Soft drinks vs. hard enamel: which is stronger?

Chris Langley
23 January 2012

Have you ever gone to the dentist and, while working their magic on your teeth, they correctly guess the sort of food and drinks you’ve had lately? This mysterious feat of dental clairvoyance may seem impressive at first, but the evidence is written all over your teeth!

Your teeth are composed of four tissues; enamel, dentin, cementum and pulp. Pulp and cementum are buried in the roots of your teeth, while dentin forms a secondary protective layer underlying the enamel that makes up a tooth’s outer surface. Composed primarily of calcium, enamel is the hardest substance in the human body (harder than bone) but, despite its incredible strength, enamel is highly vulnerable to one of the most common ingredients in fruits and soft drinks. It’s not sugar and it’s not artificial colouring. It’s acid.

Did You Know?
Enamel is your teeth's first line of defence against bacteria and the pressure that comes with chewing. Weakening your enamel can lead to a variety of complications, most notable of which is cavity formation.

Acids, like phosphoric acid, which are added to soft drinks to give them that sharp flavour, and citric acid, which occurs naturally in citrus fruits and gives soft drinks their sour taste, break down tooth enamel by a process called "demineralization". Demineralization occurs when the acids strip calcium away from the tooth’s surface, eventually revealing the soft, susceptible dentin underneath and allowing for rapid cavity development. It is this reduction of your teeth’s protective enamel coating that dentists see when you go in for checkups and if it’s particularly thin, especially in your front teeth which are bathed in beverages guzzled from a glass or can, they can usually tell what you’ve been drinking. As enamel thins, it becomes transparent and is easy to spot because it makes the edges of your teeth see-through!

Did You Know?
You can reduce the risk fruit and soft drinks pose to your teeth by drinking them with a straw, sparing your enamel an acid bath.

Before you purge your fridge of juice and pop, you should know that demineralization is a reversible process. "Remineralization" happens every time you brush your teeth and consume calcium-rich foods/drinks by reinforcing your enamel with fluoride and calcium, respectively.

Fast Fact: The “safest” soft drink for teeth is root beer because it’s the least acidic. Root beers are often non-carbonated and contain little to no phosphoric and citric acid, unlike their enamel-destroying counterparts.

So the next time you’re wondering why your dentist gets grumpy when they discover your acidic eating habits, you’ll know why they’re so concerned.

Learn More!

The role of fluoride in preventing tooth decay

Guide to brushing your teeth

Introduction to enamel from You Tube


General enamel information

Acids in soft drinks

Acids in fruit/fruit juice

Study that determined root beer was least acidic soft drink

Article first published on August 27, 2010.

Chris Langley

Chris is a graduate student at the University of Guelph where he studies molecular and cellular biology - more specifically the bioremediation of environments polluted by harmful pesticides and the detoxification of chemical warfare agents using bacterial proteins.  Chris obtained his undergraduate degree in microbiology and he's worked at Campbell's Soup Canada, in Toronto, developing new soups that are now on grocery store shelves (you might have tried some!).  Chris has also spent time at the National Research Council of Canada in Ottawa as an antibody engineer in search of a vaccine against the avian flu.  In his down time Chris likes to watch and read sci-fi movies and books, play piano/guitar, work on graphic design projects and write scientific articles for the general public.

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