That Sparkling Smile is related to the seasonal world event Hallow's End. Completing this achievement is criteria for the meta achievement .
A stack of ten Tooth Picks is one of the random drops from during the Hallow's End event. A Handful of Treats can be obtained by looting the Candy Buckets during the or in a after freeing a town from the Shade of the Horseman. The stack of ten Tooth Picks has a fairly low drop rate.
When lvl 90 the drop rate is about 80%.