Friday, September 9, 2011

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Chlorine in swimming pools and it's effect on teeth.


Is it possible that spending a lot of time in the swimming pool can stain your teeth or even slowly dissolve your teeth?

First, we take a look into two different questions that many swimmers have regarding their teeth:

1. Can swimming pools stain my teeth?
2. Can swimming pools dissolve my teeth?

Can Swimming Pools Stain Your Teeth?

An interesting discussion on this topic came up in a thread on the U.S. Masters Swimming Forum.  The user ensignada led off with the following question:
I took my 8 year old to the dentist today for a check-up. One of our concerns was the brown discoloration on her two front teeth. The first question the dentist asked was "Is she a tea drinker?" (No). The second question stunned me, "Is she a swimmer?"
Apparently a few of his swim team patients over the years have experienced discoloration. It's not permanent (he was able to scrap her's off). He didn't explain the chemical reaction taking place.
The optimum pH level in a pool is 7.2 to 7.6.  This pH is considered to be basic.  In general, solids dissolve in acid and then precipitate (or become solids again) in bases.  This means that in a basic swimming pool, the calcium and minerals present in your mouth will harden onto your teeth rather than dissolve (as they would if the pH were acidic - this is why your teeth dissolve slowly when you eat or drink anything acidic.)  The higher pH of the swimming pool, in combination with the antimicrobial compounds that the pool water contains, causes proteins in your mouth to break down and get together with minerals in your mouth to form a hard, yellowish-brown mineral deposit on your teeth.

     The result is swimmer's calculus, hard, brown tartar deposits that appear predominantly on the front teeth. "It's a common cosmetic condition among swimmers," says AGD spokesperson J. Frank Collins, DDS, MAGD. Swimmers who notice the stains should talk to their dentist and perhaps increase their dental visits to three or four times a year, advises Dr. Collins.

The Academy of General Dentistry states the following regarding this phenomenon:

      "Athlete swimmers, who often swim laps more than six hours a week, expose their teeth to large amounts of chemically treated water. Pool water contains chemical additives like antimicrobials, which give the water a higher pH than saliva, causing salivary proteins to break down quickly and form organic deposits on swimmer's teeth.  The result is swimmer's calculus, hard, brown tartar deposits that appear predominantly on the front teeth."

To answer the question, swimming a lot can cause you to get yellow to dark brown stains on your teeth that your dentist or dental hygienist should be able to remove for you at a routine cleaning appointment.

Can Swimming Pools Dissolve Your Teeth?

    As mentioned above, the optimal pH level in a pool is 7.2 to 7.6 - teeth start dissolving at a pH below 5.5.  So... could a swimming pool really dissolve your teeth if it is kept at the optimal pH of around 7.4?  The answer is no.  However, if the pH of the swimming pool finds a way to become acidic, then swimming pools can start dissolving your teeth.  This usually occurs in gas-chlorinated pool systems.  When swimming pools are gas-chlorinated, hypochlorous acid is formed.  Normally swimming pools counteract this acid with a strong base, such as ash.  If the swimming pool doesn't get enough base to counter the acid from the chlorine, it can become acidic and start to dissolve the teeth of those who swim.

     The report, http://www.ncbi.nlm.nih.gov/pubmed/11764119, tells the story of a competitive swimmer who swam in a gas-chlorinated swimming pool and experienced notable dental erosion within 27 days!  It says,  "Several reports indicate an increased prevalence of dental erosion among intensive swimmers due to low pH gas-chlorinated pool water...[A] case report is presented which describes the very rapid occurrence of excessive general dental erosion of a competitive swimmer due to gas-chlorinated pool water within 27 days. The observation of several authors as well as this case underscore the significance of a regular pH monitoring of chlorinated swimming pool water. The high incidence indicates that dental erosion due to frequent swimming is of considerable diagnostic and therapeutic significance. Furthermore, it is recommended to fluoridate the teeth of intensive swimmers regularly to prevent dental erosion."

    The article, http://www.ncbi.nlm.nih.gov/pubmed/8804884, even directly mentions that swimming pools can be a cause of tooth erosion, right along with diet and other factors.  It says that "Swimming pools with a low pH due to inadequate maintenance have...been implicated [in dental erosion]."

     For further reading on dental erosion and swimming pools, you can take a look at the CDC's Morbidity and Mortality Weekly Report from July 22, 1983.  One interesting statistic that they mention is that only 15% of frequent swimmers displayed enamel erosion while only 3% of infrequent or non-swimmers experienced enamel erosion.

    It is presumed that within the past 30 years, swimming pools are much more careful about testing the pH of their water to ensure that it is not too acidic, but it can still happen due to "inadequate maintenance" as the article above states.

Conclusion

     If you notice that you are getting stained teeth due to swimming, you may want to ask your dentist about coming in for more frequent cleanings.

     If you notice that you are losing some enamel on your teeth due to swimming, you may want to check with your swimming pool to make sure that their pH is within the normal range. Also, it may be a good idea to get frequent fluoride treatments from your dentist.