You have to get the size and chew strength to suit a given dog. A dog should not be able to chew through them -- that means they are either too small or are not hard enough. There are really rock hard plastic ones that only mega-chewers can chew through. If you have one of those then it means they have to be thrown out sooner. Same with Kongs. My partner and I have a hard chewer alsatian and he only gets the hardest Kong, the black ones. Takes him ages to chew through those.

It would be dangerous to give the softer ones to a dog that chews them into chunks. They can definitely cause a fatal intestinal obstruction like any other undigestible object be it fabric, string, pieces of rug, antler, large pieces of rawhide, leather, piece of clothing etc.

There are many chew items on the market for tough chewers.