[Diagnostic accuracy of cone beam computed tomography and eight-slice computed tomography for evaluation of external root reabsorption].
OBJECTIVE
To evaluate the diagnostic accuracy of cone beam computed tomography (CBCT) and high resolution multi-slice computed tomography  (MSCT) with eight-detector-rows in detecting the simulated external root resorption defects.


METHODS
External root resorption defects of different sizes  and in different locations were simulated in 40 human single rooted teeth. Cavities simulating root resorption defects of 1 mm in diameter and 0.1 mm, 0.2  mm, 0.3 mm, 0.4 mm in depth were drilled in the cervical, middle and apical thirds of lingual surfaces of the teeth. The specimens were scanned with both  CBCT (Accuitomo 3DX, Morita Co., Japan) and high resolution 8-slice CT (BrightSpeed Edge, GE Co., USA). The CBCT and MSCT images were read by  two experienced observers. The data were analyzed with receiver operating characteristics (ROC) analysis. ROC curves were generated and the area  under ROC curve (Az) was employed to express the diagnostic accuracy.


RESULTS
The diagnostic accuracy (Az value) in detecting the simulated  defects of all the locations and sizes were 0.921 for CBCT and 0.770 for MSCT. The Az values for CBCT in detecting defects located in the cervical, middle  and apical thirds were 0.885, 0.991 and 0.873, while those for MSCT were 0.752, 0.844 and 0.709, respectively. The Az values for CBCT in detecting the  defects of 0.1 mm, 0.2 mm, 0.3 mm and 0.4 mm in depth were 0.794, 0.934, 0.992 and 0.992, and those for MSCT were 0.592, 0.719, 0.920 and 0.990,  respectively.


CONCLUSIONS
The diagnostic ability for external root resorption of CBCT is better than that of MSCT. Smaller defects are better delineated  with CBCT than with MSCT. The defects in the middle thirds of the roots are easier to be detected than those in the cervical and apical ones using both  CBCT and MSCT.
Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
Xiao-yan
XY
Xie
Zu-yan
ZY
Zhang
D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D012391:Root Resorption / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*