I have been told that Carbon Dioxide (CO2) dissolved in carbonated water produces carbonic acid, that can attack your tooth enamel.

The Daily Mail claims:

believe it or not sparkling water is almost as damaging to your teeth as flavoured fizzy drinks. This is because your teeth are constantly being bathed in a weak acid solution containing carbon dioxide - thought to wear away our teeth. After repeated attacks over several years, this acid can erode the enamel - the hard part of our teeth made from calcium salts.

Is there any evidence that this is a significant cause of tooth damage, in the dosages one might expect to drink?

I know there are other questions asking about flavoured sodas (e.g. Does (diet) soda cause tooth decay?), however, my question is about unsweetened and unflavoured tap water, that has been carbonated with CO2.

  • Welcome to Skeptics.SE! We are looking for notable claims - claims made by, and believed by, other people, not for your own speculation. With a bit of work, I think we can turn this into a better question. – Oddthinking Aug 18 '14 at 3:45
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    That's interesting, since (according to wikipedia at least) breathing causes carbonic acid as well. if this is true, breathing is bad for your teeth. – Timothy Groote Aug 18 '14 at 8:44
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    @TimothyGroote I'm pretty sure the quantity of carbon dioxide in your breath is far less than the amount found in carbonated water. – March Ho Jul 22 '15 at 4:24

A journal article on the topic found a negligible (but non-zero) effect of carbonated waters on tooth enamel. The claim in the Daily Mail is clearly in dissonance with the results from this study.

Dissolution levels with all of the mineral waters were very low and for several still waters were undetectable. (...) De-gassing of a sparkling mineral water reduced its dissolution, but the total levels were still relatively low suggesting that carbonation of drinks may not be an important factor per se in respect of erosive potential. The complex and heterogeneous mineral compositions of mineral waters could influence the dissolution equilibrium of apatite in enamel and controlled addition of several ions to ultrapure deionized water was investigated.

(source: J Oral Rehabil. 2001 Aug;28(8):766-72)

The idea that carbonated water harms teeth may be based on the fact that dissolving carbon dioxide in water results in some carbonic acid. However, this did not result significant enamel decay.

When carbon dioxide is dissolved in water, small amounts of carbonic acid are formed, making the water slightly more acidic. However, when researchers soaked human teeth in various still and sparkling waters, they found that neither were harmful to the teeth.

(source: Nutrition Diva: Is Carbonated Water Bad for You?)

  • So the answer is Yes, it does harm your teeth according to these sources and this one bellow. An "negligible" harm is quite an imprecise term that would need to be scientifically quantify. The difference between "none" and "negligible" and "high" may vary greatly depending on your consumption. Using vague term such as "negligible" might more profit some companies than you teeth. ncbi.nlm.nih.gov/pmc/articles/PMC2676420 – JinSnow Jul 21 '15 at 8:54
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    The answer is actually No, there is no evidence to suggest that carbonated waters are a significant cause of tooth damage, where significant is an important word, as the effect was non-zero. The study you link to is not about carbonated water, but about soft drinks. – Spork Jul 21 '15 at 9:09
  • I will check again I might be wrong. – JinSnow Jul 21 '15 at 9:21
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    @GuillaumeCombot A single atom being knocked out of place makes "none" a technically inaccurate statement. Negligible is an extremely important word even if not precise – Richard Tingle Jul 30 '15 at 16:07

Yes, it does harm your teeth, less than the most aggressive drink, but still.

You could answer the question "Does unflavoured carbonated water cause damage to teeth?" in two ways. The first way by a "yes or no" answer, which correspond to my understanding of the question. The second way is "yes but no, so no" which is the point defended by Victorhooi.

Thanks to Oddthinking we found a study about unflavoured carbonated water.

"Sparkling mineral waters showed slightly greater dissolution (1) than still waters, but levels remained low and were of the order of one hundred times(2) less than the comparator soft drinks. De-gassing of a sparkling mineral water reduced its dissolution (3), but the total levels were still relatively low suggesting that carbonation of drinks may not be an important factor per se in respect of erosive potential."

  1. (1.1) This point shows that sparkling water is still more corrosive than still water. (We all agree that sparkling water is less corrosive some aggressive soda. But the question was not "is sparkling water better than flavoured soda or chloric acid?")

  2. (1.2) It does dissolve, but "hundred times less than the comparator soft drinks". (The study could also have added "and probably several hundred time less than chloric acid"). Cf. point 1 above

  3. (1.3) shows that carbonated gas causes erosion, which mean that you take relatively more risk by drinking carbonated water (but less than drinking a soda, or chloric acid).

According to the studies cited by Spork, the answer should be "yes it does harm your teeth" because a "negligible harm" is still a harm —that could be avoided. That's my point. On this topic Timothy Groote interestingly suggest that breathing causes carbonic acid. If it does, it suggest 3 things:

  1. (2.1) it would be interesting to measure the difference level of erosion between our breathing and the carbonated water.
  2. (2.2) you can't probably avoid breathing through the mouth, but you can choose what you drink.
  3. (2.3) just to say: what is "natural", or "normal" is not necessary "good"

Concerning the difference between "none" and "negligible" and "high". Those are very subjective: they may vary greatly depending on what your criteria of comparison (chloric acid, coca cola or milk?), but also of you consumption frequency and also of the type of mineral water you will ingest (in which the ph and the chemical compounds may vary greatly, because there is many kinds of carbonated water. Eg. The study above talk about calcium minerals that could slow the erosion). A corrosion index/scale would be much more precise.

The lack of precision of such terms such as "negligible" might more profit some companies than you teeth. Eg: "the total levels were still relatively low" "carbonation of drinks may not be an important factor" "their effects were moderated" (J Oral Rehabil. 2001 Aug;28(8):766-72). To get a complete idea we must also take into account that studies are often founded by lobbies.

My last point is about chemical reaction In brief (any) acid source break teeth enamel. A wikipedia article talk about it.

  1. (3.1) Although carbonated water contains nothing more than carbonated gas and water (with a few minerals) it is still very acidic due to the carbonation which can combine with the water to form carbonic acid.

  2. (3.2) The pH value is clearly an important variable in the erosive potential of beverages (dental Acid erosion source )

We can safely assume that carbonated water has a (limited, but still) corrosion effect on teeth since the carbonic acid will dissolves the calcium compounds of enamel due to the acidity.

EDIT: I did update my answer according to Oddthinking study.

Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.

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    The claim was that carbonated waters are nearly as damaging to teeth as fizzy drinks. This is false. The claim that they are not bad for your teeth is a different question. Anything out of moderation is bad for you (and ultimately your teeth), including plain noncarbonated tap water. – Spork Jul 21 '15 at 9:30
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    This is a theory based answer, and those are not considered acceptable on this site. The pH value may be an important variable, but it is not the only variable. For all we know, the effect of the acidity is compensated by some other beneficial factor in sparkling water. To know for sure, we need to see an experimental study that tests actual sparkling water on actual teeth. – Nate Eldredge Jul 21 '15 at 11:18
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    The result from the paper you cite is interesting, but it is explicitly limited to flavored water, and the question is explicitly limited to unflavored. – Nate Eldredge Jul 21 '15 at 11:19
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    "no study have been made/funded to prove" - this is a claim that needs a reference. – Oddthinking Jul 25 '15 at 7:47
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    Here we go - a direct contradiction to your claim. They compared sparkling mineral water to de-gassed sparkling mineral water (and other soft drinks). – Oddthinking Jul 25 '15 at 16:00

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