I use the crayola brand brushes. They have a yellow handle
and a good bristle head. They are kind of pricey for elementary
brushes but they last a long time. And they come in sizes 2-12,
round. I have never had a problem with the bristles falling out
or anything. I only have the problem of kids "experimenting"
and trashing/tangling the bristles. When that happens, I turn
the brush into a chinese calligraphy brush by cutting a sharp
angle in the bristles (looks like a calligraphy nib).
I ordered the Crayola brushes this year (I'm at a new school)
from either Sax or Nasco, I don't remember. It was in a bulk
pack, with 24 of each size, for about $150 or so, I can't