I used to do that with my old cats, but after they passed and my parents “adopted” these new “Super Basement Cats” (see icanhascheeseburger.com) I tired to brush their teeth, and well, let’s just say, I used to also have ten fingers. As far as the health “risks” they are mainly to you, as in, if kitty no likky teeth brushing, kitty gonna bite. I have seen in PetsMart some toothpaste for cats that cost about as much as human paste, so I would just get some of that and some chainmaile gloves, or and full plate legging, seeing as those cats, when they drive those claws in, they don’t care what organs they hit! But ya, I have never had a problem, or even heard it was a problem.