concerns).
  • Dentures are plastic objects. If exposed to elevated temperatures they may warp.

b) Possible concerns with UV units with baths.

UV denture cleaning units often have a design that includes a vibratory (sonic or ultrasonic) bath. (This allows two cleaning methods to occur simultaneously. See text and link above for more information.)

Some manufacturers warn that daily treatment of pairs of dentures together (two appliances) may result in wear as they vibrate against each other. Separate treatment for each individual appliance is recommended.

c) Using a UV wand for denture sanitizing.

The idea of writing this page came from a visitor's feedback that inquired about the use of wand-style UV sanitizers for denture cleaning.

i) UV light levels.

We're not in a position to know how the level of ultraviolet light output by a hand held wand sanitizer compares to units specifically designed for cleaning dentures. It's easy enough however to assume that a wand might be used effectively.

The main difference that comes to mind for us centers around the issue of how convenient it might be to use this type of device.

  • Since it's the light itself that produces the disinfection effect, all sides of a denture must be treated. At minimum, a denture would have at least two sides requiring exposure.
  • Per our Lee (2011) reference above, an exposure time on the order of 10 minutes per side is needed.

The above means that when using a wand sanitizer, the person must be willing to take the time to manually hold their device for a period of at least 20 minutes, and flip their denture(s) over at the half-way point.

All portions of each denture would need to be fully irradiated. When treating large or multiple appliances it seems that a wand would need to be moved around so all surfaces receive a full-strength exposure. If so, a longer treatment period would be needed to accomplish this task.

ii) Risks / Concerns when using a UV wand.

Repeated exposure of a person's skin to ultraviolet light creates a cancer risk. That means a person should not hold their dentures during the sanitization process.

Dedicated denture cleaning units sidestep this issue because their UV light only comes on once the lid of the device has been closed.


How does UV sanitizing work?

The mechanism on which UV light disinfection is based has to do with a phenomenon where (short wavelength) ultraviolet light damages the DNA of exposed microorganisms. This damage disrupts their ability to perform vital cellular functions. And as a result, the organisms die.

Just like you'd expect, the light physically has to land on the microorganisms to be effective. That makes purifying things like water relatively straightforward, in the sense that the light can fully penetrate throughout the solution being treated.

How does denture cleaning with UV light work?

The same disinfection process just described takes place with dentures too. However there are some issues that must be kept in mind.

Since dentures are opaque objects (light can't pass through them), the level of sterilization, disinfection or sanitization that's possible will correlate with the degree to which the microorganisms are exposed to the light treatment.

  • At minimum, both "sides" of a denture must receive an exposure.

    The treatment chamber of a denture cleaning unit is typically designed with more than one light source (bulb), or else the output from a single source is reflected about, thus adequately irradiating all of the appliance's surfaces.

  • Microorganisms that live in clumps of debris on a denture's surface may not receive an adequate exposure.

    That's why a denture should always be brushed prior to being placed in a UV cleaning unit. (This isn't unique to just UV disinfection. The effectiveness of all denture cleaning methods benefit from this step.)

 

 
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