Our member, Haitham, needs advice. Any ideas?

A message from haitham to all members of Endodontics on WebDental!

iam egyptian dentist&also very difficult case hahaha
this is my story i have upper left 7 which had 2 re-endo treatment the
problem everytime pain with percussion&pain without stimulus the
diagnosis was periapical lesion but there is no pus no swelling in x-ray
only widening on periodontal membrane space with slight radiolucency
periapically some professors say it is 2ry apical peridontits

i feel the problem in palatal canal which enlarged to size 110 apex become so large

i did irrigation with sodium hypochloride- hydrogen peroxide -saline
i put ca hydroxide periapically using file&cone there is mild relief but after time pain come back
i use dermatic cream containg steroid&antibiotic also mild releif
but pain happen again really i get upset i dont know what to do i feel
that my teeth didnt accept endodontic treatment as i have to extract
upper 6 before for persistant infection too
there is dentist advising me to make mix from clindamycin&saline &apply it apically
iam afraid of persistant bacterial action
do i have to take biopsy is there any clinical guide to take it in the right way
any idea do u have?