I have a theory about Reach toothbrushes. They're the ones that have an elbow bend so you can "reach your back teeth" easier. My theory is that they were originally developed so that the head of your toothbrush wouldn't touch your counter when you set them down. You keep the part you put in your mouth away from all the beard trimmings and mystery hairs on the counter and it's a bit more sanitary. Then, in my theoretical world, the marketing crew at Reach heard about it and they didn't want toothbrushes and filth in the same marketing pitch, so they invented this "back teeth" thing. It's weak, as theories go, but it's all I have to go on right now.