The Godfather..Marlon Brando?

I've been trying to watch The Godfather lately but have been too tired to get past the part where Don Vito gets shot in the back. But I can't help but try to figure out if Marlon Brando's jowls are real or not. I've looked at young pics of him but it looks like to me that he put stuff in his mouth? Does anyone have any idea if theres inserts in his mouth?