I'm not sure what's happening. Couldn't find any related studies. But i have seen in couple friends already if you have teeth sensitivity and teeth that go bad frequently you might have problem with upper back. This leads to too much urination. Especially if you don't drink a lot. Kidneys need sodium for functioning. I can only speculate that kidneys for some reason are forced to lose sodium with urine and as result you'll have tooth sensitivity or even heart problems. My observation showed that upper back backward bend helps to eliminate that. And this might be the result of bad posture. But definitely i don't have good understanding what's happening, because I'm not a doc. Just try to bend like for gymnastics bridge (yoga wheel can help or sturdy park bench) and see yourself. It will take just couple days to show results,