That was a myth that was started by the grain companies to try and get folks to
buy their product. Their thought was the wet food (mostly pâté) was not abrasive enough to keep teeth clean,,like the dry does. In reality, the crunching of dry kinda explodes off the tips and doesn't clean like they say it did. Reality is, neither one is bad or good in that aspect. The only thing that really is "good" for their teeth is something with whole meat muscle tissue (I.e. a piece of fresh chicken etc).
A good quality dry food is not bad, as long as your cat drinks enough water to not get dehydrated. Some cats simply do not drink enough, while others do. In the wild, a cat gets over 95% of its hydration from the food it eats.
I wish I could use at least some dry food, as it is convenient, but the health issues of one of the cats prevents it. It is easy to spot when a cat isn't getting enough water...especially when you scoop the litter box. A strong urine smell, and small puddle clumps are the easiest signs to spot.
So not saying a wet food diet is "best" for every cat, it just happens to be what works the best in my home
