What is the difference between boar bristles and reinforced boar bristles on a hair brush?

Also, what type of brush and bristles do you prefer to use?What is the difference between boar bristles and reinforced boar bristles on a hair brush?
It sounds to me like reinforced bristles have some plastic involved. I can't help any more, I'm afraid, I don't use a hair brush! My hair is just a curly mess...