And more agony

Over the past few weeks one of my back top teeth has become increasingly sensitive to hot and cold foods, to the point at which a misplaced drop of ice-cream now has me writhing.
So, as we're in Streethay for a week or so, I decided to try pot-luck with one of Lichfield's many dentists. The dentist was a friendly young woman (why are so many dentists these days women?) and said it was simply a loose filling that needed replacing. She would do it there and then. Great.
Well, three doses of local anaesthetic later - one of them so painful it made me let out an involuntary curse - and she had to admit defeat. Six hours later and my mouth has finally more or less resumed its normal size and shape and I can drink without drooling.
Problem is, apparently, that the root may be dying. I would have thought that made it less sensitive but seemingly not. A week of smearing layers of Sensodyne on it might help, she reckoned, but most likely it would have to come out. I'm not sure I can spare many more of them!