I wish I had seen this sooner before your trip to the vet. I immediately knew what it was as my Tinkerbell has done this 3 times with my son's army men. We have had to throw all army men away because she is obsessed with finding them and chewing off their heads. The plastic locks her back teeth together and I have had to pry it out while she is flipping out scared.
I'm glad you're baby is ok!