The Dental Kong's grooves gently massage gums, clean teeth and help to reduce plaque.
The large and extra large sizes are bone shaped with hollow interiors designed for holding treats. As dogs try to remove the treats, their teeth and gums are effectively cleaned by the grooves (which can be used with dog toothpaste).
This kong is a great size - you can fit a lot into it - but of course with two large holes (instead of just one larger one and one tiny hole like the traditional kong), the dogs are a little faster getting out the goodies. This can hold more food than the XL and L regular kongs.