Internal apical resorption and its correlation with the type of apical lesion

To determine the presence of various periapical pathologies and their association with the presence and extent of internal apical inflammatory root resorption in human teeth.

A total of 75 root apices from extracted teeth with periapical lesions were examined. Semi-serial sections of soft tissue lesions were stained with HE. The lesions were classified as non-cystic or cystic, and according to the degree of abscess severity: 0, 1, 2 or 3. The apices were reduced to 3 mm in length and longitudinally cut so that the internal aspect could be analyzed under scanning electron microscopy (SEM). Internal root resorption was also classified as 0, 1, 2 or 3 according to the extent of the resorbed area. Additionally, six vital teeth were used as a control.

Non-cystic lesions with severe abscesses were the most common finding (70.7%), while 20% of the lesions were cystic (4% little or no abscess; 16% severe abscesses). Non-cystic lesions with little or no abscess comprised 9.3% of the sample. Of the root canals containing periapical lesions, 48% had internal apical resorption in more than half of the area, while 25.3% of the sample had no internal resorption. Resorption degree 1 was identified in 12% of the cases, and 14.7% showed resorption degree 2. The control group displayed significantly less internal resorption than the test groups.

Most periapical lesions (86.7%), whether cystic (16.0%) or non-cystic (70.7%), showed large collections of acute inflammatory cells. Apical internal resorption was present in 74.7% of roots and was associated with periapical lesions. There was no correlation between internal apical resorption and the histological diagnosis of the lesions.