Why has she started chewing at 1 ?

by Stephanie
(Michigan)

I have a one year old mini schnauzer. No problems with chewing inappropriately while she was teething because I provided a variety of chew toy choices. Just lately she has decided to steal and chew paper,envelopes and napkins which she will shred unless I catch her. If I do she will very proudly bring them to me in exchange for a treat. She is also gnawing on her food bowl and tearing apart her Kong bed. Could she still be teething, or is this just naughty behavior and how do I stop it?