Sugar can destroy teeth when it is fermented by bacteria to produce acid that leads to decay. The condition is extremely common: In the United States, about one in four children ages 2 to 5 had dental caries or cavities in their first set of teeth, according to the National Health and Nutrition Examination Survey conducted in 2011–2012. Among those aged 6–11, 21 percent had had cavities in their permanent teeth. And among those 12 to 19, it was a whopping 58 percent.
While sugar-free foods won't lead directly to cavities, the researchers found that many can strip away a tooth's outer layer -- leading to chalkiness of the tooth's surface, pitting, opacity, tooth sensitivity and other issues. That's because they contain acids like phosphoric acid (found in colas) or citric acid (found mainly in lemon and lime flavored drinks).
“Therefore, banning sugar-containing beverages from schools may have positive health effects for reducing obesity, diabetes and dental caries but it may not reduce the risk of dental erosion," Eric Reynolds, an oral health professor, and his co-authors wrote in the Australian Dental Journal.
The researchers tested 15 soft drinks sold in schools on healthy human molars that had been extracted and found that all of them led to significant erosion of the dental enamel, with no difference between sugared and sugar-free drinks. This table from their report shows that the sugared and non-sugared soft drinks are the worst in terms of their acid content, followed by sports drinks.
In testing eight brands of sports drinks, they found that all but two of them caused significant loss and softening of the enamel surface -- although the effect was significantly less severe than with a soft drink like Coca-Cola, which was used for comparison. Note how water, which was used as a control, actually had a positive effect on the surface enamel.
Standard pH tests, which indicate how acidic a liquid is, show that sugar-free candy can be similarly destructive. Of 32 commercially available sugar-free confections that were tested, 22 had a pH level below 4.5, which is below healthy levels required to maintain the integrity of tooth enamel and prevent tooth demineralization.
What does all this mean, practically speaking?
The researchers recommended that when it comes to drinks you may want to minimize both sugared and sugar-substitute beverages and choose the most basic, old-fashioned way of rehydrating -- water. Fluorinated water is even better. If you must drink or eat an acidic product, rinse your mouth out with water afterwards and wait an hour before grabbing that toothbrush. Brushing immediately can remove the softened layer of tooth.
Choose mint or menthol flavored sugar-free confections and avoid those that are fruit flavored, particularly lemon.
Sugar-free gum is still okay. In fact, the researchers said it can stimulate saliva flow, rinse away acids and reharden softened tooth enamel.
The American Beverage Association, an industry group, said in a statement on Monday that an individual's susceptibility to dental caries and erosion is determined by a number of factors, including lifestyle, diet and genetics as well as the types of foods consumed, the length of time foods are retained in the mouth and the level of oral hygiene.
"Characterizing beverages, such as juices and soft drinks, as a unique cause of dental caries or tooth erosion is overly simplistic," the ABA said. The organization also noted that low- and no-calorie sweeteners have been proven safe by the U.S. Food and Drug Administration and its counterparts around the world and that it feels there is "no reason why the average individual should avoid them."
This post has been updated.
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