Endodontic disease occurs in the white circles,
NICO almost never does.

A mandible with ischemic osteonecrosis, profusely riddled with brown,
mushy, diseased marrow with scattered hollow spaces. White circles show the
area affected by dental abscesses and periapical granulomas. Almost all of the
ischemic disease is outside this area and would not be picked up in a periapical
or endodontic biopsy sample.