Here is something I was unaware of, that diet could potentially reverse tooth decay. Changing your diet is a lot less expensive than dental work.
Reversing Tooth Decay
When enamel is poorly formed and the diet isn't adequate, enamel dissolves and decay sets in. Tooth decay is an opportunistic infection that takes advantage of poorly built or maintained teeth. If the diet remains inadequate, the tooth has to be filled or removed, or the person risks more serious complications.
Fortunately, a decaying or broken tooth has the ability to heal itself. Pulp contains cells called odontoblasts, which form new dentin if the diet is good. Here's what Dr. Edward Mellanby had to say about his wife's research on the subject. This is taken from Nutrition and Disease:
Since the days of John Hunter it has been known that when the enamel and dentine are injured by attrition or caries, teeth do not remain passive but respond to the injury by producing a reaction of the odontoblasts in the dental pulp in an area generally corresponding to the damaged tissue and resulting in a laying down of what is known as secondary dentine. In 1922 M. Mellanby proceeded to investigate this phenomenon under varying nutritional conditions and found that she could control the secondary dentine laid down in the teeth of animals as a reaction to attrition both in quality and quantity, independently of the original structure of the tooth. Thus, when a diet of high calcifying qualities, ie., one rich in vitamin D, calcium and phosphorus was given to the dogs during the period of attrition, the new secondary dentine laid down was abundant and well formed whether the original structure of the teeth was good or bad. On the other hand, a diet rich in cereals and poor in vitamin D resulted in the production of secondary dentine either small in amount or poorly calcified, and this happened even if the primary dentine was well formed.
Also, what is up with phytic acid, and should it be avoided (in the diet) in cases other than when trying to repair tooth decay?