It is a myth that dogs need to eat dry kibble to clean their teeth. A high quality canned food will not cause any more tartar build up than a high quality dry food. If this theory is true, then as humans all we'd need to do is eat a few crackers a day and we'd have no need to brush our teeth.
The thing is, starches cause plaque buildup. Low quality foods are filled with sugars, corn, and other starches. This plaque will then turn to tartar, which is the hardened substance you see on some dogs' teeth. Eventually, if this tartar is not removed, it will turn to infection. It's caused by starches... not textures of foods.
My dogs get raw bones to chew on which removes the tartar, and I also brush their teeth.