I think that a diet low in processed foods, sugars, and salt and high in vegetables, whole grains, and protein is the key to a variety of health issues. If you're eating a lot of soy products and that sort of processed food, try switching up some of your recipes and using lentils, kidney beans, white beans, any beans instead of the "fake" meat products. Dried beans are always best, but frozen and canned are fine to. I've been vegan and vegetarian for almost ten years now, and I've had minimal tooth problems. When I was a child and eating meat, I had at least 6 cavities filled and two root canals. But that's just me. Some people are meant to eat meat, and some people aren't. You gotta listen to your body. More important than if you eat meat or not, is what comes along with the foods you're eating- what hormones, chemicals, etc. Factory farmed meat has hormones and all sorts of nasty things, and that meat was fed on a very unhealthy, low-in-nutrition diet, so that meat isn't very good. Animals that eat a well balanced, wild menu will make for more nutritious meat.
I try to eat a pretty well-balanced meal, with the exception of a candy bar every couple days and some processed, enriched, non-nutritious grains thrown in to the mix. I try to eat as much dark leafy greens as is seasonally appropriate, and I have root vegetables a few times a week (as is seasonally appropriate). My husband has a very physically taxing job, so I make sure to have some protein in every meal. We get eggs from the free-range chickens our Amish neighbors keep (only $2/dz!) so I supplement the variety of legumes we consume with that. I make sure to have rice or some grain with the beans on most occasions, to make for a complete protein. Red quinoa is also said to be a complete protein.
Now, the diet I'm describing is not realistic for most people. I don't have a child yet, and I prioritize healthy eating over many other things.
Oh, and I do know a few people who eat very, very strictly non-processed diets (like raw food diet) and don't brush their teeth. Since I do eat candy bars and processed grains, I do brush my teeth with non-fluoride, non-SLS tea tree toothpaste.