How do I protect my dogs teeth from injury?

Yikes! I have never heard of this, can you link to a few of the reviews?

A dog cracking a tooth on a chew toy is exceptional. In the same way the people cracking a healthy tooth by chewing is exceptional. Certainly dogs and people crack teeth due to poor dental health or severe impact, but chewing? That's odd. Normal stuff like rawhide and kongs? Not going to crack a healthy tooth.

Given most dogs' general dental health, I'd say people griping on Amazon have a correlation/causation problem. (People griping on Amazon like to gripe, as well.) Just be reasonable, and don't give your dogs anything to chew that you wouldn't chew yourself (I mean because of hardness, not grossness). If you have multiple dogs or your dog will often be playing with other dogs, you should be thoughtful about what you give them to play with if they are really determined tuggers. We have several good-sized knotted rope bones, but I would take them away if they were dragging each other around the yard with them. I really prefer they tug with something that'll rip before it'll take a tooth out. One of my dogs lost a tooth because it was caught in one of the other dog's collars during a fight. It takes a lot of pressure to break a healthy tooth.

I would not give my dogs any of those three toys. Dogs don't need to chew on things with no give. I don't give them hooves or antlers or bones (among other reasons, I have concerns about contaminants in hard livestock discards) because I wouldn't trust my own teeth on them. Also, a dog can mostly clear a soft throat obstruction but could choke to death on a piece of any of those (or tear their esophagus).

One of my dogs has two cracked teeth (two slab fractures, one of which later broke to the root and had to be extracted). I have taken him to two board-certified veterinary dentists for specialty care, and what both of them have said is if you wouldn't whack yourself in the knee with it, don't give it to your dog to chew. That eliminates antlers, hooves and bones. But I think that rule is too lax, even, because I've heard of dogs aplenty cracking teeth on Nylabones and I guess I wouldn't mind hitting myself in the knee with one of those. I don't really trust those byproduct dried chews, either--their poop is always a gelatinous slimy mess afterward and I raw feed them with all kinds of weird things (put through a food grinder) and they always have beautiful poop, so something is definitely unhealthful about those dried chews. So, I have reluctantly concluded that the only thing I feel good about giving them is a filled Kong, which doesn't exactly involve chewing but does seem to satisfy the same urge. And a Kong is pure rubber and made in USA, so presumably pretty safe.

Our vet said anything too hard to dent with your thumbnail is too hard.

I have to wonder about some people and their reviews. Dogs, like humans will lose their baby teeth and teething is a big part of that process. What the dog will prefer to chew on will vary, but generally plastic or rubber toys will hold up well while they are pups. I have had really good luck with Nylabones in particular, but pretty much any such toy will do just fine. Dogs have pretty amazingly strong teeth - their bite is many times stronger than a humans and so the teeth are generally much sturdier. I imagine that chewing is very pleasurable for dogs - I have yet to meet one that didn't like to chew something at least sometimes. It can happen though, that they will weaken or chip a tooth - you should always supervise your dog with toys and judge how much and how hard they gnaw on something and judge accordingly.

by request, http://www.amazon.com/Nylabone-Durable-Dental-Dinosaur-Varies/product-reviews/B000084E6V/ref=cm_cr_dp_qt_hist_one?ie=UTF8&filterBy=addOneStar&showViewpoints=0 http://www.amazon.com/review/R1PF2QFB9S9LEI/ref=cm_srch_res_rtr_alt_19http://www.amazon.com/review/R10VE4MLMWFSID/ref=cm_srch_res_rtr_alt_13 examples. thanks!

Most dogs won't chew on bones once all the meat is gone if they have something else to chew on so I think bone and antler are too hard. My dog is a dedicated chewer and prefers things she can destroy utterly to things like bones which are not very satisfying. So I get her rawhides from Costco and that's a good balance of cost/ time to destruction for us. She also gets various softer toys and rubber balls when they're on sale or I feel generous but they generally die a swift death.