I buy xylitol gum for occasional use. You still need to read labels; even some touted as xylitol gum have crap ingredients.
Well, my dentist recommended that I chew gum because my mouth was a little more dry than he could like. I like the taste of xylitol gum and I've gotten along well with it in the past plus the dentist was happy with my choice.
I don't consider it paleo, but it is my favorite. I buy it at my local "health" store (quotes used because they have a generous share of junk there) and read the label to avoid the worst additives.
I've chewed Pur. I don't know the ingredients off hand, but it was fine enough for me to buy it at the time.
ve heard that resin has been used as chewing gum for many hundred years.
Here you can read about it: http://en.wikipedia.org/wiki/Chewing_gum,
I know they sell chewing gum made of resin in some norwegian health shops. So Im sure you can find them in health shops in your country as well.
I have never tried it, so I don`t have any idea how it tastes.