Dentists are in every suburb. Teeth issues are more common than anything it seems regardless of dietary choices. My teeth are chipped, antibiotic stained and half ground from decades of bruxism. Im surprised Ive got any left. My Dad didnt when he was my age. My Mum has a mouth full of mercury.
Early nights help teeth health. As does avoiding a dry mouth. Same with low stress lifestyles.
Stop eating anything that makes your tooth hurt.
Concentrate on soft and/or juicy foods such as bananas, mangoes, melons, plain greens (wash well from sand), but NOT salad with dressing, acid fruit, non-blended dates, nuts, sour and hard apples, grainy pears.
Do plain saliva swishing as much as you possibly can - seek out every opportunity.
Saliva repairs the teeth.
So there will be 2 parts in your program: stop damaging and irritating your tooth, do saliva swishing to repair the tooth.
I've been really working on this matter as well... So far have only found a way to prevent further decay (or so I hope), but haven't found a way to heal the cavity yet. I'm hoping as the acid in my body detoxes out completely over the next year (your probably in the same situation) that at a certain point once the acid is out my blood will be so alkaline that my teeth will start to remineralize again.
Whatever you do make sure your getting enough minerals, especially calcium, magnesium, and silica... Eat tons of greens and a variety. (I saw the most tooth decay when I was getting hardly any calcium and was on a high fat diet...)
I experienced this, it eventually went away!