Please be careful pushing xylitol, "sugar alcohols" are neither a sugar or an alcohol. This, of course, is exactly the thing that makes them desirable as a sweetener substitute, the body doesn't really know what to do with the stuff, and, presumably, neither do common mouth bacteria. Sugar alcohols are known for causing digestive troubles, for this very reason, with the most notorious example being the Haribo "sugar free" gummies that caused diarrhea.

Small quantities in gum may be fine but sugar alcohols are increasingly being added to foodstuffs, and I'm increasingly dubious about it.