I'm not a big fan of them, as Darwin can have a sensitive stomach.
Our Vet recommended them at our last visit. I told him they're full of fat/cr**
He respects my views as he knows how closely I keep and eye on Darwin's weight
but recommends that I find something that a dog can chew on to help keep their teeth clean.
We've tried Stag Bars but Darwin is scared of the noise they make when he drops them on the wooden floor
The veg based tooth brushes etc are OK, but only as an once a week treat.
I'm not keen on the on the idea of natural chews such pizzles and ostrich tendons as I think they may be too rich.