What are options if 2 front crowns break off teeth at gum line?

Firstly, when you get front caps (not crowns ... they are for molars) your teeth are files down to points and root canal is usually done with a small "post" inserted to strengthen the tooth. It is going to be entirely up to your dentist to decide what to do. You two teeth may have weakened and they may have to be pulled and perhaps you will end up with a bridge. I have one tooth out on the left front and one on the lower and I have a bridge and you can't tell I don't have all my teeth.