I had this tooth filled 18 months ago, very deep filling, almost half the tooth I reckon. The dentist filled it slightly too high though, and my 'bite' hasn't been right since.
I've had no pain, the filling eventually just fell out last Friday, and to be honest my mouth has felt more comfortable without it.
New dentist reckons there's infection in there, but I can't feel anything. I'm inclined to wait and see what happens with the temporary filling she put in yesterday, then make my mind up before the appointment next month.
I don't think I could take, or afford, 3 hours of root canal/crown work though, so if it's bothering me by then, it's coming out.