Holy carp… I have recently been in agony due to a broken tooth with a nerve that is practically exposed. Last night I took six ibuprofen capsules, two codeine tablets, and held a cotton bud soaked in toothache drops (ethanol/phenol/benzocaine) on the exposed centre of the tooth, followed by another one soaked in clove oil just to get a few hours sleep.
Today I went to the doctor, and she gave me a small vial of magnesium salts. I waited until the pain was almost unbearable again, dissolved less than a teaspoon of this substance in lukewarm water and swirled it around in my mouth for about five minutes. Less than ten minutes later, the pain was almost completely gone and so far has not returned. She said she only had to do this twice for her own tooth and the pain never came back.
This shit is freaking awesome and I recommend it to anyone with tooth pain.