3 year old still puts everything in his mouth - normal?

My 3 year old son still chews on things and puts everything in his mouth like a baby would. If he finds something on the ground he’ll put it in his mouth. He will chew on all of his toys and sometimes destroy them because he’s got a mouthful of teeth. A few minutes ago I saw him chewing on a Christmas ornament (plastic, not glass). He doesn’t eat them. He just wants them in his mouth.

He’s otherwise typically developing and hits all his milestones. He’s very smart.