Brushing your cats teeth is very important. Unlike dogs cats do not chew on things. So their teeth can get very bad as they get older (starting around 4). Cats typically don't like things done to them but if you introduce it very slowly like the video suggests it will eventually become accustomed to it. Another good way is starting with Kleenex  wrapped around your finger and act like you are scratching the side of the cats face, but try and get inside. Then after the cat finds that relaxing move up to the toothpaste and brush. The Kleenex will also take off some plaque, especially the bacteria.