Sugarless Candy and Tooth Decay:

It is well known that sugar causes cavities, but, recently, dentists have noticed an increase in tooth decay in people who avoid sugar containing drinks and sugared candies.  Many of these products, it turns out,  are very acidic, and it is the acid that is producing the new cavities.

Consumption of sugarless candies, sugarless gum and sugarless soda can contribute to a significant increase in cavities. 

From the Journal of the Massachusetts Dental Society, Fall 2010