This study assesses whether variations to cone-beam computed tomography (CBCT) slice thickness (ST) effect the detection accuracy and volume assessment of periapical lesions.

Forty periapical lesions were assessed on CBCT reconstructions with 0.125-mm, 0.25-mm, 0.50-mm, 1.00-mm, 1.50-mm, and 2.00-mm ST. Mimics Research was used to perform the semi-automatic segmentation technique to determine periapical lesion volume and CBCT periapical volume index (CBCTPAVI) score on each CBCT reconstruction. Diagnostic accuracy was assessed by determining the percentage of lesions detected on each reconstruction, and the Friedman test was conducted to assess for significant differences in lesion volume between the different CBCT reconstructions. Differences among CBCTPAVI scores were also assessed.

Periapical lesion volume was significantly underestimated on CBCT reconstructions with ST above 1.00 mm. Variations in periapical lesion volume were the greatest among smaller lesions resulting in false negative diagnoses with the utilization of CBCTs with ST above 0.50 mm.

Variations in CBCT ST can significantly influence measured periapical lesion volume, and failure to account for this may lead to misinterpretation of lesion progression or healing. A minimum ST of 0.50 mm was required for the reliable detection of all periapical lesions, and this threshold serves as a benchmark for optimizing CBCT acquisition protocols to preserve diagnostic accuracy while minimizing radiation exposure.