Fig. 1.

Radiographic evaluation of periapical lesion. Radiographic images contain red-colored circles to indicate particular characteristics in the figures. (a): An OPG radiographic image of lower molar tooth number 36 shows substandard endo treatment with a large periapical lesion. b): An OPG radiographic image of an upper molar tooth reveals substandard root canal treatment with a large PA lesion in tooth number 16. The lower molar OPG radiograph reveals that tooth number 36 has good root canal treatment and normal apical tissue. (c): OPG radiographic image of upper molar shows tooth number 17 with substandard root canal treatment and a large PA lesion. (d): An OPG radiographic image of the lower molar tooth reveals that tooth # 37 has received good root canal treatment and had a large PA lesion.