Chewing Gum: The Good and Bad
Chewing gum can affect teeth positively and negatively. Gum sweetened with sugar, like most bubble-producing varieties are, can create cavities in teeth by reacting with the bacteria in dental plaque to produce enamel-eroding acids. Gum sweetened with sugar can do significant damage because it doesn't dissolve, and can get pressed against teeth for longer periods of time than candy.
The act of chewing, however, is good for your teeth. Chewing promotes the production of saliva, which helps wash away food particles from around teeth and gums while neutralizing the acids that cause tooth decay.
These benefits are not enough to make chewing sugary gums beneficial. When your child chews sugar-filled gum, they are doing their teeth more harm than good as long as there is still sugar or flavor in the gum. If they keep chewing long after the gum has lost its taste, the benefits may win out, but few kids will continue chewing old, flavorless gum when there is a fresh piece nearby.