It can help prevent tooth decay, as long as you choose a sugarless gum. Acid forms in your mouth after eating food or drinking sugary drinks. This acid would otherwise attack the tooth and cause tooth decay. Chewing gum helps to produce saliva. Saliva is naturally alkaline and neutralises the acid. It also helps to wash away acid as it builds up.
The minerals generated in the extra saliva can even help strengthen your tooth enamel, which reduces your risk of a dental cavity. This would also help to counteract the acidity of some food types such as citrus fruits and fizzy drinks which will also wear down the enamel on teeth. People who suffer from gastric reflux (acid coming into the mouth from the stomach) or regular vomiting (e.g during pregnancy) would benefit from gum for this reason.
Parents can share this tip with children and teens, who often chew gum. Just be sure that they choose sugarless gum, not a sugary bubble gum, which can have the opposite effect and contribute to the buildup of plaque on teeth.
Gum-chewing is not a substitute for a regular routine of twice-daily tooth brushing and flossing but will help to keep the teeth healthy when done is combination with these.