The studies found that the majority of soft drinks and sports drinks led to softening of dental enamel - the outer layer of the tooth - by between a third and a half.
Researchers at the Oral Health Cooperative Research Centre (CRC), based at the University of Melbourne, Australia, tested 23 different types of sugar-free drinks - including soft drinks and sports drinks - and found those that contain acidic additives and those with low pH levels cause measurable damage to tooth enamel, even if they have no sugar.
While most people are probably aware of the link between sugar and tooth decay, what is perhaps less well understood is the nature of that link, and why drinks that are acidic - whether they contain sugar or not - can also be bad for our teeth.
Sugar is linked to tooth decay because it forms a plaque on the tooth surface that bacteria digest and convert to acid. It is the acid that attacks teeth by dissolving the outer layers of tooth enamel. Thus, drinks that are acidic - whether they contain sugar or not - can also erode teeth.
Eric Reynolds, a professor at Melbourne Dental School and CEO of Oral Health CRC, says:
"Many people are not aware that while reducing your sugar intake does reduce your risk of dental decay, the chemical mix of acids in some foods and drinks can cause the equally damaging condition of dental erosion."
He explains that at first, the acid strips away the surface of tooth enamel, but then, if it "progresses to an advanced stage, it can expose the soft pulp inside the tooth."
'A measurable loss of tooth enamel'
Oral health experts generally agree that the use of sugar substitutes - including, for example, xylitol, sorbitol and mannitol - in confectionery and beverages has helped to reduce tooth decay in children in industrialized countries.
However, in their newly released briefing paper, Prof. Reynolds and colleagues note that "consumers should be aware that many sugar-free products remain potentially harmful to teeth due to their chemical composition."
The paper summarizes studies in the Oral Health CRC that measured dental enamel softening and tooth surface loss following exposure to a range of drinks.
The studies found that the majority of soft drinks and sports drinks led to softening of dental enamel by between a third and a half.
They also show that both sugary and sugar-free soft beverages - including flavored mineral waters - cause a measurable loss of tooth enamel, with no significant difference between the two types of drink.
Also, six of the eight sports drinks tested in the studies caused loss of dental enamel. The two that did not had a higher calcium content, note the report authors.
The Oral Health CRC recommend that sugar-free products - including soft drinks, confectionery or candy, and sports drinks - should carry labels with information that helps consumers evaluate them in relation to their oral health.
'Current product testing and labeling regulations are insufficient'
Prof. Reynolds says "sugar-free" does not mean a product is safe for your teeth and adds:
"We have even found sugar-free confectionery products that are labelled 'toothfriendly' and which when tested were found to be erosive."
He and his colleagues suggest people check for acidic additives, such as citric acid and phosphoric acid, in the ingredients list when deciding which sugar-free products to buy.
They also suggest that after eating or drinking acidic products, you should not brush your teeth straight away, as this can remove the softened tooth layer. Instead, rinse your mouth with water and wait for an hour or so before brushing.
And if you drink acidic beverages - such as soda pop - on their own, then chewing sugarless gum afterward can help to increase saliva flow to neutralize the acid.
The Academy of General Dentistry, an organization of North American dentists, explain that because saliva helps neutralize acids and wash your teeth clean, the worst time to drink beverages high in acid, such as soda pop, is when you are thirsty, due to low levels of saliva.
Soda pop and other carbonated drinks are acidic because they contain carbonic acid - which results from dissolving carbon dioxide into them to make them fizzy.
Experts suggest you quench thirst with water, a much healthier alternative to soft drinks, pop or sports beverages.
Also, regular check-ups with your oral health professional can help to detect early dental erosion, which can usually be reversed with treatments to replace lost minerals. If the erosion is more advanced, then the lost surface may need a filling or a crown.
In their briefing paper, Prof. Reynolds and colleagues conclude:
"In light of its studies, the Oral Health CRC is of the view that current product testing and labeling regulations for foods and beverages are not sufficient to enable consumers to make informed choices in order to avoid the risk of dental erosion."
Meanwhile, Medical News Today recently learned that children exposed to secondhand smoke have double the risk of tooth decay. Writing in the BMJ, a team of researchers from Japan shows how children exposed to secondhand smoke at 4 months of age have a higher risk of tooth decay at age 3 years.