Deborah Queiroz Freitas

Evaluation of Cone-beam Computed Tomography in the Diagnosis of Vertical Root Fractures: The Influence of Imaging Modes and Root Canal Materials

INTRODUCTION The purpose of this study was to evaluate the influence of cone-beam computed tomography (CBCT) imaging modes in the diagnosis of vertical root fractures with different intracanal materials. METHODS The sample consisted of 30 single-rooted teeth divided into 3 groups (n = 10), control and complete and incomplete root fracture. In each tooth, different materials were used (gutta-percha, metal post, and fiber post) as well as no filling material. Each tooth/root was scanned in a 3D Accuitomo 170 CBCT device by using 4 different imaging modes (high-resolution, high-fidelity, high-speed, and standard). In addition, the dose-area product was calculated for each CBCT imaging mode. The images were randomly evaluated by 5 dentomaxillofacial radiologists. RESULTS Complete root fractures were visualized more easily than incomplete fractures. The presence of metal post and gutta-percha negatively influenced the diagnosis of root fracture. Regarding the CBCT imaging modes, there was no influence for complete root fracture diagnosis. In cases of incomplete root fractures, high-fidelity, high-resolution, and standard had a higher diagnostic accuracy, especially in the fiber post and no filling groups. CONCLUSIONS The CBCT imaging modes had little influence in the diagnosis of complete and incomplete root fractures, whereas the presence of intracanal material had greater impact on the diagnostic ability, demonstrating that CBCT is not beneficial for the diagnosis of root fractures when metal posts are present.

Correlation of panoramic radiography and cone beam CT findings in the assessment of the relationship between impacted mandibular third molars and the mandibular canal

OBJECTIVES The aim of this study was to assess the reliability of four panoramic radiographic findings, both individually and in association, in predicting the absence of corticalization between the mandibular canal and the third molar on cone beam CT (CBCT) images. METHODS The sample consisted of 72 individuals (142 mandibular third molars) who underwent pre-operative radiographic evaluation before extraction of impacted mandibular third molars. On panoramic radiographs, the most common signs of corticalization (darkening of roots, diversion of mandibular canal, narrowing of mandibular canal and interruption of white line) and the presence or absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were evaluated. RESULTS Darkening of roots and interruption of white line associated with the absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were statistically significant, both as isolated findings (p = 0.0001 and p = 0.0006, respectively) and in association (p = 0.002). No statistically significant association was observed for the other panoramic radiographic findings, either individually or in association (p > 0.05). CONCLUSION Darkening of roots and interruption of white line observed on panoramic radiographs, both as isolated findings and in association, were effective in determining the risk relationship between the tooth roots and the mandibular canal, requiring three-dimensional evaluation of the case.

Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography

The aim of this study was to evaluate the validity of the bone density value of potential implant sites in HU obtained by a specific cone-beam computed tomography (CBCT) device. In this study, the HU values obtained using a MSCT scanner were used as the gold standard. Twenty mandibles (40 potential implant sites) were scanned using an MSCT scanner (Somatom Sensation 40) and a CBCT scanner (i-CAT). The MSCT images were evaluated using the Syngo CT Workplace software and the CBCT images, using the XoranCat software. The images were evaluated twice by three oral radiologists, at 60 day intervals. The trabecular bone density of the same area was evaluated on both images. Intraclass coefficients (ICC) were calculated to examine the agreement between the examiners and between the two periods of evaluation. The bone density and area of the ROI were compared by the Student t test and Bland-Altman analysis. ICCs were excellent. The mean HU value obtained using CBCT (418.06) was higher than that obtained using MSCT (313.13), with a statistically significant difference (p < 0.0001). In addition, Bland-Altman analysis showed that the HU measures were not equivalent. In conclusion, the bone density in HU with CBCT images obtained using the device studied proved unreliable, since it was higher than that obtained using MSCT.

Diagnostic reproducibility of the elongated styloid process

UNLABELLED The aim of this study was to estimate the reproducibility related to the presence and to the measurements of elongated styloid process (ESP), based on panoramic radiographs and the prevalence of ESP. EXPERIMENTAL DESIGN one hundred sixty six panoramic radiographs were used, from edentulous patients from the Radiology Clinic files, at Araraquara Dental School, Unesp, during a four-year period. One hundred and twenty one were female and 45 were male. Two calibrated observers evaluated the radiographs. A caliper was used to measure, in mm, the ESP from the base of the temporal bone to the tip of the structure. The ESP was considered present when the measurements were 30mm or more. Kappa statistics (k ) and intra-class correlation coefficient (r ), were applied to estimate the reproducibility. The results showed that related to the presence of ESP, the interobserver agreement was k =0.85. Related to the measurements of ESP, the interobserver agreement was r =0.52. The prevalence of ESP was estimated in 12.6%. ESP distribution in females was similar to that for males. In conclusion, we found a greater level of agreement when observers evaluated the presence of ESP than when they did the measurement of ESP. The prevalence of ESP was 12.6%.

Influence of the artefact reduction algorithm of Picasso Trio CBCT system on the diagnosis of vertical root fractures in teeth with metal posts

OBJECTIVES To assess the influence of the artefact reduction algorithm (AR) available on the Picasso Trio 3D(®) imaging system (Vatech, Hwaseong, Republic of Korea) on image quality [greyscale values, contrast-to-noise ratio (CNR) and artefact formation] and diagnosis of vertical root fractures (VRFs) in the teeth with intracanal metal posts. METHODS 30 uniradicular teeth had their crowns removed and their roots endodontically treated to receive intracanal metal posts. In 20 teeth, both complete (n = 10) and incomplete (n = 10) VRFs were created. Each tooth was scanned twice, with and without AR activation. The mean and variation of greyscale values, as well as CNR, were calculated for all images. Subsequently, an evaluator compared the amount of artefact (cupping, white streaks and dark bands) in all images. Five evaluators rated for VRF presence using a five-point scale. RESULTS Mean greyscale values and CNR were significantly decreased in images acquired with the AR. The usage of the algorithm promoted an overall reduction of image artefacts. Regarding the diagnosis of complete and incomplete VRFs, the use of the AR had an overall negative impact on specificity and accuracy. CONCLUSIONS While indeed reducing artefact formation, the use of the AR, instead of improving the impact on the diagnosis of VRFs in teeth with intracanal metal posts, had a negative impact on the diagnosis.

Evaluation of reconstructed images with different voxel sizes of acquisition in the diagnosis of simulated external root resorption using cone beam computed tomography

AIM   To evaluate the diagnosis of simulated external root resorption in cone beam computed tomography (CBCT) images acquired with different voxel sizes, then reconstructed with the same voxel size. METHODOLOGY   Buccal, mesial and distal root surfaces of twenty single-rooted premolar teeth were evaluated for the presence or absence of simulated resorption defects. Images were obtained using a Classic i-CAT CBCT unit with two different voxel sizes (0.25 and 0.30 mm). Then all images were reconstructed to 0.25 mm voxel size. The McNemars test was applied to evaluate the agreement between the two protocols (different voxel sizes/reconstruction parameters) with the gold standard (defects created in the root). Accuracy, sensitivity, specificity, positive and negative predictive values were calculated for each voxel and defect sizes. RESULTS   Better sensitivity and accuracy were obtained with 0.25 (0.25 mm) voxel size. Specificity, positive and negative predictive values were highest with the 0.25 (0.30 mm) voxel size. McNemars test results revealed significant differences between the protocols with the gold standard (P < 0.0001). The results revealed that as the cavity size increased, sensitivity, accuracy, positive and negative predictive values also increased. When correlating the voxel size and root third, better sensitivity, accuracy, positive and negative predictive values were obtained in the middle third. CONCLUSIONS   In the diagnosis of simulated external root resorption with the Classic i-CAT CBCT unit, images acquired with 0.30 mm voxel size and reconstructed with 0.25 mm voxel size provided the best protocol with a lower radiation dose than the 0.25 mm voxel size.

Influence of exposure factors on the variability of CBCT voxel values: a phantom study

OBJECTIVES To assess the influence of milliamperage and kilovolt peak (kVp) on the variability of cone beam CT (CBCT) voxel values. METHODS CBCT scans were obtained from radiographic phantoms in varying concentrations of dipotassium hydrogen phosphate solutions (200-1200 mg ml(-1)) under different protocols of milliamperage and kVp. In addition, scans were performed with and without a dental implant and exo-mass. The variability of CBCT voxel values was measured on each scan, and factorial analysis of variance and the post hoc Tukey test were performed (α = 0.05). Linear regression was performed to assess the relationship between voxel value variability and dipotassium hydrogen phosphate concentration. RESULTS milliamperage and the presence of a dental implant did not produce significant interference (p = 0.28 and 0.87, respectively) in voxel value variability. Scans at the highest kVp value presented a significant reduction (p ≤ 0.0001) in voxel value variability when only exo-mass was not present. Voxel value variability was not influenced by exo-mass in scans at the highest levels of milliamperage and kVp. The presence of exo-mass produced a significant reduction (p ≤ 0.0001) in voxel value variability in most of the scans. Higher concentrations yielded greater variations in voxel values in all scans, except for those operating at the highest levels of mAs and kVp. CONCLUSIONS mAs did not influence the variability of CBCT voxel values; higher kVp reduced such variability when only the object was smaller than the field of view.

Influence of Cone-Beam Computed Tomography Enhancement Filters on Diagnosis of Simulated External Root Resorption

INTRODUCTION The aim of this study was to determine if cone-beam computed tomography (CBCT) enhancement filters influence the diagnosis of simulated external root resorption (ERR). METHODS Buccal, mesial, and distal root surfaces of 20 single-rooted premolar teeth were evaluated for the presence or absence of simulated defects. Images were obtained using a Classic i-CAT CBCT device (Imaging Sciences International, Inc, Hatfield, PA) and analyzed by 3 oral radiologists. Evaluations were performed with and without CBCT filters. Accuracy, sensitivity, specificity, and positive and negative predictive values were determined. The McNemar test verified the disagreement between all images versus the gold standard and original images versus images with filters; P values < .05 were considered statistically significant. Inter- and intraobserver agreement was calculated by the kappa test. RESULTS The means of intra- and interobserver agreement ranged from good to excellent. Sharpen 3×3 had the highest sensitivity (0.64), accuracy (0.62), and negative predictive value (0.33). Specificity was the highest (0.56) for S9, Smooth, Smooth 3×3, and Angio Sharpen High filters. Positive predictive values were the highest (0.81) for the Smooth 3×3 and Angio Sharpen High filters. The McNemar test showed statistically significant differences from the gold standard for all images (P < .05) as well as for original images versus images with the Shadow filter (P = .01). The other filters did not show statistically significant differences from the original images. CONCLUSIONS The influence of enhancement CBCT filters on ERR diagnosis is small. The Sharpen 3×3 filter gave the best results and the Shadow filter the worst results.

Influence of CBCT enhancement filters on diagnosis of vertical root fractures: a simulation study in endodontically treated teeth with and without intracanal posts.

OBJECTIVES To evaluate the influence of CBCT enhancement filters on the diagnosis of vertical root fractures (VRFs) in teeth with and without metal posts. METHODS The crowns of 40 uniradicular human teeth were removed and all roots were prepared. 20 teeth were randomly selected, and VRFs were induced using a universal testing machine. The i-CAT (Imaging Sciences International, Hatfield, PA) CBCT was used to scan teeth with and without intracanal metal posts using the following parameters: 0.2 voxel size, 8 × 8-cm scan size and acquisition time of 26.9 s. Images were evaluated by three observers with and without the use of the following filters: S9, smooth, smooth 3 × 3, sharpen, sharpen-mild and sharpen 3 × 3. RESULTS Intra- and interobserver agreement ranged from poor to moderate. Images with and without CBCT filters did not show significant differences regarding the area under the receiver operating characteristic curve, as well as sensitivity (p > 0.05). As for accuracy, the sharpen-mild filter was superior to the sharpen (p = 0.03), but these filters did not differ from all others. For specificity, S9, smooth and original images were superior to sharpen (p < 0.01). Results for teeth without posts differed from those for teeth with metal posts in all cases (p < 0.05). CONCLUSIONS The use of enhancement filters in CBCT images has no influence on the diagnosis of VRFs in teeth with metal posts, and their use is not justified.

Prevalence and characteristics of pneumatization of the temporal bone evaluated by cone beam computed tomography.

The aim of this study was to determine the prevalence and characteristics of pneumatization of the glenoid fossa and articular eminence by means of cone beam computed tomography (CBCT) images. CBCT images of 658 patients (1316 joints) were evaluated to determine pneumatization in the articular eminence (PAT) and roof of the glenoid fossa (PGF). Age and gender were recorded for all patients and, for the cases of pneumatization, laterality and type (unilocular or multilocular) were noted. Its prevalence was correlated with gender, age and laterality by statistical analyses. 21.3% of individuals presented with PAT and 38.3% presented with PGF. Considering the temporomandibular joint, PAT was in 15.5% and PGF in 30.2%. Of PAT cases, 54.3% were unilateral and 45.7% bilateral; 3.4% were unilocular and 96.6% were multilocular. In the PGF cases, 42.5% were unilateral and 57.5% bilateral; 0.02% was unilocular and 99.8% were multilocular. There was no statistical difference regarding gender and age; but there was statistical difference regarding laterality, with higher frequency on the left side. In conclusion, there was a significant prevalence of PAT and PGF in the studied population; their prevalence seems higher than has been previously supposed.