I had a similar experience using nascent iodine on some tooth pain I had last night. I put a drop on the few lower front teeth that felt like they were hurting and also swished some colloidal silver. Within 30min pain was gone and hasn't come back.
I have been using iodine to cure cavities for about 40 years. It works great. Organic iodine from the health food store is probably best but I've mostly used the ordinary stuff from the drugstore.
If you have active cavities and perhaps toothache as well, put 10 or 12 drops in a small amount of warm water (about a mouthful) and swish it around your mouth for 30 seconds or so. Then spit it out. You will notice most of the colour is gone. Do this many times throughout the day.
Soon your toothache will stop and you'll see recalcification on your teeth. Don't stop using the iodine but you will find you can cut back a lot. I usually now use a couple of drops twice a week.
If you have big cavities you should get them fixed when you can afford it. Otherwise, if you forget your iodine for a couple of weeks the cavities will start to bother you again.
I had a dentist remark that I had "many small cavities that have healed over" which surprised him.
I did this iodine treatment for about 25 years, then stopped for years to see what would happen (no problems) and have now started again once a week, two drops.
Don't swallow the iodine and water mixture! Spit it out! Don't stop using it unless you get large cavities fixed!
The only new cavity I've had in more than 40 years is one that was deep inside a gum. I guess the iodine couldn't reach it.