Be careful with the xylitol it can kill your yorkie if he or she gets into it! same with sugarless gum or anything else sweetened with it. Don't leg the dogs get it. I imagine other artificial sweetners probably would do the same.
Their bodies process it like real sugar and their sugar shoots sky high, then plummets too low and it can do them in.
http://www.avma.org/onlnews/javma/sep04/040901c.asp
I used Splenda a lot when I was on the Atkins diet, but found it was making me itch really bad. When I quit using it I quit itching.