Review (5/5): Recommended by a speech-language pathologist to help feeding skills
I don't know about this product being a "toy", but it was recommended by a speech-language pathologist (SLP) to help with some mechanical feeding problems. Our little one has had a hard time with textures in food, among other things.
It's a great teether, and has actually helped with feeding, too. I use one of those sippy-cup straps to attach it to the high chair, and he'll chew on it between bites. I could see using it as a toothbrush, which is probably its intended purpose, but for now, it's helping immensely with development issues. There seems to be something to chewing on it that causes the tongue and jaw to engage in ways that chewing on a baby spoon doesn't do. Plus, he seems to enjoy chewing on it and turning it over in his hands.
Sanitation/safety issues: I inspect it regularly to see if any of the "nubs" have been damaged or are breaking, but the entire item has remained intact for the few months we've been using it. Another plus is that the entire item is a one-piece mold, so it's very easily sterilized (there are no holes or hollow places for water or bacteria to hide). I haven't placed it in the dishwasher, but I could see it going in with those rubber baby spoons and faring well. I usually just handwash it w/a good soap and sometimes a very diluted bleach solution w/a LOT of rinsing, like other hard plastic toys. The rubber head has some give but is not so soft that it bends, and the handle is very firm. He has NOT placed it so far back in his mouth that he could gag on it, but like anything else w/young children, it's a possibility and not an item that I would allow him to use w/o direct supervision or where I couldn't easily grab it (i.e. in a car seat).