Dental malpractice or a waste of people´s time and money?

I went to a dentist in January and had a full set of xrays completed. I complained of pain and problems with an area of my mouth. I returned to this dentist 4 times to address the same area and he attempted to fix the cavities several times. Finally after 9 months, I went to another dentist with a copy of the xrays taken in January by the first dentist. The new dentist was appalled at the level of decay and promptly informed me I would require at least 3 crowns on the teeth the former dentist worked on. I have since had to take a line of credit to pay the thousands of dollars for the work my insurance doesn´t cover. I believe this could have all been avoided in January when the xrays were taken. I just want the first dentist to pay for the repairs I´ve had to have. Is that possible?