Crown failed

Greetings -  at around the first of May 2010 dentist installed a temporary crown right side bottom molar while waiting for the permanent crown to arrive.  Temporary crown fell out while eating within a week of installation.  Dentist re-installed temporary, it fell out three days later.  

Permanent crown arrived but did not align properly so a second impression was made.  Since a temporary crown was installed and it too came loose.

When second permanent crown arrived, within two weeks it came loose.  Temporary crown was fitted with a stronger glue.  The fit did not feel proper, riding too high.  When I returned to the dentist, the assistant broke the second permanent crown, broke while being cleaned.  

Dentist decided to grind my tooth down a little more.  Dentist made a third impression, no temporary crown was installed.  

August 5, 2010 third permanent crown was installed.  Today, three days later it comes out while eating fruit snack.

I have been very patient and respectful with the dentist and staff.  I believe I need to locate a second dentist and start over again.  I will add, last year same dentist installed a crown on the other side with no problem.

Question:  Do you think the glue is defective or possible the curing lamp?  Do you suggest finding another dentist?  

I sent this earlier but the text was incomplete...Thanks...

[Jerome Tsang, DDS]

It depends on what the tooth looks like and how much tooth structure there is to provide support for a crown.  I do suggest going to another dentist though at this stage because it seems like its a problematic issue.  

[UninsuredScaredInPain]

I have a crown on a btm R molar that is at least 15yrs old. Over the last couple of yrs that tooth has become increasingly sensitive. A couple of weeks ago i had to start chewing on my L side only. And now i'm having a hard time doing even that. I dont know what's wrong & i dont know what to do because i have no insurance. Help, anyone??!!