Accuracy of chemically created periapical lesion measurements using limited cone beam computed tomography

The aim was to assess the accuracy and reproducibility of measurements of chemically created periapical lesions using limited cone beam CT.

Periapical lesions were chemically created in 18 mandibular cadaver teeth. Mandibles were dissected buccolingually using a bone-cutting burr. Diameters and depths were measured directly in the cross-sectional slices using a precision digital caliper. The cross-sectional slices were then embedded in wax, and cone beam CT images were acquired using a NewTom 3G Plus scanner with both 6 inch and 9 inch fields of view (FOVs). Two oral radiologists measured the diameter and depth of periapical lesions on the cross-sectional images using the built-in measurement tools. Measurements were repeated after a 1 week interval. Inter- and intraobserver agreement was calculated by ANOVA. Regression analysis was used to test the correlation between the cone beam CT and digital caliper measurements.

No significant differences were found in diameter or depth measurements between or within observers or between 6 inch and 9 inch FOV images. Regression analysis of diameter and depth measurements made by direct caliper versus 6 inch or 9 inch FOV images revealed a high regression coefficient (for diameter: 6 inch FOV, R(2) = 94.6%; 9 inch FOV, R(2) = 94.8%; P<0.001; for depth: 6 inch FOV, R(2) = 99.3%; 9 inch FOV, R(2) = 99.3%; P<0.001) showing a strong linear relationship. For the diameter, the mean deviation from direct caliper measurements was 0.0625 mm and 0.08958 mm, respectively; for the 6 inch FOV and 9 inch FOV images, and for depth, the mean deviation was, respectively, -0.1001 mm and 0.09875 mm.

Cone beam CT yielded highly accurate and reproducible results in the quantitative assessment of periapical lesions.