Area and 3-dimensional volumetric changes of periapical lesions after root canal treatments.

Introduction: This study compared the changes in size of periapical lesions after root canal treatment as revealed by periapical radiography (PA) and cone-beam computed tomography (CBCT) imaging using area and 3-dimensional volumetric measurements and assessed the outcome of the treatments based on these parameters.

Methods: Both PA and CBCT scans were taken preoperatively and at recall. In total, 50 teeth (71 roots) with evidence of periapical bone loss on both PA and CBCT images were endodontically treated and followed for 10-37 months. The area and volume of periapical lesions were measured, and changes were presented in the following 4 categories: lesion undetected, lesion reduced in size, lesion unchanged, or lesion enlarged. The McNemar and chi-square tests were used to compare the lesion changes determined by CBCT imaging and PA.

Results: The 4-category diagnosis made using both methods were in agreement in 39 of 71 (54.9%) roots, whereas disagreement was observed in 32 of 71 (45.1%) roots (P < .001). At recall, lesion was absent in 11 of 71 (15.5%) roots on CBCT scans and 32 of 71 (45.1%) roots on PA (P < .001). When success was defined as the absence of a lesion or a reduction in size of a lesion, 55 (77.5%) roots on CBCT imaging showed success and 63 (88.7%) roots on PA (P = .073).

Conclusions: Changes in lesion size after root canal treatment determined with 3-dimensional volumetric CBCT data and 2-dimensional PA data are different. The outcome of root canal treatments determined with PA could be untrue.