Crown rejection or bad crowns

Hello. I have had all of my molars except 1, root canaled. I lost a couple before I could get the crowns placed on them. Abt 10 years ago I had my first root canal and crown placed on #19. In the past 2 years I had #18 root canaled and crowned by a different dentist. From the day he put the temporary crown on #18, my gum was very sensitive and would not stop hurting. It was not red or swollen but it felt like it was. Even after he placed the permanent crown, it continued to hurt. So the dentist adjusted, filed, did little tweeks but nothing worked. One day abt a month later the pain moved to #19, which has never hurt or anything in 10 years and then I had an absess (abscess) and abt 2 weeks ago I was eating and #19 just came off with the post still inside the crown so I had to have the root tips removed. Is it possible that #18 was improperly placed and put too much pressure on #19? This same dentist also did a crown on #30 (but not the root canal) and 8 months later that one also just broke off at the gum line and the root tips also to be removed. About 8-9 months ago he did a crown on #14 and yesterday when I woke up, that tooth is now sore around the gum and I am very afraid that the same thing is going to happen. I have cried over this situation with my teeth and I just don't know what to do. I have an appointment with an oral surgeon next week to see about getting some implants because as of right now, I only have 1 bottom molar left and it is severely hindering the way I chew. What do I do? Is there anything that can be done to save #14. Could it be the dentist or am I just having an allergic reaction? He said that they are coming out because I waited to long to get the crowns. I could buy that but even when it was just the post and core, I never had any sensitivity or problems until he started putting crowns in my mouth. What do you think?

[Jerome Tsang, DDS]

There's alot going on right now so its a little hard to figure out.  I would say that your dentist should inform you prior to placing of the crown is the prognosis of the tooth is poor or fair only rather than good or excellent.  I normally inform my patients if I had a "bad" feeling about the longevity of the tooth prior to treatment.  Since the tooth needed a root canal, I assume its in pretty bad shape to begin with.  You could seek a second opinion with another dentist but I would guess it would be hard to guess what happened since the crowns are already done and he/she won't know what condition it was in prior to treatment.  Its hard to say.  It may be the dentist's work but it may also be the teeth in poor starting condition too.