Teeth whiteners shine compared to acidic juice

U. ROCHESTER (US)—The ingredients used in over-the-counter teeth whitening products are gentle compared to acidic fruit juices, a new study shows.

Researchers at the University of Rochester’s Institute for Oral Health found that orange juice markedly decreased hardness and increased roughness of tooth enamel. They also found that hydrogen peroxide, the common ingredient in teeth whiteners, caused no significant change in hardness or surface enamel.

Unlike ever before, researchers were able to see extensive surface detail thanks to a new focus-variation vertical scanning microscope. “The acid is so strong that the tooth is literally washed away,” says YanFang Ren, whose findings were recently published in Journal of Dentistry. “The orange juice decreased enamel hardness by 84 percent.”

Weakened and eroded enamel may speed up the wear of the tooth and increase the risk for tooth decay to quickly develop and spread. “Most soft drinks, including sodas and fruit juices, are acidic in nature,” Ren adds. “Our studies demonstrated that the orange juice, as an example, can potentially cause significant erosion of teeth.”

It’s long been known that juice and sodas have high acid content, and can negatively affect enamel hardness. “There are also some studies that showed whitening can affect the hardness of dental enamel, but until now, nobody had compared the two,” Ren explains. “This study allowed us to understand the effect of whitening on enamel relative to the effect of a daily dietary activity, such as drinking juices.

“It’s potentially a very serious problem for people who drink sodas and fruit juices daily,” says Ren, who added that dental researchers nationwide are increasingly studying tooth erosion and are investing significant resources into possible preventions and treatments. “We do not yet have an effective tool to avert the erosive effects, although there are early indications that higher levels of fluoride may help slow down the erosion.”

In the meantime, Ren advises that consumers be aware of the acidic nature of beverages, including sodas, fruit juices, sports, and energy drinks. The longer teeth are in contact with the acidic drinks, the more severe the erosion will be. People who sip their drinks slowly over 20 minutes are more likely to have tooth erosion than those who finish a drink quickly.

A Texas-based company, Beyond Dental and Health, sponsored the trial in part by providing the 6 percent hydrogen peroxide.

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