Dentist left decay and a root on/in a root canal. He's swearing he did neither despite proof and wants to charge for any repairs due to "MY" error. He also fractured the tooth in two places and left me with microfractures in my jaw for months. An older root canal only has a quarter of the tooth left and is turning black but he wants to wait a few more YEARS to put a crown on it as it continues to flake off. I've had nothing but bad luck with dentists. Any ideas or should I give up?