From what I've been told, chewing also helps the baby teeth fall out so that the new ones can grow in. My s/o's mom has a tiny toy poodle and had to have several of her baby teeth yanked out by the vet when she got her spayed, because her mouth was so little that she was having trouble finding things small enough for her to chew on.
When my guy was teething, we gave him nylabones (the brown ones that look kinda like regular bones and the cornstarch ones. He doesn't like the cornstarch ones much, but they lasted longer, and at that stage, he was willing to chew on anything). Occaisonally he would have a pig ear, bully stick or rawhide to chew on, but the cornstarch bones seemed to be the ones that lasted longest and the ones he worked on most. He also had his little rope toy to chew on, and still loves to chew on it.
We bought a "chilly bone" from Petco, but he was never too interested. It's basically a fabric bone that absorbs water really well. So you freeze it, and it's esentially a doggy version of a baby's teething ring. Ein didn't care for his, but he's always liked chewing on ice cubes, so we gave him extras of those while he was teething, to help him feel better.
As long as you provide plenty of things to chew on that are reasonably hard, I don't think it matters much *what* it is that you give him. Definitely make sure there is plenty of chew stuff around, though, so that the pup doesn't start chewing on furniture/etc to try and make the teethies feel better.