Ouch! Sounds awful, and what really sounds awful is the stuff that is supposed to be helping you causes MORE tartar and permanent toothwork staining. I personally do not know about zapping I have never tried it so I can't help you with that,,,sorry.
I did have a tooth that was giving me quite a bit of pain however a couple of months ago (Ithink). Anyhow I mixed up some Miracle-Mineral-Supplement and took this solution, took a syringe and got some in that and squirted it in the area that was hurting. I did that 3 times. I then rinsed my mouth with and swished it all around with the ramainder. by the next morning the pain had subsided a lot. I did this for about a week straight right before bed. The pain left and it has not returned. You may want to try the Miracle-Mineral-Supplement it is some powerful stuff.