According to wikipedia,

Phantom pain sensations are described as perceptions that an individual experiences relating to a limb or an organ that is not physically part of the body.

Since I am no (medical) doctor, why am I interested in this topic? Well, this is because I have had some toothache that comes and goes for more than 25 years.

It all started when I was getting ready to study abroad. I was told that dental jobs are expensive in the U.S., so I wanted to have a bad tooth extracted. In the mid 1980s, there was a female dentist at Zhongshan University's Health Center, who graduated from a medical school in Beijing (as I was told). She was nice, and told me I should keep the bad tooth. She did root canal for me. However, the pain never truly went away, but was never unbearable. I waited until I had my first job with dental insurance. The dentist in Maryland said the root canal was not done properly, which made sense to me because I had pain ever since. So, he tried to re-do the root canal, and had to give up in the middle of it because the material used to fill one root was impossible to be removed. I suffered, and believed he was right (because I had sensation from that root).

Time went by quickly. Since then, I had a crown, and then a replacement of the crown. I joke about this tooth being the most expensive (man-made) part of my body, because each crown costs more than $500 and only covered partially by my dental insurances. Still, I am glad my Zhong Da dentist kept the tooth for me.

Then, a week ago, I had toothache and believed something was wrong with that (same) tooth). After trying to get rid of the pain myself (using my old tricks), I ended up in my dentist's office (because I will start to travel soon and didn't want to have toothache in a foreign country). He took a digital x-ray, and said he could not complain about the root canal done by my Zhong Da dentist. He also said he could not find anything wrong with my teeth, and therefore there was nothing he could do to get started. I was relieved.

Though the pain never went away, in fact, it often gets worse in the evening, I no longer worry too much about it. I also noticed some pain from other parts of my jaw/tooth. I decided to treat such toothache as headaches, since most of us get headaches for no apparent reasons, at least I do. Then, I heard about this phantom pain on NPR, and decided this is exactly what I have: The pain related to those roots that the root canal job covered never went away, though the roots were removed.