Sorry to hear you are dealing with tooth pain. Salt water will not help with tooth pain. You will need to contact a dentist to find out what is causing the pain, and what can be done to relieve it. Best of luck!

Salt water is soothing and antibacterial to issues with the gums or other soft tissues of the mouth. It has little or no effect on hard tooth structure.

Probably it’s the warm part of the warm saltwater that works- the salt part acts as a means to gently clean soft tissue wounds - remember salty like teardrops not brine