I’ve heard that putting teeth that have been knocked out into a cup of milk will let the doctor/dentist put it back into your mouth. Is cow milk the best for this, or can it be from any animal? (I’m guessing almond milk is no good?) Don’t need answer fast. 
It’s just to prevent the osmotic fuck up that will ensue if you put it in straight water. Any animal milk will do. Plant milks are probably fine as well, though I’m not going to do a full comparison of dissolved ions or do the necessary experiments to see what ranges are safe for this purpose.
But what about the SCIENCE? 
So would saline work? Or do you need a lot of different types of ions?
If research dentists haven’t bothered doing this so far I’m certainly not going to do with it. I’m finding it hard enough getting sufficient numbers of knocked out teeth for my current set of experiments.
I think saline would be fine, but it’s a long time since I actually learned about osmosis. The NHS doesn’t mention that option, but that is probably because people don’t generally have medical saline solution lying around.