Love soda? Brushing teeth right after drinking may damage enamel

Everyone brushes their teeth to clean them, but brushing right after drinking soda might do more harm than good. Soda's extreme acidity may soften and erode tooth enamel, and brushing right after drinking could worsen the damage.

According to new research done by dentists at Germany's Goettingen University, waiting 30 to 60 minutes after drinking soda to brush helps to protect tooth enamel. Waiting allows it to recover from erosion through the buffering agents and minerals in saliva.

In the experiment done by the university, 11 volunteers wore a removable prosthesis of tooth-like material for three weeks. Every morning and evening, the volunteers soaked the prosthesis for 90 seconds in a liquid similar to soda and then waited different times before brushing it. At the end of the study, researchers measured the thickness of the enamel on the simulated tooth to determine the amount of damage. The longer the subjects waited to brush, the less the enamel was damaged.

Normally the mouth has a pH of 6.2 to 7, which is close to neutral with no damage being done to the teeth, according to, a toothpaste company's Web site. If the pH reaches below 5.5, then the enamel begins to demineralize and weaken. Soda has an average pH of 2.5, which is far below the point where enamel demineralizes. Phosphoric acid is the ingredient in soda which causes it to be so acidic. Saliva raises the pH back to normal and it contains minerals which strengthen the tooth enamel.

Tooth enamel erosion is extremely harmful because it weakens the tooth and makes it prone to breakage, said Dr. Paul Hughes, who has operated dental practices in Park Forest and Snowshoe for 18 years. The enamel is the hardest quartz-like substance in the body, but it becomes porous and soft when exposed to acid.

"Enamel wears out faster when it's been weakened," he said. "It's meant to be in one piece and to last you a lifetime."

Some enamel damage such as white spots, chalky areas on the teeth can be repaired through the use of prescription fluoride toothpaste that hardens teeth. Deeper damage that extends to the root can be repaired through caps and fillings.

Not all dentists agree with waiting to brush. Hughes said that the sugar, not the acid, in soda is the problem.

"Soda has a high amount of refined sugar such as fructose and sucrose," he said. "Bacteria process the sugar and produce acid which dissolves the enamel. The acid in soda doesn't come in contact long enough to do damage."

The duration of the time the teeth are exposed to soda is important as to how it affects teeth. One quick drink allows teeth to recover, but many sips over a long period of time keeps on bathing teeth in sugar and acid.

"The frequency makes a difference," Hughes said. "It wouldn't matter if you drank two liters at one time, but sipping soda is like a continual acid attack."

"Soda is so popular because of its price, availability and peer culture," said Jill Patterson, assistant professor of nutrition.

Every year at the dining commons, 42,625 gallons or 545,600 10-oz. glasses of soda are consumed, said Lisa Wandel, associate director of Food Services. That doesn't include FruitWorks, iced with lemon and sugar, unsweetened iced tea and pink lemonade.

"We are a customer-driven service," she said. "We do offer alternatives like milk and juice. So students are old enough to make their own choices about what to eat."

Choosing alternatives to soda may improve nutrition, but can be equally harmful to teeth in terms of acidity and sugar. Orange juice has a pH below 5.5. When comparing sugar, a 12 oz. can of soda has 140 calories mostly from simple sugars and a 8 oz. glass of orange juice has 100 calories from simple sugars, Patterson said.

"Juices are often fortified and contain more vitamins," she said. "Some cheap and unfortified juices such as apple juice made from concentrate are the equivalent of sugar water, so you need to read the label."

"Most students probably don't brush right after meals because they're running between classes and getting a quick bite to eat," said Marissa Zion (freshman-division of undergraduate studies).

Hughes recommends chewing sugarless gum between meals if brushing isn't possible. Chewing simulates saliva, which is beneficial for cleansing teeth. Water also helps by washing away food.

Contributed by Asmaa Yousef

Source: http://www.collegian.psu.edu/archive/2003/10/10-21-03tdc/10-21-03dscihealth-04.asp