Yes, regular bar soap apparently works. Because it cleanses the teeth properly without leaving a film that toothpaste leaves behind, which then allows for the teeth re-mineralise. You need supplement calcium, phosphate, magnesium, vitamin C etc in the diet too. I think diet is of upmost importance to this. Sugar can also hinder uptake of nutrients/minerals. So that's why I reckon it can contribute to tooth decay. not so much it's direct effect on teeth themselves, but inside the body and the damage it can cause. Teeth/gums are often a reflection of what's going on inside.

E.g. one round of antibiotics caused gum recession in my bottom teeth. They never grew back. So I do my best with my diet, my supplements and try and control it as best I can. I do ok, but if I let to of my dental hygeine regime, I am in trouble. I also found after those antibiotics that I now get ongoing calcus, which seems to get the inside of the two bottom teeth more than the others. I have to get rid of that nearly every 2 days. Never had that before the antibiotics!

I have tried the soap solution, but didn't find it really did much for me to be honest. But have heard it has for others and some have had really good results. I just went back the toothpaste after awhile because for some reason it suits me better.

It is bar soap, or tooth soap, but not liquid soap. Liquid soap does not work apparently and shouldn't be used.