When people lose teeth?

Well i was wondering when you see people in videos lose one or a few of their front teeth in a fight or an accident. What happens from there i can't see them living the rest of their lifes with a gap in the front of their mouth (especially teenagers where accidents happen most). Do dentists insert artificial teeth or give them mini dentures. And if they just put a few new ones in, then what are they made of? and can you give them for people who need all their teeth and dont have any (old peeps)