Without any details about the price of the procedure and the type of procedure I can only provide a general answer. Assuming that the dentist suggested an unnecessary procedure yet performed it correctly, your claim against the doctor may be more of a fraud claim than a dental malpractice claim. If the dentist performed a procedure and fell below the standard of care in the performance of the procedure, then you may have a malpractice claim as well.
Could be. The standard of care is the measuring stick for a lawsuit. If you did not have the physical findings or symptoms sufficient to qualify you for the procedure, it is possible that the standard of care would forbid its use.
I will say, however, that even "ridiculously" priced procedures in the dental world are usually not enough of a damage model to justify the massive expense of malpractice litigation. These cases cost tens of thousands to pursue. You would not want to spend four times the amount of your settlement on the case itself.