Which lesion displays an ill-defined border?
Ill-Defined Borders
Blending Border: A blending border is a gradual, often wide zone of transition between the adjacent normal bone trabeculae and the abnormal appearing trabeculae of the lesion. The focus of this observation is on the trabeculae and not on the radiolucent marrow spaces.
Examples of conditions with this type of margin are sclerosing osteitis and fibrous dysplasia.
Oral radiology White and Pharaoh; 7th ed. Page no 276,277
Periapical cyst
Sclerosing osteitis
Soft tissue capsule
Multiple myeloma