It's a myth that wet food is worse for teeth than dry food. Cats don't chew very much, so not a lot of food is making contact with their teeth anyway. Unless a cat is eating a raw diet and gnawing on bones and sinew, the best way to prevent dental problems is to brush teeth daily.
Hmmm. I hadn't heard that one. But it sounds like something "the dry food" people might say.
I think it's strictly carbs that cause tooth decay, like grain for instance. After all, carbs are converted during digestion to glucose which is sugar.
In another article written by a dentist, he says at first that sugar does not cause cavities, but then later on states refined carbs DO cause cavities. Of course white sugar is a refined carb.