Slide 2:
There is no evidence that necrotic pulp tissue per se can elicit periapical inflammation, in the absence of bacteria.
Slide 3:
78 monkey teeth
with
aseptically necrotized pulps 26 bacteria-free 52 bacteria infected 7 months Apical periodontitis No apical inflammation Moller & Fabricius 1981
Slide 4:
Periapical responses to pulpal infection
Slide 5:
Bacterial products IL-1 IL-2 MF Th B Periapical inflammation and bone destruction MHC-II IL-1, IL-6
TNFα
PGE Ag
Periradicular lesions - barrier :
products Microbial Periradicular lesions - barrier Complement Granulomatous
tissue Defence
elements PMNs Microorganisms Very few endodontopathogens can advance through the barrier.
Extraradicular microorganisms :
Abscessed AP
Actinomyces spp, Propionibacterium propionicum
Infected radicular cysts
Infected material displaced into the periapical tissues Extraradicular microorganisms Possible factor in the failure of the endodontic therapy.