Effect of delayed scanning on imaging and on the diagnostic accuracy of vertical root fractures in two photostimulable phosphor plates digital systems.

AIM: To evaluate the influence of delayed scanning on images obtained with two PSPs digital systems and on the diagnostic accuracy of vertical root fracture (VRF) by means of objective and subjective analyses. METHODOLOGY: Forty single-rooted human teeth were divided into two groups, one without VRFs and another with VRFs induced by a universal testing machine. Two digital systems (VistaScan(®) and Express(®) ) were used to radiograph all teeth, and the resulting plates were scanned at four time-points: T0-immediately, T1-30 min, T2-2 h and T3-4 h after exposure. An aluminium (Al) wedge was used to evaluate the change in mean grey values as each scan was delayed. Three observers screened all images for VRFs, and one-fourth of the sample was revaluated after thirty days. Areas under the receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy values were compared by anova. RESULTS: Intra- and interobserver agreement ranged from moderate to substantial and fair to moderate, respectively. There was no significant difference amongst scan delays with regard to sensitivity, specificity and accuracy; however, there were significant differences in the area under the ROC curve, with the 4-h delayed scan being associated with lower values compared to the others (P = 0.019). As for objective analysis, there was a significant difference amongst all different scanning time-points for the two systems (P = 0.001), except between the 30-min and 2-h delayed scans in the VistaScan(®) system. CONCLUSION: Whilst delayed scanning caused changes to the density of images acquired with the systems studied, it did not seem to interfere with VRF diagnosis except when scanning was delayed for 4 h, which should therefore be avoided.

Digital radiographs displayed on different devices: effect on the detection of vertical root fractures.

AIM: To evaluate whether the type of display device affects the detection of vertical root fractures (VRFs) on digital radiographs in unfilled canals and canals with fibreglass posts. METHODOLOGY: Forty single-rooted human teeth were decoronated, and the root canals were prepared. The teeth were divided into 2 groups: controls (20 teeth) and with VRF (20 teeth). The VRFs were induced using an universal testing machine. Periapical radiographs of all teeth, with canal unfilled or with a fibreglass post, were obtained using the parallel technique in 3 directions (ortho-, mesio- and distoradial) on storage phosphor plates (VistaScan®). All images were evaluated and re-evaluated after 30 days by 3 examiners on a 5-point scale using 4 different devices (notebook display with full high definition resolution, desktop display with a standard resolution, 8-inch Android(™) tablet with high definition resolution and a 9.7-inch iPad® tablet with Retina resolution). Areas under ROC curves, sensitivity, specificity and accuracy values were compared by anova. RESULTS: The weighted kappa values for intra- and interobserver reproducibility were 0.55-0.88 and 0.31-0.65, respectively. There was a significant difference (P < 0.05) in relation to the area under the ROC curve, specificity and sensitivity when unfilled canals were compared with canals with a fibreglass post; however, no difference was observed for the different devices studied. CONCLUSIONS: The type of display device did not affect the detection of VRFs. Thus, the detection of VRFs can be performed using different screen sizes and resolutions.

Impact of root fillings and posts on the diagnostic ability of three intra-oral digital radiographic systems in detecting vertical root fractures.

AIM: To evaluate (i) the accuracy of three intra-oral digital systems in detecting vertical root fractures (VRFs); and (ii) the influence of different intracanal conditions (without filling, filled with Gutta-percha and metal or fibreglass post). METHODOLOGY: Forty single-rooted human teeth were decoronated and the root canals prepared. VRFs were induced using a universal testing machine on 20 teeth. Radiographic images were obtained using the paralleling technique with three different horizontal angulations on conventional E/F film, two storage phosphor plates (Digora Optime and VistaScan) and one sensor system (SnapShot). All teeth were radiographed with all intracanal conditions tested. All images were evaluated by five examiners. After 30 days, 25% of the images were reviewed. Areas under ROC curves, sensitivity, specificity, accuracy, positive predictive and negative predictive values were compared by anova. RESULTS: The weighted kappa values for intra- and interobserver reproducibility were 0.48-0.74 and 0.57-0.66, respectively. The sensitivity revealed a significant difference between imaging modalities, with higher values for SnapShot (0.53) and VistaScan (0.46), followed by the film (0.41) and Digora (0.38). The area under the ROC curve for SnapShot (0.82) was greater than for the other systems in the teeth with a fibreglass post (VistaScan: 0.70; Digora: 0.64; film: 0.60). CONCLUSION: All systems gave a similar performance for detecting VRFs; all gave a good performance in the absence of intracanal materials, but performed less well in the presence of a metal post or Gutta-percha. In teeth with a fibreglass post, digital systems with higher resolution should be used.

The 'Sharpen' filter improves the radiographic detection of vertical root fractures.

AIM: To compare the diagnostic accuracy of digital enhancement filters in the diagnosis of vertical root fractures. METHODOLOGY: The sample consisted of 40 single-rooted teeth randomly divided into two groups: experimental and control. Vertical root fractures were induced in the experimental group using a universal testing machine. All teeth were individually radiographed with three different horizontal angles using the Digora Optime(®) digital system. Three observers separately examined the original and filtered images (3D Emboss, Negative, Sharpen and Shadow). The area under Receiver Operating Characteristic curve values (Az) for each protocol were compared by one-way anova with post hoc Bonferroni test. The significance level was set at 5%. RESULTS: The highest Az value was obtained using the Sharpen filter, with significant differences from the original and other filtered images (P < 0.05). The 3D Emboss filter had the lowest Az value, which was significantly different from the other filtered images (P < 0.05). CONCLUSION: When using the Digora Optime(®) system, the 'Sharpen' filter is recommended to improve the radiographic detection of vertical root fractures.