The aim of the study was compare the sensitivity and measurements obtained from teeth with apical lesions scheduled for periapical surgery using three different diagnostic methods: periapical radiography (Gendex Expert DC), panoramic radiography (Planmeca® Promax 3D Classic) and cone beam computed tomography (CBCT) (Planmeca® Promax 3D Classic). This cross-sectional study involved 35 patients (45 teeth) scheduled for periapical surgery in which periapical radiographs, panoramic radiographs and CBCT scans had been obtained. The images were used to analyze the maximum vertical and horizontal dimension and the resulting areas of the periapical lesions based on the three diagnostic methods. The two-dimensional techniques (periapical radiography and panoramic radiography) yielded a sensitivity of 82% versus 100% in the case of CBCT. The mean vertical dimension of the apical areas was 5.48 mm with periapical radiography and 5.04 mm with panoramic radiography ? the difference with respect to CBCT being statistically significant (6.36 mm for the coronal sections). There were no significant differences among the three techniques in terms of horizontal dimension (p>0.05) or lesion area. The sensitivity of periapical radiolucencies detected using CBCT was significantly greater than with the two-dimensional imaging techniques. Significant differences between the latter and CBCT were only observed in the case of the vertical measurements.