Cassidy's teeth

Kelley reports that Cassidy apparently chewed off the corner of a tupperware lid, while rumaging in the cabinet we had left open for her. Intervention was necessary, choking was avoided. But what is with these kids? With Aidan we had a trip to the emergency room when he bit off a piece of the wooden spoon we'd given him to play with. If tupperware and wooden spoons aren't safe playthings for a sub-1yr old, what is?