Periapical granulomas were diagnosed as well-circumscribed periapical
radiolucency measuring less than 1.5 cm in diameter, periapical cysts were
characterized by well-defined periapical radiolucency with sclerotic borders
measuring greater than 1.5 cm, and periapical abscesses were characterized by
ill-defined periapical radiolucency with diffuse margins.
While bone resorption can occur in the presence of a periapical granuloma, it
is not a prerequisite for its formation. A periapical granuloma can develop in
response to pulp necrosis or infection without necessarily requiring bone
resorption to occur first. The granuloma can form as a reaction to the
inflammatory process, regardless of the state of the surrounding bone.