Chlorhexidine is the generic version of Peridex, a medicated mouth rinse that is often prescribed by dentists to treat various oral conditions. It's full name on the label is chlorhexidine gluconate 0.12% oral rinse (CHX) and is a cationic bis-biguanide.
This medicated mouth rinse is extremely effective in reducing plaque due to its antibacterial properties. However your dentist will usually only tell you to use it for 1-2 weeks at most because of it can stain your teeth.
Does it really stain your teeth and why does it happen?
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Can chlorhexidine stain your teeth?
It has been scientifically proven that chlorhexidine can stain your teeth. The longer you use it the more severe the stains will be which is why it is only used short term such as 2 weeks.
According to a systematic review in the Journal of Periodontology, there was a significant increase in staining when used. That was the bad news but the good news was that it significantly reduced plaque and gingivitis.
Those findings were consistent with other studies, which all found increases in staining and decreases in plaque from using it. That simply means that while it is an effective antibacterial mouth rinse, it comes with an undesired side effect. Short term use does not elicit this effect but long term use can discolor your pearly white teeth.
According to a Cochrane review, there was high quality evidence of significant plaque reduction when used. It seems to be very effective against mild gingivitis but not so much for severe forms of it.
Color of chlorhexidine stains
Frequent long term use of chlorhexidine will produce a brown colored stain. Even the label of this rinse warns you of this common adverse effect.
What chlorhexidine can stain:
Teeth (enamel and dentin surfaces).
Restorative materials in the mouth.
Dorsum of the tongue.
Supragingival calculus on teeth.
Based on what this mouth rinse can stain, it seems like everything that is present in the mouth is fair game. It's quite interesting that it can even discolor the tongue by turning it black and brown.
Does the concentration affect the amount of staining?
Interestingly enough, it appears that the concentration of chlorhexidine does have an effect on the quantity of teeth staining. The higher the concentration, the greater the staining potential. The vice versa is true in that the lower it is, the less stains there will be.
This was verified in a study which compared three different concentrations of the mouthwash, 0.2%, 0.12%, and 0.10%. As expected, the 0.10% solution had the least amount of staining. However the plaque reduction efficacy also decreased along with the amount of staining.
Unfortunately the antibacterial and staining potency seems to be concentration related. That's probably why this mouth rinse is only prescribed when needed and not used as an everyday mouthwash.
What about adding anti-discoloration systems to the rinse?
Some researchers have even tried adding ingredients which would prevent staining into the chlorhexidine formulation. Unfortunately the results of the study indicated there was no significant decrease in staining from it.
While efforts to improve the product may have failed, it doesn't mean that the community won't stop trying. Perhaps one day, someone will figure out a way to get rid of the CHX stains with some type of miraculous ingredient.
How does chlorhexidine cause staining?
Rinsing with chlorhexidine does not directly cause your teeth to stain. However it does seem to have a strong attraction to staining foods that may be present in your mouth.
Essentially when you rinse with chlorhexidine gluconate it will form a coating over your teeth. This coating very strongly attracts and retains stains on your teeth like a magnet. As an example, your teeth will stain X amount if you drink coffee but if you've been rinsing with it, the staining will be more than X.
This was demonstrated in a study which tested the amount of dye staining on teeth with and without a chlorhexidine coating. Of course, the teeth with it had dyes that were bound much more strongly to the teeth. The teeth without it did not retain as much staining.
The proposed mechanism for why that happened is due to the fact that chlorhexidine is positively charged while the dyes were negative. The opposite charges were strongly attracted to one another, thus resulting in teeth staining.
This was further validated in another study which also found strong evidence of interactions between dietary chromogens and locally adsorbed chlorhexidine. The teeth staining were due to staining chromogens that were interacting with the CHX that were coating it.
What makes the staining even worse is that the rinse increases tartar formation which tends to acquire stains more easily.
Are chlorhexidine stains permanent?
Chlorhexidine stains are not permanent because they can be removed by your dentist or with whitening toothpaste at home.
As per the instructions above, your dental cleaning appointment require more time in order to get the stains from chlorhexidine off of your teeth. Nonetheless, it is good news that the of tooth stains this medicated rinse produces is only temporary.
How do you get rid of the staining?
Teeth staining from chlorhexidine mouth rinse is of extrinsic origins, which means it can be removed mechanically.
Extrinsic means that it is located on the exterior of your tooth surface.
Mechanical removal means physically removing it from your enamel.
Treatment options via mechanical stain removal:
Professional dental cleaning. Your dentist will physically scale the stains off of your enamel with a teeth cleaning. Afterwards they'll polish your teeth with prophy paste.
Whitening toothpaste with abrasives. Any toothpaste that is labeled as whitening will contain abrasives in them. The grittiness of the abrasives will help you brush the stains off of your teeth. That is essentially how most whitening toothpastes work.
Alternatively, you can also remove the stains by chemically bleaching the teeth. All of these products contain peroxide in them, which can oxidize all of the stains.
Whitening strips
Whitening pens
Whitening trays
Any of these methods will work, just be aware that the OTC options cost less than the in-office ones with your dentist. Of course, the professionally done ones are much more potent and effective which is why they cost more.
What if I leave the staining as is?
You may be wondering if it was okay to leave the staining without removing it. Technically, teeth staining in general is purely cosmetic in nature and does not affect the function of your teeth. You'll still be able to chew, eat, and speak just fine with discolored teeth because yellow teeth are still considered healthy.
If you needed reassurance, the FDA explicitly states that the stain as a result of chlorhexidine does not adversely affect health of the gums or teeth. In other words, nothing bad will happen to your teeth because of the discoloration, it just won't look aesthetically pleasing.
Is it still worthwhile to use it?
Despite the unwanted cosmetic effect on your teeth, CHX is very effective at what it was meant to be, an antibacterial mouth rinse. All studies have pointed towards the fact that there was very strong evidence of its antibacterial properties.
It will significantly reduce plaque accumulation and control mild gum disease. That is the reason why your dentist will sometimes prescribe it for you after you've had a deep cleaning. They'll also give it to you if you've had a gum abscess or any type of gum swelling.
It works extremely well in killing all of the bacterial and getting your gums healthy faster. For that reason alone, we do think it is worthwhile to use it if you need it despite it not being a whitening mouthwash.
However, we wouldn't use it as our daily mouthwash because it can be very staining. On a day to day basis where you don't need its potent bactericidal effects, you can use a normal mouth rinse like Listerine instead. You can just save this medicated mouth rinse for a rainy day for when you truly need it.
