interradicular osseous defect

in·ter·ra·dic·u·lar os·se·ous de·fect

(intĕr-ră-dikyū-lăr osē-ŭs dēfekt)
Bony deformities resulting from periodontal disease seen in bone between root furcation areas of teeth.

interradicular osseous defect (os´-ēəs),

n the radiographic evidence of a discontinuity in the bony image in the area between the roots of a multirooted tooth.