@burcidi-- I've been using natural toothpaste for the past year and I really like it. After reading your comment, I check the ingredients and it appears to be mainly silica and calcium and some other natural plant extracts for flavor and to soothe the mouth.
I believe the calcium basically does the same thing as fluoride, it makes the enamel stronger and I guess the silica is kind of like baking soda that people have traditionally used to clean teeth. It says that silica cleans the teeth, polishes and whitens it as well. So I don't see why it wouldn't protect against gingivitis.
I'm very happy with my toothpaste, I honestly can't see any difference from the regular toothpastes other than the fact that it is all natural. I recommend it.