Agree with Jessi. I've never seen so many obsese, dandruffy cats as the ones who eat dry only.
Hard food has nothing to do with healthy teeth and a dry diet is about the most unnatural thing that cats - obligate carnivores - can eat.
I've had cats all my life, never had a fat one and they all had good teeth and lived for between 17 and 20 years. Never had a neutered male with blockages either. They all ate canned all their lives with a little dry for snacking.
I never brushed their teeth either.