Thank you very much for your answers.
Regarding tooth #14 i wouldn't be surprised if the root canal specialist say he did everything right and everything is ok, but wouldn't he see ( and tell me ) if there is decay and a root fracture, if there is one ? He took an x ray when I went for a follow up visit.
And couldn't the general dentist see on the x ray she took of the tooth #31, the recurring decay underneath the filling ?
It shouldn't be a sinus connection if the tooth #5 gets extracted ? or there is always a possibility for one with upper teeth ? And if there is a fracture of the root system ( tooth #14 ) plus the tooth is in a sinus or very close to it, how difficult is the extraction ? ( I was thinking to have that tooth extracted before the re treatment, but then I didn't know all of the bad things about root canal, so I thought I'll save the tooth ).