What to do if i have two teeth that have good-sized chunks missing from them.do i need a root canal?

Probably: You may also need crowns. But your local dentist who will treat you will take radiographs to determine the extent of the damage and what treatment you need. I cannot diagnose you over the internet for this problem.

Urgent dental visit: An x-ray and a quick test can determine if you need a root canal, but those holes will not get smaller by themselves. See a dentist asap so you can have the most conservative treatment options presented.

can vary: Depends on the extent of the tooth broken and what part..Root canal would be done only if the nerve exposed..Otherwise just restored with a fill if small and crown if big after building up the tooth..See your dentist soon so they can restore and prevent root canal if not needed before it gets worse ..