Sorry for your pain and troubles, hopefully it will resolve soon!
A short water fast of two days permanently resolved tooth pain I had after getting a filling close to the nerve.
I found testimonial in this and other videos helpful but keep in mind that 30BaD guidelines promotes no more than 3 days of water fasting on your own and only with supervision after that:
"Water only fasting in cases of acute illness or injury"
30BaD does not allow the promotion of unsupervised water only fasting for more than 3 days. Suggesting otherwise is dangerous to the health of our members and will not be supported here.
"While fasting for a day or two is rarely a problem if you are healthy, "it can be quite dangerous if you are not already eating a healthy diet, or if you’ve got liver or kidney problems, any kind of compromised immune system functioning, or are on medication -- even Tylenol," says Fuhrman, a family physician in Flemington, N.J..
As for helpful recommendations to help your long term health for teeth, you may find the tips in the 30BaD welcome wagon helpful: http://www.30bananasaday.com/profiles/blogs/30bad-banana-wagon-tour
To sum up- keep your fat intake at around 10% or below, eat daily greens in abundance, watch out for starches and oxalates, and eat enough calories.
I found this blog helpful for oral hygiene tips: http://health101.org/art_blog_dental_issues.htm
Clove oil put onto the tooth can help relieve pain temporarily.
Hope this helps!