Formula of dentist: Na2EDTA 17g Aqua purificata AD 100ml neutralize with NaOH 5N to pH 7

The solubility of Disodium EDTA is 1 in 10 so about 10% but this of tetrasodium EDTA is much higher. The latter is not between the Bassron products. Adding NaOH to pH = 10.5 would provide you with Na4EDTA. You should ask your dentist about the source of his formula and possibly the possibility to reduce the amount of Na2EDTA.

I am also asking myself whether this solution should be sterile. And this to avoid infections. But in this hypertonic solution, germ growth is unlikely to be possible. In any case, use freshly cooked water and wrap in a sterilized bottle. I would confine myself to a small volume on delivery.