Popular Drinks Eat Away at Tooth Enamel March 9, 2006 (The New York Times News Service) -- Worried about sugary drinks rotting your teeth? A new study suggests that the acid in popular refreshments can bring dental damage, too. Just one day's worth of soaking in Gatorade, Red Bull or Coke ate into the hard enamel surface of teeth, according to a study by University of Iowa researchers. "This isn't so much about sugar as it is about acid," says Dr. John Luther, associate executive director of the division of dental practice at the American Dental Association. "I don't think the public has thought about acidity; they tend to think in terms of sugar." But another expert says the study's design was "too simplistic" and not reflective of daily exposure to liquids by teeth. Dr. Paul Casamassimo, a professor and chairman of the department of pediatric dentistry at Ohio State University, says that "when most drinks -- sports drinks, orange juice, carbonated beverages -- are used the way they are supposed to be, it's not a problem." Most experts agree that the acid in many popular beverages can etch into the thin layer of enamel that covers and protects the exposed areas of teeth. It can also damage the cementum: the hard layer of calcified tissue that covers the unexposed root area of the tooth. "If it erodes far enough it could lead to real tooth sensitivity," Luther says. "If the enamel is gone, then the dentin, which is underneath, becomes more sensitive. Acid eliminates that hard outer covering." In its study, the University of Iowa researchers tested the acid erosion potential of five popular drinks -- apple juice, Coke, Diet Coke, Gatorade and Red Bull. To do so, they immersed four extracted teeth in each of these drinks for 25 hours, replenishing the liquids with a fresh supply of the beverage once every five hours. They then examined the rate of acidic enamel and cementum erosion under a microscope. Gatorade was the worst offender, etching into enamel to an average depth of 131 micrometers, the researchers found. Next up was Red Bull (100 micrometers), followed by Coke (92 micrometers), Diet Coke (61 micrometers) and apple juice (57 micrometers). Results were similar when the researchers compared acid-linked damage to cementum. The findings were to be presented Thursday at the American Association for Dental Research annual meeting in Orlando, Fla. Luther says he was "happy with the range of acidity" covered by the study, and says the findings "really point to the fact that more study is needed." He says he was also intrigued by the fact that high-acidity sugary drinks tended to result in more acidic damage than similar, nonsugared beverages (that is, regular Coke versus Diet Coke). The reasons for that remain unclear, he says. For his part, Casamassimo (who has conducted research sponsored by the company that makes Gatorade) says the long-term exposures employed in the Iowa study don't reflect the way teeth interact with beverages in the real world. According to Casamassimo, the Iowa study "is basically that elementary school science project where you put a tooth in Coca-Cola for a period of time and it dissolves," he says. If that scenario did mirror real-life conditions, "most people would have no teeth left by the time they reached adulthood. That's not the case, of course." In a statement, the American Beverage Association, which represents the industry, agrees with Casamassimo. The Iowa study, "does not reflect real-world situations, and fails to incorporate many factors," the group says. "A more credible study would examined live subjects and more realistic, everyday behaviors." Casamassimo says his own epidemiological study of 300 Ohio State athletes found no connection between particular drinks or foods and dental erosion. Luther acknowledges that acidic drinks can damage teeth, but he stresses that "it's the duration of exposure that's important." "The problem is not only that these drinks are acidic and contain sugar, the problem is that children reach for these drinks and sip on them all day long," Luther says. "Their teeth are being bathed in it." Casamassimo agrees. "I'm a pediatric dentist, and when we see someone who's on a sippy cup all day, that's an eating disorder just like bulimia -- it's in the same category in terms of its effects on teeth," he says. "Or the older kid who sips Mountain Dew with a screw-top cap all day at school." Luther recommends that if a child does have a soft drink with a meal, "that drink should be confined to the meal, and the child should brush and floss (afterwards)." Of course, that's not always easy, especially when it comes to largely unsupervised older children. "Parents really need to try and be aware of what their kids are doing, and too often they aren't," says Luther, who advises that parents make sure their kids get regular dental care. "In my own practice, I've seen severe damage to multiple teeth by children who have habits such as consuming up to 10 soft drinks per day. They do it out of sight." Today's parents may have fewer worries about the impact of soft drinks on their children's teeth than they did a generation ago: A new industry report finds that, for the first time in 20 years, sales of Pepsi, Coke and other brands of "pop" are slipping. As reported Thursday in The New York Times, consumers are abandoning the fizzy drinks for bottled water, sports drinks such as Gatorade and energy drinks like Red Bull.