Can I sue my dentist for malpractice for root canal failure, tooth lost and sinus infection?

I have been seeing the same dentist for 10+ years and that dentist had complete a root canal November 2005. I went into his practice due to severe pain and sinus infection and I found out that he and his partner had suddenly retired and most if not all the hygienist had left. The new dentist who took over the practice looked at my x-ray and said that whoever complete the root canal on #15 moral had not done the root canal properly and should have place cap over the moral based on standard practices. Then the new dentist informer me that I would need to see a dental surgeon for tooth removal and replacement along with sinus surgery. I then reminded the new dentist that the dentist he had purchased his practice from had completed the root canal and over the last 10 years twice a year visits had not notified me of the needed correction. Any suggestions on how to proceed. Is there malpractice? Was there an error in standard procedures during the procedure or during the next 14 to 18 follow ups?