Effect of Voxel Size on Detection of External Root Resorption Defects Using Cone Beam Computed Tomography

Abstract

BackgroundSelecting a voxel size that yields minimal radiation dose with no significant compromise of the diagnostic accuracy of cone beam computed tomography (CBCT) is particularly important.ObjectivesThis study aimed to assess the effect of voxel size on detection accuracy of simulated external root resorption defects using NewTom CBCT system.Materials and MethodsIn this diagnostic study, the roots of 90 extracted human central incisors were hypothetically divided into cervical, middle, and apical thirds. Variable-size defects were prepared in the buccal and lingual surfaces of the roots and CBCT scans were obtained with four different voxel sizes (150, 200, 250, and 300). Presence or absence of defects on CBCT scans was determined by three radiologists and the results were compared with the gold standard (actual size and depth of defects). Sensitivity and specificity values were calculated and reported for different groups.ResultsIn the lingual surfaces, the highest specificity and sensitivity belonged to 300µm voxel size (92.9%), and 200 and 250µm voxel sizes (both 97.4%) in the cervical third, respectively. In the middle third, the highest specificity and sensitivity belonged to 250 and 200µm voxel sizes (84.6% and 100%, respectively). In the apical third, the highest specificity and sensitivity belonged to 300 µm voxel size (100% and 97.9%, respectively). In the buccal surfaces, the highest specificity and sensitivity belonged to 150 (75.0%), 300 and 250 µm voxel sizes (100%) and the minimum values belonged to 200 µm voxel size (60% and 97.3%) in the cervical third. In the apical third, the highest specificity and sensitivity were noted in 300 µm voxel size (100% and 97.6%, respectively) and the minimum values were seen in 200 and 150 µm voxel sizes (93.8%, 90.5%, respectively). In the middle third, 300, 250 and 200 µm voxel sizes yielded the highest specificity (88.9%), while 150 µm voxel size yielded the highest sensitivity (98.8%).ConclusionConsidering the similar diagnostic efficacy of all voxel sizes, 300 µm voxel size can be used with adequate efficacy for detection of external root resorption defects with minimal patient radiation dose and the shortest scanning time.

Evaluating Diagnostic Efficacy of Cone Beam Computed Tomography Performed in Different Imaging Conditions Based on Field of View and Resolution in the Detection of Mandibular Condyle Erosions: An In Vitro Study

“…Their results showed similar diagnostic efficacies of all voxel sizes. Accordingly, they suggest that larger voxel size could be used with adequate efficacy for diagnosis of root resorption with minimal patient's dose and the shortest scanning time (16). The result of their study is in line with the current study in which we suggest using larger voxel size to reduce patient's dose.…”

The effect of varying cone beam computed tomography image resolution and field-of-view centralization on effective radiation dose

“…Several researches have attempted to identify indications for high resolution images 14. Some found no added benefit of these images when linear measurements are required or when resorption lesions are to be assessed 15,16. Other studies showed an advantage to high resolution imaging of root fractures that are not visualized on a periapical image 17,18.…”

“… 14 Some found no added benefit of these images when linear measurements are required or when resorption lesions are to be assessed. 15 , 16 Other studies showed an advantage to high resolution imaging of root fractures that are not visualized on a periapical image. 17 , 18 Other studies demonstrated varying results when these images are used for caries and root resorption detection.…”

Imaging diagnosis of external root resorption in replanted permanent teeth

“…experimental cavities made in the apical, middle and cervical thirds of human teeth to simulate external root resorption (ERR). 5,6,7,8,9,10,11,12 Moreover, ex vivo studies have evaluated CT sections, 13 voxel size, 14,15,16,17,18,19,20 and field of view (FOV) 14,19,21 for the best characterization of the resorption cavities in the CBCT images. The use of CBCT for diagnosing post-traumatic ERR was first described by Cohenca et al, 22 but only two clinical studies have investigated the performance of CBCT for the diagnosis of ERR in traumatized teeth.…”