I caught part of a newscast on the radio and thought I heard a correlation between root canal and depression...that fiddling with the nerves in the upper teeth can cause depression ... neurotransmitter interruption or something...could this be possible?

I've never heard of that.. your teeth are no way connected to neurotransmitters. Now if your teeth are rotting out of your head and you need a lot of expensive dental work, that certainly cause a little distress.

I know from expience that when I had a root canal done on any tooth it did make my whole mouth react to the sorness. An infected tooth affects the whole mouth and when you can't eat anything but baby foods, that could depress anyone!
Seriously, Any work done, the more the worse teh affect to all your other teeth, I think. And this uncomfortable state can be depressing.

The good news "This too shall pass away!"

My uncle became paralyzed from, believe it or not, a neglected abcessed tooth...apparently the "poison" traveled some sort of route to his brain and caused paralysis which then necessitated brain surgery...therefore, I thought there might be some true validity between root canal and depression... does anyone know for sure that it couldn't cause a biological depression?