is my fresh breath going to kill me?

October 7, 2007 11:03 AM

BadBreathFilter: By using mouthwash on an irregular basis, am I actually strengthening the bacteria in my mouth?

If I understood my Biology teacher correctly, when prescribed antibiotics, one needs to take the entire prescription, to ensure that all the bacteria is killed. This is because any surviving bacteria will become stronger and more resistant to the antibiotics, and the next time you get sick, a stronger dose wll be needed.

Well, if some mouthwashes contain anti-bacterial agents, am I not strengthening the bacteria in my mouth by using them, especially if I use them on an irregular basis?

Or does the fact that we secrete saliva in the mouth physically remove the bacteria, therefore there is no need to worry about any resistant bacteria in the mouth?

posted by bitteroldman to health & fitness (18 answers total)

Depends on the anti-bacterial I think. Antibiotics are relatively easy to become resistant too, whereas incineration is damn near impossible to become resistant too. You might want to give the ingredients of your mouthwash, but I think it's going to be at the "by the time bacteria are resistant to this, we've got bigger problems" end of the spectrum.
posted by fvw at 12:03 PM on October 7, 2007

Listerine's antibacterial/microbial properties come from the alcohol in it, not any weak antibiotic meds. It works by lysing (destroying) the cell walls of the microbes in a fundamental way that does not allow for evolution to counteract it. Here I get sketchy, since biology was a long time ago, but I think bacteria developing a resistance to cell lysing is like expecting humans to develop a resistance to fire.
posted by schroedinger at 12:06 PM on October 7, 2007 [5 favorites]

If you insist on using mouthwash, get the alcohol-based ones and avoid the ones with specific anti-bacterial agents. Just don't swallow the alcohol -- it is usually methanol which is very toxic, unlike drinkable ethanol.

The thing is though that mouthwash is pointless. As soon as you lick your lips, burp, swallow some snot that dribbles down the back of your nose or put your finger in your mouth, you've reintroduced bacteria that will multiply like Noah's children in the warm, moist environment.

The best way to avoid bad breath is to brush and floss regularly and properly. Brush thoroughly but GENTLY, so as not to wear down the tooth enamel.
posted by randomstriker at 12:09 PM on October 7, 2007 [1 favorite]

Oh and the point of brushing/flossing is not to remove bacteria (though that helps), but to remove the residual food that bacteria feed on. A nutrient-poor environment is, effectively, a sterile environment.
posted by randomstriker at 12:27 PM on October 7, 2007 [2 favorites]

Scroedinger is right. The alcohol in mouthwash denatures proteins and lyses bacterial cells. This can't be defended against in any simple way, like circumventing a certain biochemical pathway, in the case of antibiotics.

That's not to say that all microorganisms are completely vulnerable to alcohol. Some critters that have a spore stage are well-defended from things like alcohol and extreme temperatures. Don't worry too much about that, though. Alcohol does a good job, and mouthwash is still a good idea.
posted by chrisamiller at 12:41 PM on October 7, 2007 [1 favorite]

Mouthwash is bactericidal - the bacteria can't evolve resistance to it.

That said, saliva contains antibodies that are meant to bathe your teeth and gums, protecting them from bacteria. Alcohol-based mouthwashes destroy these antibodies and cause tissue damage to your gums and oral mucosa by dehydrating and damaging cells, probably negating any benefical effect of using them to kill bacteria.
posted by ikkyu2 at 1:04 PM on October 7, 2007 [2 favorites]

Alcohol-based mouthwashes destroy these antibodies and cause tissue damage to your gums and oral mucosa by dehydrating and damaging cells, probably negating any benefical effect of using them to kill bacteria.

What should be used instead?
posted by tracert at 1:16 PM on October 7, 2007

Brushing and flossing.
posted by Justinian at 1:29 PM on October 7, 2007

Brushing and flossing.

And make sure you brush your tongue thoroughly as well.
posted by 6550 at 2:17 PM on October 7, 2007

Wow, this is great information! Thanks for all your help everyone!
posted by bitteroldman at 4:02 PM on October 7, 2007

.. meant to say, this is ALL great information!
posted by bitteroldman at 4:03 PM on October 7, 2007

Yeah, 6550 made a good point; brush your tongue as well.
posted by Justinian at 4:58 PM on October 7, 2007

Some students did some research on this a while ago: "the purpose of this study was to determine if the frequent use of mouthwash promotes antibacterial resistance" and the conclusion seems to have been "well, maybe".
posted by dreamyshade at 7:51 PM on October 7, 2007

That said, saliva contains antibodies that are meant to bathe your teeth and gums, protecting them from bacteria. Alcohol-based mouthwashes destroy these antibodies and cause tissue damage to your gums and oral mucosa by dehydrating and damaging cells, probably negating any benefical effect of using them to kill bacteria.

Any citations to support this? The ADA certainly disagrees with your claim, and I couldn't find anything to back you up with a cursory search of Pubmed.
posted by Thoughtcrime at 9:43 PM on October 7, 2007

"Rinses are generally classified by the U.S. Food and Drug Administration (FDA) as either cosmetic or therapeutic, or a combination of the two. Cosmetic rinses are commercial over-the-counter (OTC) products that help remove oral debris before or after brushing, temporarily suppress bad breath, diminish bacteria in the mouth and refresh the mouth with a pleasant taste. Therapeutic rinses have the benefits of their cosmetic counterparts, but also contain an added active ingredient that helps protect against some oral diseases. Therapeutic rinses are regulated by the FDA and are voluntarily approved by the American Dental Association (ADA).

Rinses are not considered substitutes for regular dental examinations and proper home care. Dentists stress a regimen of brushing with a fluoride toothpaste followed by flossing, twice a day. If done consistently and properly, the brushing and flossing, along with routine trips to the dentist, should be sufficient in fighting), tooth decay and periodontal disease."

I'm not sure that the ADA disagrees with Ikkyu's point, unless dentists are generally at odds with the ADA over the effectivness of mouthwash.
posted by oneirodynia at 11:25 PM on October 7, 2007

Ikkyu is claiming that mouthwash is bad for one's teeth and gums, so yes, the ADA disagrees with his point.

I'm aware that saliva does indeed contain antibodies, but not all proteins are denatured by alcohol. Hell, IgA (one of the salivary antibodies) can survive the low pH of the stomach, so would a mild amount of alcohol do anything to it?

The claim that mouthwash dehydrates the mouth seems fishy, too, since there really isn't all that much alcohol in most mouthwashes, and one's salivary glands quickly secrete more saliva into the mouth after rinsing. Even if it does dehydrate the mouth, will that actually cause tissue damage?
posted by Thoughtcrime at 12:34 PM on October 8, 2007

I like Biotene - it does not contain alcohol so it doesn't sting or let your mouth feel dried out.
posted by IndigoRain at 6:55 PM on October 8, 2007

I use Listerine, so I can't claim that I think it's terrible for you. I use it to reset my oral flora and because I like the way it tastes. "Therapeutic" mouthwashes almost all contain chlorhexidine, which I believe requires a prescription.

I wouldn't pay too much attention to the ADA's pronouncements without taking a careful look at how much money Warner-Lambert and Proctor and Gamble gives to it every year in return for being able to put 'ADA-approved' labels on their products. Hundreds of millions of dollars is something I think of as likely to generate conflict of interest.
posted by ikkyu2 at 11:27 AM on October 9, 2007