Originally Posted by ducnut
Some teeth are shaped different than others, to help pull the chain up onto the big ring. I doubt they're actually hooked, but, probably machined/twisted. Look to see if those oddball teeth are located adjacent to the pins/ramps on the backside of the big ring. If so, then, you know they're supposed to be shaped that way.
Notice the shape of those teeth by the pins and ramps?
also note there's a few variations on this theme, depending on who made the crankset/chainrings and when.