Accidents happen. Whether you were watching your child when it happened, you weren't watching when it happened, it happened under the watch of someone you trust with your children or not... accidents just happen.
Recently I read an article on CNN about what to do in an emergency situation after an accident happens, and it is not what you think. The old wives' tales tell us to put a tooth that has been knocked out in milk or a fingertip that has been severed on ice; these home remedies are actually completely wrong and could cost you or your child their body part.
As it turns out, while milk does contain calcium, it is its perfect PH balance of 7 (just like water) that makes it great for rinsing off teeth that have been knocked out. However, the procedure for dealing with a knocked out tooth is not to place the tooth in a cup of milk and head for the emergency room as we have all been told. What actually needs to be done with a tooth that still has the root attached is to be cleaned and placed back into the hole that was created when it fell out. While your child might be losing their teeth naturally and you have nothing to worry about, once those adult teeth grow in, those are all your child has and this could be critical.
You can learn all about the exciting (and totally gross) things that you can do to help your child in an emergency situation such as this one in the article here.