PURPOSE: To determine whether calcified carotid atherosclerotic plaques (CCAPs) and mineralized laryngeal cartilages (MLCs) were more frequently detected on digital or film-based panoramic radiographs. The clinical relevance of this question is that some radiopacities seen on digital radiographs may correspond to medium-density tissues that are not necessarily mineralized. MATERIALS AND METHODS: Data were collected from panoramic radiographs and the respective reports issued by 2 private oral radiology centers. A total of 388 radiographs and reports were divided into film-based (group A) and digital (group D) radiographs. The frequencies of CCAPs and MLCs were analyzed using the Fisher exact test, and odds ratios were also calculated (α=1%). RESULTS: The mean age of patients whose reports and radiographs showed CCAPs and/or MLCs ranged from 50.1 to 54.1 years. There was a predominance of females. A higher frequency of CCAPs and MLCs was observed in group D than in group A at both centers (P<0.01). CCAPs and MLCs were detected 4 times more frequently in group D than in group A at one of the centers. CONCLUSION: CCAPs and MLCs were more frequently detected on digital than on film-based panoramic radiographs. Further studies are needed to determine whether such radiopacities do indeed correspond to mineralized, rather than medium-density, tissues.
Atherosclerosis ; Female ; Humans ; Incidental Findings ; Laryngeal Cartilages ; Miners ; Odds Ratio ; Plaque, Atherosclerotic ; Radiography, Dental, Digital ; Radiography, Panoramic

Purpose: The aim of this study was to objectively detect simulated tooth ankylosis using a novel method involving cone-beam computed tomography (CBCT). Materials and Methods: Tooth ankylosis was simulated in single-rooted human permanent teeth, and CBCT scans were acquired at different current levels (5, 6.3, and 8 mA) and voxel sizes (0.08, 0.125, and 0.2). In axial reconstructions, a line of interest was perpendicularly placed over the periodontal ligament space of 21 ankylosed and 21 non-ankylosed regions, and the CBCT grey values of all voxels along the line of interest were plotted against their corresponding X-coordinates through a line graph to generate a profile. The image contrast was increased by 30% and 60% and the profile assessment was repeated. The internal area of the resulting parabolas was obtained from all images and compared between ankylosed and non-ankylosed regions under different contrast enhancement conditions, voxel sizes, and mA levels using multi-way analysis of variance with the Tukey post hoc test (α=0.05). Results: The internal area of the parabolas of all non-ankylosed regions was significantly higher than that of the ankylosed regions (P<0.05). Contrast enhancement led to a significantly greater internal area of the parabolas of non-ankylosed regions (P<0.05). Overall, voxel size and mA did not significantly influence the internal area of the parabolas (P>0.05). Conclusion The proposed novel method revealed a relevant degree of applicability in the detection of simulated tooth ankylosis; increased image contrast led to greater detectability.

Purpose: This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode. Materials and Methods: CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium.These cylinders were placed within the overlapping zones of the stitching reconstruction area. For each material, 3 acquisitions were conducted: 1 utilizing the automatic stitching process with a FOV of 80 × 37 mm, and 2 with smaller FOVs of 50 × 37 mm. For the smaller FOVs, 1 scan targeted the anterior region, while the other focused on the left posterior region. Thus, 3 groups were formed: stitched FOV, anterior FOV, and posterior FOV. Artifact expression was assessed by calculating the means and standard deviations (SDs) of the gray values in 4 regions of interest located anteriorly, posteriorly, medially, and laterally to the cylinders. Analysis of variance was used to compare the data, with an alpha level of 5%. Results: The stitched FOV exhibited lower SD values than the posterior and anterior FOVs (P<0.05). Regarding the materials evaluated, amalgam, cobalt-chromium, and zirconium generally demonstrated higher SDs of the gray values than gutta-percha and titanium (P<0.05). Conclusion Horizontally stitched CBCT images demonstrated lower artifact expression compared to the traditional mode of acquisition.

Purpose: This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode. Materials and Methods: CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium.These cylinders were placed within the overlapping zones of the stitching reconstruction area. For each material, 3 acquisitions were conducted: 1 utilizing the automatic stitching process with a FOV of 80 × 37 mm, and 2 with smaller FOVs of 50 × 37 mm. For the smaller FOVs, 1 scan targeted the anterior region, while the other focused on the left posterior region. Thus, 3 groups were formed: stitched FOV, anterior FOV, and posterior FOV. Artifact expression was assessed by calculating the means and standard deviations (SDs) of the gray values in 4 regions of interest located anteriorly, posteriorly, medially, and laterally to the cylinders. Analysis of variance was used to compare the data, with an alpha level of 5%. Results: The stitched FOV exhibited lower SD values than the posterior and anterior FOVs (P<0.05). Regarding the materials evaluated, amalgam, cobalt-chromium, and zirconium generally demonstrated higher SDs of the gray values than gutta-percha and titanium (P<0.05). Conclusion Horizontally stitched CBCT images demonstrated lower artifact expression compared to the traditional mode of acquisition.

Purpose: This study was performed to evaluate the expression of beam hardening artifacts generated by high atomic number materials in stitched cone-beam computed tomography (CBCT) images, compared to the traditional acquisition mode. Materials and Methods: CBCT volumes were acquired using an acrylic resin phantom embedded with pairs of cylinders made from amalgam dental alloy, cobalt-chromium alloy, gutta-percha, titanium, and zirconium.These cylinders were placed within the overlapping zones of the stitching reconstruction area. For each material, 3 acquisitions were conducted: 1 utilizing the automatic stitching process with a FOV of 80 × 37 mm, and 2 with smaller FOVs of 50 × 37 mm. For the smaller FOVs, 1 scan targeted the anterior region, while the other focused on the left posterior region. Thus, 3 groups were formed: stitched FOV, anterior FOV, and posterior FOV. Artifact expression was assessed by calculating the means and standard deviations (SDs) of the gray values in 4 regions of interest located anteriorly, posteriorly, medially, and laterally to the cylinders. Analysis of variance was used to compare the data, with an alpha level of 5%. Results: The stitched FOV exhibited lower SD values than the posterior and anterior FOVs (P<0.05). Regarding the materials evaluated, amalgam, cobalt-chromium, and zirconium generally demonstrated higher SDs of the gray values than gutta-percha and titanium (P<0.05). Conclusion Horizontally stitched CBCT images demonstrated lower artifact expression compared to the traditional mode of acquisition.

Purpose: This study examined the influence of a metal artifact reduction (MAR) tool, sharpening filters, and their combination on the diagnosis of vertical root fracture (VRF) in teeth with metallic posts using cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human premolars - 9 with VRF and 11 without - were individually placed in a human mandible. A metallic post composed of a cobalt-chromium alloy was inserted into the root canal of each tooth. CBCT scans were then acquired under the following parameters: 8 mA, a 5 × 5 cm field of view, a voxel size of 0.085 mm, 90 kVp, and with MAR either enabled or disabled. Five oral and maxillofacial radiologistsindependently evaluated the CBCT exams under each MAR mode and across 3 sharpening filter conditions: no filter, Sharpen 1 × , and Sharpen 2 × . The diagnostic performance was quantified by the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. These metrics were compared using 2-way analysis of variance with a significance level of α = 5%. Intra- and inter-examiner agreement were assessed using the weighted kappa test. Results: Neither MAR nor the application of sharpening filters significantly impacted AUC or specificity (P>0.05). However, sensitivity increased when MAR was combined with Sharpen 1 × and Sharpen 2 × (P = 0.015). The intraexaminer agreement ranged from fair to substantial (0.34-0.66), while the inter-examiner agreement ranged from fair to moderate (0.27-0.41). Conclusion MAR in conjunction with sharpening filters improved VRF detection; therefore, their combined use is recommended in cases of suspected VRF.

PURPOSE: To evaluate the effect of different numbers of basis images and the use of metal artifact reduction (MAR) on the production and reduction of artifacts in cone-beam computed tomography images. MATERIALS AND METHODS: An acrylic resin phantom with a metal alloy sample was scanned, with 450 or 720 basis images and with or without MAR. Standard deviation values for the test areas (around the metal object) were obtained as a way of measuring artifact production. Two-way analysis of variance was used with a 5% significance level. RESULTS: There was no significant difference in artifact production among the images obtained with different numbers of basis images without MAR (P=.985). MAR significantly reduced artifact production in the test areas only in the protocol using 720 basis images (P=.017). The protocol using 450 basis images with MAR showed no significant difference in artifact production when compared to the protocol using 720 basis images with MAR (P=.579). CONCLUSION: Protocols with a smaller number of basis images and with MAR activated are preferable for minimizing artifact production in tomographic images without exposing the patient to a greater radiation dose.
Alloys ; Artifacts ; Cone-Beam Computed Tomography ; Humans ; Phantoms, Imaging

Purpose: The purpose of this study was to evaluate the image quality, diagnostic efficacy, and radiation dose associated with the use of a cadmium telluride (CdTe) detector, compared to charge-coupled device (CCD) and complementary metal oxide semiconductor (CMOS) detectors. Materials and Methods: Lateral cephalographs of a phantom (type 1) composed of synthetic polymer filled with water and another phantom (type 2) composed of human skull macerated with polymer coating were obtained with CdTe, CCD, and CMOS detectors. Dosimeters placed on the type 2 phantom were used to measure radiation. Noise levels from each image were also measured. McNamara cephalometric analysis was conducted, the dentoskeletal configurations were assessed, and a subjective evaluation of image quality was conducted. Parametric data were compared via 1-way analysis of variance with the Tukey post-hoc test, with a significance level of 5%. Subjective image quality and dentoskeletal configuration were described qualitatively. Results: A statistically significant difference was found among the images obtained with the 3 detectors (P<0.05), with the lowest noise level observed among the images obtained with the CdTe detector and a higher subjective preference demonstrated for those images. For the cephalometric analyses, no significant difference (P>0.05) was observed, and perfect agreement was seen with regard to the classifications obtained from the images acquired using the 3 detectors. The radiation dose associated with the CMOS detector was higher than the doses associated with the CCD (P<0.05) and CdTe detectors (P<0.05). Conclusion Considering the evaluated parameters, the CdTe detector is recommended for use in clinical practice.

Objectives: The aim of this study was to evaluate the influence of peak kilovoltage (kVp) and a metal artifact reduction (MAR) tool on image quality and the diagnosis of vertical root fracture (VRF) in cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human teeth filled with an intracanal metal post were divided into 2 groups: control (n = 10) and VRF (n = 10). Each tooth was placed into the socket of a dry mandible, and CBCT scans were acquired using a Picasso Trio varying the kVp (70, 80, 90, or 99), and the use of MAR (with or without). The examinations were assessed by 5 examiners for the diagnosis of VRF using a 5-point scale. A subjective evaluation of the expression of artifacts was done by comparing random axial images of the studied protocols. The results of the diagnoses were analyzed using 2-way analysis of variance and the Tukey post hoc test, the subjective evaluations were compared using the Friedman test, and intra-examiner reproducibility was evaluated using the weighted kappa test (α = 5%). Results: The kVp and MAR did not influence the diagnosis of VRF (p > 0.05). According to the subjective classification, the 99 kVp protocol with MAR demonstrated the least expression of artifacts, while the 70 kVp protocol without MAR led to the most artifacts. Conclusions Protocols with higher kVp combined with MAR improved the image quality of CBCT examinations. However, those factors did not lead to an improvement in the diagnosis of VRF.