Is drinking sparkling water bad for your teeth?

Carbonated water doesn’t contain any sugar or artificial sweeteners, but the carbon dioxide that makes it fizzy makes it acidic, as do the flavors added to it. This acidity varies significantly from product to product. What effect does it have on dental health? Can you drink lots and lots of it?

Carbonated water is all the rage. At the grocery store, it comes in a thousand and one brands, but also in a thousand and one flavors: lemon, blackberry, pineapple… And at home, Sodastream devices are gaining popularity. In 2019, 6% of Canadian households owned one.

The consequences of sugary drinks on dental health are well known and well documented. Bacteria convert sugar into lactic acid, which causes cavities.

The acidity of the drink also has an impact on the teeth, but in a different way. When exposed to an acidic solution, the enamel on the surface of the teeth dissolves and softens temporarily – it then becomes subject to erosion, a problem that now affects between 30% and 50% of children (baby teeth) and between 20% and 45% of adults.

Saliva, fortunately, has a buffering power: its ions remineralize the enamel and therefore make it harden again. “Saliva does its part to remineralize the enamel, but if the teeth are constantly attacked by acid, eventually, there will be an erosion effect,” explains Liliane Malczewski, president of the Ordre des dentistes du Québec.

The more acidic the drink, the higher the risk of erosion. In vitro studies clearly demonstrate this.

Thresholds

Neutral water has a pH of 7. A pH greater than 7 indicates that the water is alkaline and a pH less than 7 indicates that it is acidic. The lower the pH, the more acidic the solution.

At what pH does enamel begin to dissolve? Studies of plaque suggest a threshold of 5.5, but for erosion, the risk becomes substantial below 4, says John D. Ruby, assistant professor of pediatric dentistry at the University of Alabama at Birmingham.

In 2016, his team tested the pH of 379 beverages and came up with the following scale: a beverage is “minimally erosive” when its pH is equal to or greater than 4; “erosive” when the pH is between 3 and 3.99; and “extremely erosive” when it has a pH less than 3. “Anything below 4, the less you drink, the better,” summarizes John Ruby, reached by The Press.

Tooth enamel does not regenerate. Severe erosion can lead to exposure of dentin, hypersensitivity and even loss of the affected tooth.

“If you have a thinner layer of enamel, the decay will also progress more quickly,” warns Dr.^D Malczewski.

Read the study (in English) published in the National Library of Medicine

Among the most erosive drinks, we find carbonated drinks (with or without sugar), sports drinks and juices. These highly acidic drinks are therefore the main enemies to be defeated, well before carbonated water: their overconsumption would be the first extrinsic cause of dental erosion (gastric reflux being the main intrinsic cause).

Sparkling and mineral waters

When Professor John Ruby’s team tested them, the carbonated waters had varying pHs, with the least acidic having a pH of around 5, and the most acidic (Dasani flavoured waters containing citric acid) having a pH of 3. The tests, carried out at the laboratory of the Faculty of Dentistry at the University of Montreal at the request of The Press showed similar gaps.

Acidity is an indicator of a drink’s erosive potential, yes, but other factors come into play, explains Caroline Nguyen Ngoc, associate professor in the department of restorative dentistry at the University of Montreal.

Citric acid has a much higher erosive potential than carbonic acid (which results from adding carbon dioxide to water), says Caroline Nguyen Ngoc. What types of acids raise the pH of flavored waters like Bubly or Aha? It’s hard to say, since the exact ingredients are hidden under the terms “natural essence” or “natural flavor.” The precise formulas are “confidential,” says the website of PepsiCo, which distributes Bubly products. “A lemon and an orange are natural, but they are very acidic fruits,” says Caroline Nguyen Ngoc.

Another factor to consider: the mineral content found in the tooth (calcium, phosphorus) and fluoride in the drink. For the same pH, calcium-fortified fruit juice, for example, is less erosive than regular juice. How can you tell if your sparkling water is saturated with minerals? It’s difficult to determine, but we could, for example, favor “mineral” waters, suggests Caroline Nguyen Ngoc.

Finally, notes the professor, the buffering power of saliva varies from one person to another, by its composition and quantity. With age, and with the taking of medication, the quantity of saliva tends to decrease.

Moderation

But what probably matters most is the frequency of consumption. Dentist John Ruby gives the example of wine, which has a pH of between 3 and 3.8. “If you have a glass of wine with dinner, I don’t think you’re at a significant risk of dental erosion,” he says. Wine tasters, however, are at risk, especially as their careers get longer.

When sparkling water has a pH above 4, or even above 5, can we drink it without restraint? Can we completely swap still water for sparkling water if it is not flavored?

“It’s a pleasure to drink your own mineral water – and I do it too. But I don’t sip sparkling water all day long,” says Caroline Nguyen Ngoc. “Having your mouth in an acidic environment all the time? I wouldn’t recommend it.”

Professor John Ruby ends with this universal advice: “In Quebec, you are lucky to have wonderful water. Drink it.”