hello...doctor, I have 2yr old boy he is having the habit of keeping every thing in the mouth even toys, he will try to sepetare toy parts with mouth even it's not capable to remove, yesterday he was playing with the car trying to remove the wheel when I saw there is nothing in his mouth but later I find out 1small wheel is missing from the car, I haven't found anywhere in the house, I'm very much worried about the wheel I don't know whether he swallowed it or not, he is doing good eating well sleeping and happily playing, what if he swallowed can it pass by itself through the motion??