If your chewing gum contains sugar, you're essentially "bathing" your teeth in sugar while you chew away. This can contribute to tooth decay. Even if you chew sugar-free gum, there are still risks to your teeth because sugar-free gum often contains acidic flavorings and preservatives that may in fact lead to dental erosion,4 even if it contains cavity-fighting xylitol. Unlike cavities, dental erosion is a process of incremental decalcification, which, over time, literally dissolves your teeth.