K.L.
Your first response from Mimi is your best clue. But, it is more than nutrition. If you want to get control of the situation, you need to learn how to manage the pH balance of your saliva. I would get some litmus paper and start testing my saliva on a regular basis. Nutrition does play a significant role in maintaining a healthy pH level, but so does our moods. Mental and emotionally stressed habits can also alter the pH of our saliva. And, when it comes to nutrition, it isn't always about what you are eating, but also about what you are able to absorb and metabolize. So, many people might actually improve their teeth more effectively by seeing a nutritionist and by learning to meditate. Dentists, in my experience, a great at fixing the problems once they occur, but I have only met a few dentists who actually provide the best advice for prevention, even via their staff.
Fluoride has actually been proven to be harmful to dental health, as well as your body's health. It is easy to find the truth about fluoride on the web these days. This is the first Google site that came up on a search: http://www.greaterthings.com/Lexicon/F/Fluoride.htm