I am having some problems with tooth No 25. Image 25_A explains what is the problem. The photo was done in December 2016, since then the tooth got even more sensitive, i.e. experiences a lot of pain if exposed to any heat or cold (tea or cold water).

I have visited one dentist in December and she wanted to kill the tooth immediately; she then changed her mind and said we should wait and see what happens, which is code for let’s let it die on it’s own.
Visited another one in January. She wasn’t sure also what to do — to open up the tooth or to wait.

The filling is quite big and it seems the nerve is swollen on is squeezed against the filling.
I would ideally like to save the tooth rather than killing it of the bat. What should be done?

Thank you