What about gum chewing?

Besides the sugar in gum being damaging to the teeth there is another harmful problem to consider and that is: “teeth and jaws weren’t designed for more than a few minutes of solid chewing per day-far less than the two hours clocked in daily by hardcore gum chewers. All this chewing results in inordinate wear on the jawbone, gum tissue and lower molars, and can change the alignment of the jaws” says Michael Elsohn, D.D.S., in the Medical Tribune.