Responses on this thread have proven that there really isn't a "perfect" chew. Anything hard can break teeth. Real bones can splinter, things like hooves and ears can stain, rawhide can choke, big pieces of anything can gum up their insides.
My SIL is a vet and she still uses rawhide.
One of my current dogs eats any sort of loose fabric so even though she's cold in winter she can't have a sweater on unattended nor any blankets. Thankfully most of my dogs haven't been big chewers, so Nylabone still works for me since they don't work at it for too long or too hard. A single one will last 6 months if not more.
My SIL is a vet and she still uses rawhide.
One of my current dogs eats any sort of loose fabric so even though she's cold in winter she can't have a sweater on unattended nor any blankets. Thankfully most of my dogs haven't been big chewers, so Nylabone still works for me since they don't work at it for too long or too hard. A single one will last 6 months if not more.