Chocolate, chewing gum and red licorice are not as bad for your teeth as you thought.
But the bad news: Bread, bananas, raisins, cereals and chips are probably worse, according to the latest dental research.
"We used to think it was sugar, sugar, sugar -- and just sugar -- that caused cavities," said Thomas Truhe, a Princeton, N.J., dentist who spoke at the annual Thomas Hinman Dental meeting in Atlanta this month. "Now we know that's not true."
Starches may be harder on teeth than the sugar found in candy, Dr. Truhe said, because starches dissolve in the mouth slowly and sugar often clears the mouth quickly.
Starches are complex carbohydrates; sugars are simple carbohydrates. But to the bacteria in plaque -- the sticky substance that adheres to teeth -- all sugars are essentially the same.
The bacteria in plaque metabolize any kind of sugar, including the so-called "natural sugars" in unprocessed foods, and leave behind an acidic waste. Over time, that acid causes the teeth to lose minerals. A cavity is thus created.
What you eat is not as important as how frequently you eat it, Dr. Truhe said. Almost any food will provide fodder for bacteria and acid and increase the risk of cavities.
Dr. Truhe, co-director of the Princeton Dental Resource Center, which publishes dental research findings, said the most effective way to combat acid is by brushing with fluoride toothpaste. It deposits microscopic beads of calcium fluoride that help neutralize acid.
And certain foods actually seem to help inhibit cavities.
Cocoa products -- including chocolate -- and coffee, tea and beer all contain tannin, an acid that is as effective in preventing tooth decay as fluoride, according to research at the University of California School of Dentistry in Los Angeles. The research, done with rodents, shows that tannins prevent bacteria from sticking to tooth enamel.
Other research indicates that the flavoring in red licorice -- glycyrrhizin -- inhibits the loss of minerals from teeth that, over time, causes cavities to form. Research at the University of Iowa's dental school shows that the same is true of the milk proteins, calcium, phosphate and fats in chocolate, and aged cheeses.
But bread, bananas, raisins, dry cereals and chips -- to name a few -- are more dangerous to the teeth than most people think, he said.
Tiny particles lodge between the teeth and near the gum line. As the food decomposes, it acts like "little sugar reservoirs" for as much as two hours. Such foods are actually more likely to cause cavities than chewing gum, caramels, jelly beans and taffy.