"There's no question that chewing any kind of sugar-free gum can reduce cavities," advises Dr. Colin Dawes in the Faculty of Dentistry at the University of Manitoba in Winnipeg, Canada. "When we chew gum, we increase the flow rate of saliva in our mouths, and that can lead to better oral hygiene."

Dawes, a world authority on saliva, has conducted tests on chewing gum to measure their effects on saliva flow and on dental plaque. Saliva neutralizes acid in plaque, flushes out food particles in the mouth and helps recalcify teeth. In one study, chewing gum increased the rate of saliva flow in the mouth by a factor of twelve.

"What happens is that the increased flow rate changes the composition of the saliva and helps neutralize the acids that cause tooth decay," he explains.

Furthermore, sugarless gums are better than sugared gums, he notes, because the sweeteners in sugar-free gum won't convert into decay-causing acid in the mouth.

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