My dentist did a gold crown on a molar because the existing crown was damaged. I was having sinus and jaw pain at the time. The pain didn't go away with antibiotics( on the side of the crowned tooth. ) My primary Dr had me do a cat scan etc, but that was clear. He told me to go back to my Dentist to check for TMJ disorder. I went back to my dentist and it turned out I needed a root canal right away. So he drilled a big whole in that brand new gold crown and did the root canal.
QUESTION:
Shouldn't he have done something to check for the need for a root canal BEFORE putting the gold crown on?? Not to mention the cost of the cat scan and time off from work to do it.

Yep! Dentists are funny that way sometimes. One thing to keep well in mind when going to the dentist's office is that they are human beings and carry all the emotional baggage that all human beings do. Higher education, unfortunately, doesn't provide 100% imunity against inferiority complexes, bigotry, bad moods, or even sadism.

Here are some things not to do at the Dentist's office in order to minimize risk of ticking him or her off:

1. If a foreigner don't ask where he or she is from. Treat them as if you don't notice.
Nobody likes to be reminded that they stand out that way.

2. Don't speak loudly in the waiting room-sound carries and it might break his concentration-or simply provoke an involuntary territorial protection tendency.

3. Don't become overly familiar. They might see it as an insult based on your lower opinion of them within the doctoral hierarchy. If the dentist is female, she might take it as a come on or as male chauvinism and get her point across with the drill.

4. Treat assistants with kid gloves. Otherwise the assistant might imagine an insult, begin to pout, and the dentist, who might also be her good friend, might pass judgment -- get angry and insult you while you are under the drill as happened to me.

5. If you feel the least bit uncomfortable immediately go to another dentist. Otherwise you are playing Russian Roulette.

BTW
I think you have a good case for a malpractice lawsuite