This study correlated the radiographic findings and scanning electron microscopy (SEM) images of external apical resorption (EAR) in teeth with periapical lesions. Standard radiographs were taken from 45 teeth with periapical lesions before their extraction. Using a radiographic examination, the root apex of each tooth was classified according to the EAR into the following categories: radiographic external apical resorption (REAR) absent, superficial and deep. The apical root surface was also examined with SEM. Photomicrographs of EARs were classified as periforaminal (PEAR) and foraminal (FEAR) in three degrees: 0, 1 and 2. REAR was present in 72.5% of cases, of which 20% were deep. Based upon SEM analysis, PEAR and FEAR occurred in 75.6% and 66.7% of cases respectively; 51.2% and 59% respectively, of these teeth received a score of 2. Only 15.4% of the specimens were unaffected by EAR.
When teeth with periapical lesions were examined for EAR with both radiography and by SEM, there was no correlation between the findings.