Depends. Cavities occur for many reasons but mostly because of what you eat, like sugared food and drinks. The natural protectors of teeth are your saliva and fluoride, which can be found in many wells or city water supplies to make levels optimal.
Your saliva benefit comes from flow (where chewing gum can help) and mineral content. Sugared gums would be bad. Gums containing xyletol actually can help prevent cavities too much chewing, though, can make your jaw sore and that can be a whole different problem.
