I have a bit of a crowded mouth — small mouth relative to jaw size — so it’s very difficult for me to scrub the sides of the rear molars. The Sulcabrush, which I’ve used for about 15 years, is still the only brush I’ve used that adequately cleans the far surface of my rear molars. The Sulcabrush works because it’s thin, has a couple of good angles to it, and the bristles are medium stiffness, so they don’t crap out very quickly. It’s a pain flossing back there. Flosspicks (even the Reach flosser) are a little too big for my mouth. I’ve had some success with Reach toothbrushes and some Oral-B’s with the stiffer bunch of bristles at the tip, but after about a week, these edge bristles splay and become less effective.
The Sulcabrush keeps working again and again. Since the Sulcabrush’s bristle bundle is pointed, I think the total angle is a little more than if it were flat, and better than what I’ve experienced with average toothbrushes. I’ve found the pointed end lets me cover more of the molar sides (chewing surface is easily handled by regular toothbrushes). The downsides are that it’s essentially another toothbrush to use and it’s not particularly versatile — i.e. I don’t like using it to brush the rest of my teeth, because of the small area it targets and the stiffness of the bristles. However, I’m very happy with how it cleans the crud off the rearmost molars.