Confusion related to non-isurance covered dental treatment and tax deduction

I have been going in and out of the dental office for the past year due to multiple complications. I am missing a lot of teeth, so apparently my jaw has "sunk" which causes me chronic pain, not just in the jaw but in my neck as well.

The dentist laid out a 14-month plan with me which includes implants, crowns, a bridge and gradually lifting the jaw.
All this is costing me close to 2 million yen. I already paid close to 800,000 this year.

The dentist says it can be deducted by tax because it is a reconstruction for health improvement, but I also read that stuff like implants are considered purely cosmetic and “excessive" meaning that they cannot be deducted.

So how exactly do I prove that the implants were part of a bigger plan to treat chronic jaw pain?
Do I attach a note from the dentist or what is the correct procedure?

by Additional_Bear8735