If you’ve ever grabbed a sugar-free drink instead of juice or soda because you think this type of beverage is better for your teeth, think again. A recent study published in the Australian Dental Journal shows that even sugarless soft drinks can wreak havoc on our dental health, The Washington Post reports. For decades, dentists have known that sugar destroys teeth when it’s fermented by bacteria in the mouth. The fermentation process forms acid as a byproduct, which ultimately leads to cavities and decay. Until now, it’s always been assumed that sugar-free beverages and sweets helped protect people from these risks.

But recently scientists at Melbourne University’s Oral Health Cooperative Research Center decided to put this theory to the test. Researchers submerged an array of healthy molars—the large, flat teeth at the back of our mouths—in 15 different types of soft drinks commonly sold in schools to see what happened. Surprisingly, scientists found that both sugared and sugar-free drinks eroded dental enamel. Researchers concluded that although sugar-free drinks don’t directly lead to cavities, they may be just as damaging to our teeth as sugar-sweetened beverages. That’s because these drinks contain acids that can strip away a tooth’s enamel and eventually lead to increased sensitivity, pitting and opacity. All these issues drastically raise the risk of developing cavities over time. Researchers also found that milk drinks carried the least risk of tooth decay. What’s more, scientists noted drinking hot water actually helped tooth surface enamel get harder.