Purpose: The aim of this study was to evaluate the influence of different cone-beam computed tomography (CBCT) acquisition protocols on reducing the effective radiation dose while maintaining image quality. Materials and Methods: The effective dose emitted by a CBCT device was calculated using thermoluminescent dosimeters placed in a Rando Alderson phantom. Image quality was assessed by 3 experienced evaluators. The relation-ship between image quality and confidence was evaluated using the Fisher exact test, and the agreement among raters was assessed using the kappa test. Multiple linear regression analysis was performed to investigate whether the technical parameters could predict the effective dose. P-values<0.05 were considered to indicate statistical significance. Results: The optimized protocol (3 mA, 99 kVp, and 450 projection images) demonstrated good image quality and a lower effective dose for radiation-sensitive organs. Image quality and confidence had consistent values for all structures (P<0.05). Multiple linear regression analysis resulted in a statistically significant model. The milliamperage (b = 0.504; t = 3.406; P = 0.027), kilovoltage peak (b = 0.589; t = 3.979; P = 0.016) and number of projection images (b = 0.557; t = 3.762; P = 0.020) were predictors of the effective dose. Conclusion Optimized CBCT acquisition protocols can significantly reduce the effective radiation dose while maintaining acceptable image quality by adjusting the milliamperage and projection images.

Ultrasonography is highly accurate for evaluating soft tissues. Given that minimally invasive aesthetic procedures are on the rise, complications have become more prevalent. Thus, ultrasonography holds promise for assisting in the diagnosis and management of complications arising from these interventions. This report highlights the importance of ultrasonography in the treatment of complications caused by hyaluronic acid injection. A patient visited a dentaloffice 24 hours after hyaluronic acid application, presenting pain and bruising in the middle and inferior thirds of theface on the right side. To evaluate blood vessels, the surgeon used Doppler-mode ultrasonography, which enabled the precise application of hyaluronidase to reestablish blood perfusion and preserve adjacent structures. Therefore, to avoid severe outcomes, such as necrosis or even amaurosis, the use of ultrasonography is suggested, improving the precision and safety of these procedures.

Kidneys are sensitive to disturbances in oxygen homeostasis. Hypoxia and activation of the hypoxia-inducible factor (HIF) pathway alter the expression of genes involved in the metabolism of renal and immune cells, interfering with their functioning. Whether the transcriptional activity of HIF protects the kidneys or participates in the pathogenesis of renal diseases is unclear. Several studies have indicated that HIF signaling promotes fibrosis in experimental models of kidney disease. Other reports showed a protective effect of HIF activation on kidney inflammation and injury. In addition to the direct effect of HIF on the kidneys, experimental evidence indicates that HIF-mediated metabolic shift activates inflammatory cells, supporting the HIF cascade as a link between lung or gut damage and worsening of renal disease. Although hypoxia and HIF activation are present in several scenarios of renal diseases, further investigations are needed to clarify whether interfering with the HIF pathway is beneficial in different pathological contexts.

Objective: To analyze the microimplant (MI) displacement pattern on treatment with a maxillary skeletal expander (MSE) using cone-beam computed tomography (CBCT). Methods: Thirty-nine participants (12 males and 27 females; mean age, 18.2 ± 4.2 years) were treated successfully with the MSE II appliance. Their pre- and post-expansion CBCT data were superimposed. The pre- and post-expansion anterior and posterior inter-MI angles, neck and apical inter-MI distance, plate angle, palatal bone thickness at the MI positions, and suture opening at the MI positions were measured and compared. Results: The jackscrew plate was slightly bent in both anterior and posterior areas. There was no significant difference in the extent of suture opening between the anterior and posterior MIs (P > 0.05). The posterior MI to hemiplate line was greater than that anteriorly (P < 0.05). The apical distance between the posterior MIs was greater than that anteriorly (P < 0.05). The palatal thickness at the anterior MIs was significantly greater than that posteriorly (P > 0.01). Conclusions In the coronal plane, the angulation between the anterior MIs in relation to the jackscrew plate was greater than that between the posterior MIs owing to the differential palatal bone thickness.

Purpose: The objective of this study was to assess the fractal dimension, lacunarity, trabecular microarchitecture parameters, and cortical linear measurements in the mandibles of male and female individuals to identify differences between them. Materials and Methods: In total, 116 cone-beam computed tomography scans of healthy individuals of different ages (57 men and 59 women, aged between 20 and 60 years) were selected. The following bone parameters were measured: 1) buccal, lingual, and basal cortical bone thickness in 5 standard parasagittal sections (the midline, the left and right sides of the lower lateral incisors, and the left and right sides of the lower canines); 2) the bone volume fraction of 10 sequential axial sections from each patient by creating a volume of interest in the area between the lower canines; and 3) fractal dimension and lacunarity using grayscale images of the same region of the volume ofinterest in the anterior mandible. Spearman correlation coefficients and the Mann-Whitney test were used. Results: A significant and positive correlation was found between age and cortical thickness, especially in the region of the central incisors. Significant differences between sexes in terms of fractal dimension, lacunarity, and bone volume were found. Women revealed lower fractal dimension values and higher lacunarity and bone volume ratiovalues than men. Conclusion Fractal dimension, lacunarity, trabecular bone volume, and cortical thickness were different between men and women of different ages. (Imaging Sci Dent 2023; 53: 153-9)

Purpose: This study assessed the intensity of artifacts produced by 2 metal posts, 2 cements, and different exposure parameters using 2 cone-beam computed tomography (CBCT) units. Materials and Methods: The sample was composed of 20 single-rooted premolars, divided into 4 groups: Ni-Cr/ zinc phosphate, Ni-Cr/resin cement, Ag-Pd/zinc phosphate, and Ag-Pd/resin cement. Samples were scanned before and after post insertion and cementation using a CS9000 3D scanner with 4 exposure parameters (85/90 kV and 6.3/10 mA) and an i-CAT scanner with 120 kV and 5 mA. The presence of artifacts was assessed subjectively by 2 observers and objectively by a trained observer using ImageJ software. The Mann-Whitney, Wilcoxon, weighted kappa, and chi-square tests were used to assess data at a 95% confidence level (α<0.05). Results: In the subjective analyses, AgPd presented more hypodense and hyperdense lines than NiCr (P<0.05), and more hypodense halos were found using i-CAT (P<0.05) than using CS9000 3D. More hypodense halos, hypodense lines, and hyperdense lines were observed at 10 mA than at 6.3 mA (P<0.05). More hypodense halos were observed at 85 kV than at 90 kV (P<0.05). CS9000 3D presented more hypodense and hyperdense lines than i-CAT (P<0.05). In the objective analyses, AgPd presented higher percentages of hyperdense and hypodense artifacts than NiCr (P<0.05). Zinc phosphate cement presented higher hyperdense artifact percentages on CS9000 3D scans (P<0.05). CS9000 3D presented higher artifact percentages than i-CAT (P<0.05). Conclusion High-atomic-number alloys, higher tube current, and lower tube voltage may increase the artifacts present in CBCT images. (Imaging Sci Dent 2023; 53: 127-35)

Objectives: This study aimed to evaluate the surrounding and underlying shades’ effect on the color adjustment potential (CAP) of a single-shade composite used in a thin layer. Materials and Methods: Cylinder specimens (1.0 mm thick) were built with the Vittra APS Unique composite, surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built only with the control composites. Each specimen’s color was measured against white and black backgrounds or the simple control specimens with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WID ) and translucency parameters (TP 00 ) were calculated for simple specimens. Differences (ΔE00 ) in color between the simple/dual specimens and the controls were calculated. The CAP was calculated based on the ratios between data from simple and dual specimens. Results: The Vittra APS Unique composite showed higher WID and TP00 values than the controls. The highest values of ΔE00 were observed among simple specimens. The color measurements of Vittra APS Unique (simple or dual) against the control specimens presented the lowest color differences. Only surrounding the single-shade composite with a shaded composite barely impacted the ΔE00 . The highest CAP values were obtained using a shaded composite under simple or dual specimens. Conclusions The CAP of Vittra APS Unique was strongly affected by the underlying shade, while surrounding this composite with a shaded one barely affected its color adjustment.

In late 2019, an outbreak of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) initiated in Wuhan, Hubei province, China. The major clinical symptoms described for coronavirus disease (COVID-19) include respiratory distress and pneumonia in severe cases, and some patients may experience gastrointestinal impairments. In accordance, viral RNA or live infectious virus have been detected in feces of patients with COVID-19. Binding of SARS-CoV-2 to the angiotensin‐converting enzyme 2 (ACE2) is a vital pathway for the virus entry into human cells, including those of the respiratory mucosa, esophageal epithelium as well as the absorptive enterocytes from ileum and colon. The interaction between SARS-CoV-2 and ACE2 receptor may decrease the receptor expression and disrupt the function of B0AT1 transporter influencing the diarrhea observed in COVID-19 patients. In this context, a fecal-oral transmission route has been considered and points out a role for the digestive tract in disease transmission and severity. Here, in order to further understand the impact of COVID-19 in human physiology, the cellular and molecular mechanisms of SARS-CoV-2 infection and disease severity are discussed in the context of gastrointestinal disturbances.

Purpose: This study was performed to compare the ability of limited- and large-volume cone-beam computed tomography (CBCT) to display isthmuses in the apical root canals of mandibular molars. Materials and Methods: Forty human mandibular first molars with isthmuses in the apical 3 mm of mesial roots were scanned by micro-computed tomography (micro-CT), and their thickness, area, and length were recorded. The samples were examined using 2 CBCT systems, using the smallest voxels and field of view available for each device. The Mann-Whitney, Friedman, and Dunn multiple comparison tests were performed (α=0.05). Results: The 3D Accuitomo 170 and i-Cat devices detected 77.5% and 75.0% of isthmuses, respectively (P>0.05). For length measurements, there were significant differences between micro-CT and both 3D Accuitomo 170 and i-Cat (P<0.05). Conclusion Both CBCT systems performed similarly and did not detect isthmuses in the apical third in some cases. CBCT still does not equal the performance of micro-CT in isthmus detection, but it is nonetheless a valuable tool in endodontic practice.

Purpose: This study evaluated the influence of a metal artifact reduction (MAR) tool in a cone-beam computed tomography (CBCT) device on the diagnosis of vertical root fractures (VRFs) in teeth with different root filling materials. Materials and Methods: Forty-five extracted human premolars were classified into three subgroups; 1) no filling; 2) gutta-percha; and 3) metallic post. CBCT images were acquired using an Orthopantomograph 300 unit with and without a MAR tool. Subsequently, the same teeth were fractured, and new CBCT scans were obtained with and without MAR. Two oral radiologists evaluated the images regarding the presence or absence of VRF. Receiver operating characteristic (ROC) curves and diagnostic tests were performed. Results: The overall area under the curve values were 0.695 for CBCT with MAR and 0.789 for CBCT without MAR. The MAR tool negatively influenced the overall diagnosis of VRFs in all tested subgroups, with lower accuracy (0.45–0.72), sensitivity (0.6–0.67), and specificity (0.23–0.8) than were found for the images without MAR. In the latter group, the accuracy, sensitivity, and specificity values were 0.68–0.77, 0.67–083, and 0.53–087, respectively. However, no significant difference was found between images with and without MAR for the no filling and gutta-percha subgroups (P>0.05). In the metallic post subgroup, CBCT showed a significant difference according to MAR use (P<0.05). Conclusion The OP 300 MAR tool negatively influenced the detection of VRFs in teeth with no root canal filling, gutta-percha, or metallic posts. Teeth with metallic posts suffered the most from the negative impact of MAR.