What is a good toy for an active old dog with bad teeth?

My old dog (a english staffy) used to chew up a tennis ball in 5 seconds flat! (she still ran around like crazy and played like a puppy but she was 9) so we got her a kong, you can put treats inside them, they are rubber (soft, yet still strong so they can't chew it to pieces)! theyre really good, kind of expensive (i paid $25 au) depending where you shop.