We have no decay issues at all. I do not believe that tooth brushing prevents decay. I have relatives who brush regularly whose teeth are a mess. I never brush my teeth, nor do my children, and we all have glowing white, tartar-less, thickly enameled teeth. I had a cavity years ago that healed after I quit brushing and started eating lots of fat and animal-derived foods. I also took a lot of supplements to keep myself healthy, but have not needed to take them since quitting grain and dairy. Now, my food is adequate.
I think health of every part of the human body comes from nutrition primarily, and decaying bones in the mouth signals decaying bones elsewhere as well. Why are those bones decaying? My experience has been that we are what we eat, so nutritious food in-keeping with evolutionary practice, is what makes our bones strong- in the mouth and everywhere else, too. Our food provides the building blocks of our cellular development, and it takes approx. seven years to renew the cellular make-up of the human body. In other words, your body is presently composed of cells made from foods you have eaten up to seven years ago. If you want strong cells, you have to eat foods that provide strong and robust constituents to build those cells. Our bodes are amazing, and they even take substitutes when the real stuff isn't available, but the result is cells that are not as strong as they would be if the real stuff were.
I know my perspective is not popular, but my experience is my evidence. I have also researched this extensively and continue to come to the same conclusion. Pick your teeth if things are stuck in between, but brushing off good bacteria and eating non-evolutionary foods, is just not going to bring about strong bodies. Your teeth will tell you if you're not eating well enough to build strong cells. They are a window into our body composition. If they are decaying, there is a serious underlying deficiency of excellent food.
ETA: Tooth decay may be normal, and many/most people accept it because it so common, but it is not a given. My own body has shown that even when it has occurred due to inadequate nutrition, proper nutrition can and does heal it. Also, tooth decay is traced back to peoples who ate grain and/or were starving. Grain depletes minerals from the body, so even an otherwise adequate diet can be rendered inadequate by eating it. Healthy peoples did not have tooth decay, and we don't have to have it either- especially given the abundance of good foods available to us.
Edited by PreggieUBA2C - 1/1/11 at 5:42pm