Agressive behavior

have 4 cats ages 6, 5, 3 and 1. The last two months the 5 year old has suddenly become very aggressive toward the 6 and 1 year old. She hides inside doorways and jumps them when they walk down the hall, she corners them in the litterbox and won't let them out or if they try she attacks them. They are scared to death of her. Its gotten to the point that the 6 year old growls when she gets near her. I took Lindy to the vet and sure enough she had 2 teeth that needed to be pulled. That was yesterday. I was hoping that was the reason for the sudden meanness. Today, she is back to being mean. Any thoughts on what could be the problem or how to deal with it. Basically the 6 yr old has ruled the roost until 2 months ago. Oddly Lindy has never picked on the 3 yr old. Just the other 2.

It's a developed habit. Perhaps try a re-introduction?

If she just had teeth pulled, she probably smells different/like the vet hence the others not liking her.