Influence of exposure parameters on the detection of simulated root fractures in the presence of various intracanal materials.

AIM: To investigate how the exposure parameters used when producing CBCT scans affect diagnostic accuracy when detecting simulated vertical root fractures and how various filling materials affect image quality. METHODOLOGY: A total of 160 extracted single-rooted human teeth were divided into four groups based on the materials within the root canals: unrestored, gutta-percha, metallic post and fibreglass post. Half of the sample of each group was selected for the induction of vertical root fractures. Each tooth was placed in an empty socket of a dry skull which was scanned on a CBCT unit (9000 3D scanner; Kodak Dental Systems, Carestream Health, Rochester, NY, USA) using the following exposure parameters: 74 kV/12 mA; 74 kV/10 mA; 74 kV/8 mA; 74 kV/6.3 mA; 70 kV/12 mA; 70 kV/10 mA; 70 kV/8 mA; 70 kV/6.3 mA. Two observers assessed all images using a 5-point confidence scale for fracture detection and a 4-point score for the presence of artefacts. Sensitivity, specificity, accuracy and area under ROC curve were compared by two-way anova and Tukey's test. Artefact formation was evaluated by descriptive statistics. RESULTS: There were no significant differences in the sensitivity (P = 0.370), specificity (P = 0.660), accuracy (P = 0.084) and area under the ROC curve (P = 0.674) values amongst the various exposure parameters within the same group. There were some significant differences when the groups were compared for each intracanal material. The sensitivity and accuracy of the group containing metallic posts were significantly lower than the unrestored and fibreglass post groups (P ≤ 0.017). CONCLUSION: The variations in exposure parameters did not interfere with the diagnosis of vertical root fractures, independent of the root canal restorative status. Metallic posts were associated with greater artefact formation and compromised the diagnostic performance. It is possible to decrease the kVp/mA settings to reduce the probability of biological effects due to radiation, without losing diagnostic accuracy.

Performance of an artefact reduction algorithm in the diagnosis of in vitro vertical root fracture in four different root filling conditions on CBCT images.

AIM: To evaluate the influence of an artefact reduction algorithm (ARA) and several root filling materials on the detection of root fractures on cone-beam computed tomography (CBCT) images. METHODOLOGY: Forty-four teeth were divided into control and fractured groups and scanned on a Picasso Trio CBCT device under four conditions: unrestored, filled with gutta-percha cones, cast-gold or fibreglass posts; either with or without applying the ARA. Three calibrated examiners assessed the images. ROC analysis, anova and pairwise Tukey LSD test were performed. RESULTS: No significant difference between the groups with and without the ARA was observed. There was no significant interaction between the algorithm and root condition. On the other hand, there was a significant difference in the mean values of sensitivity (Sn) and accuracy (Ac) amongst the different root filling groups (P ≤ 0.001). CONCLUSIONS: The application of the ARA did not influence the diagnosis of root fractures, and its effects did not depend on root conditions. In relation to the filling materials, gold posts reduced the overall CBCT diagnostic ability, regardless of the use of the ARA.