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: This study was performed to evaluate the magnitude of artifacts produced by gutta-percha and metal posts on cone-beam computed tomography (CBCT) scans obtained with different tube currents and with or without metal artifact reduction (MAR). MATERIALS AND METHODS: A tooth was inserted in a dry human mandible socket, and CBCT scans were acquired after root canal instrumentation, root canal filling, and metal post placement with various tube currents with and without MAR activation. The artifact magnitude was assessed by the standard deviation (SD) of gray values and the contrast-to-noise ratio (CNR) at the various distances from the tooth. Data were compared using multi-way analysis of variance. RESULTS: At all distances, a current of 4 mA was associated with a higher SD and a lower CNR than 8 mA or 10 mA (P<0.05). For the metal posts without MAR, the artifact magnitude as assessed by SD was greatest at 1.5 cm or less (P<0.05). When MAR was applied, SD values for distances 1.5 cm or closer to the tooth were reduced (P<0.05). MAR usage did not influence the magnitude of artifacts in the control and gutta-percha groups (P>0.05). CONCLUSION Increasing the tube current from 4 mA to 8 mA may reduce the magnitude of artifacts from metal posts. The magnitude of artifacts arising from metal posts was significantly higher at distances of 1.5 cm or less than at greater distances. MAR usage improved image quality near the metal post, but had no significant influence farther than 1.5 cm from the tooth.

Purpose: This study was conducted to compare the objective image quality of radiographs acquired with a handheld X-ray device to those obtained with a wall-mounted X-ray device. Materials and Methods: Brightness, noise, uniformity, and contrast were evaluated. To assess the first 3 parameters,radiographs of an acrylic block were acquired with an unused photostimulable phosphor (PSP) plate from the VistaScan system (Mini Easy, Dürr Dental, Bietigheim-Bissingen, Germany). Initially, 6 radiographs were taken with a Focus X-ray wall-mounted device (Instrumentarium, Tuusula, Finland) operating at 60 kVp, 7 mA, and 0.125 s.Another 6 radiographs were captured using an Eagle handheld X-ray device (Alliage, São Paulo, Brazil) at 60 kVp, 2.5 mA, and 0.35 s. The means and standard deviations of the gray values for all radiographs were calculated using ImageJ (National Institutes of Health, Bethesda, MD, USA). For contrast assessment, radiographs of an aluminum step wedge were obtained using the same PSP plate, X-ray devices, and acquisition parameters. The percentage of contrast variation was determined. The impacts of the devices on image quality were compared using the Student t-test, with a significance level of 5% (P<0.05). Results: Compared with the wall-mounted device, the handheld device produced radiographs with higher brightness and noise, as indicated by mean values of 6.57 (0.49) and 3.49 (0.02), respectively. Furthermore, it demonstrated lower uniformity and contrast, with respective means of 3.75 (0.02) and 35.48 (0.09) (P<0.05). Conclusion Radiographs obtained using a handheld X-ray device exhibit lower theoretical image quality than those acquired with a wall-mounted device.