Figure 1.

Post-processing of CBCT imaging in Case 1: (a) digital periapical radiography showing the radiolucent image associated with the roots of tooth no. 16 (arrow). (b) A CBCT sagittal slice (T0) demonstrating the periradicular lesion next to the maxillary sinus before the endodontic re-treatment (arrow). (c) A CBCT sagittal slice (T1) demonstrating the periradicular lesion 6 months after the re-treatment (arrow). (d–g) Segmentation, using threshold tool, and construction of virtual three-dimensional (3D) model before the endodontic re-treatment (red label) and 6 months later (yellow label). (h) Virtual 3D models aligned and overlapped. (i, j) Palatal and buccal views of virtual 3D model of periradicular lesion before the re-treatment (translucent) and after re-treatment (colourful). (k) Qualitative and quantitative assessment by colour maps and “point value” tool revealed a greater reduction in the palatal portion of the lesion (3.4 mm).