Background: Aortic regurgitation (AR) has an important impact on myocardial mechanics and recent studies have proved the value of global longitudinal strain (GLS) in the assessment of its severity and prognosis. Our purpose was to assess if the direct impact of the regurgitant jet on the myocardial wall could affect regional longitudinal strain. Methods: Eighty patients with chronic moderate/severe AR were retrospectively studied. Patients were considered to have a jet-related longitudinal strain reduction when the myocardial segments directly impacted by the jet had their longitudinal strain reduced by at least 30% compared to nonaffected segments. AR severity, left ventricular (LV) size and function were compared according to the presence/absence of this regional pattern. For those who underwent surgery, postoperative regional and global LV function was also analyzed. Results: A pattern of regional longitudinal strain impairment was identified in 43% of patients, with a regional reduction (in median) of 10 percentage points in absolute strain values in the segments impacted by the jet, compared to nonaffected segments. In the subgroup who underwent surgery, this pattern became attenuated after surgery.Patients with regional longitudinal strain impairment were less likely to improve GLS after surgery (10% vs. 38% improved GLS by at least 2.5%, P = 0.049). Conclusions To our knowledge, this study identifies for the first time, a link between the location of the impact of the regurgitant jet in AR and regional longitudinal strain impairment. The presence of this regional pattern might be associated with worse postoperative LV recovery.

Background: Aortic regurgitation (AR) has an important impact on myocardial mechanics and recent studies have proved the value of global longitudinal strain (GLS) in the assessment of its severity and prognosis. Our purpose was to assess if the direct impact of the regurgitant jet on the myocardial wall could affect regional longitudinal strain. Methods: Eighty patients with chronic moderate/severe AR were retrospectively studied. Patients were considered to have a jet-related longitudinal strain reduction when the myocardial segments directly impacted by the jet had their longitudinal strain reduced by at least 30% compared to nonaffected segments. AR severity, left ventricular (LV) size and function were compared according to the presence/absence of this regional pattern. For those who underwent surgery, postoperative regional and global LV function was also analyzed. Results: A pattern of regional longitudinal strain impairment was identified in 43% of patients, with a regional reduction (in median) of 10 percentage points in absolute strain values in the segments impacted by the jet, compared to nonaffected segments. In the subgroup who underwent surgery, this pattern became attenuated after surgery.Patients with regional longitudinal strain impairment were less likely to improve GLS after surgery (10% vs. 38% improved GLS by at least 2.5%, P = 0.049). Conclusions To our knowledge, this study identifies for the first time, a link between the location of the impact of the regurgitant jet in AR and regional longitudinal strain impairment. The presence of this regional pattern might be associated with worse postoperative LV recovery.

Background: Aortic regurgitation (AR) has an important impact on myocardial mechanics and recent studies have proved the value of global longitudinal strain (GLS) in the assessment of its severity and prognosis. Our purpose was to assess if the direct impact of the regurgitant jet on the myocardial wall could affect regional longitudinal strain. Methods: Eighty patients with chronic moderate/severe AR were retrospectively studied. Patients were considered to have a jet-related longitudinal strain reduction when the myocardial segments directly impacted by the jet had their longitudinal strain reduced by at least 30% compared to nonaffected segments. AR severity, left ventricular (LV) size and function were compared according to the presence/absence of this regional pattern. For those who underwent surgery, postoperative regional and global LV function was also analyzed. Results: A pattern of regional longitudinal strain impairment was identified in 43% of patients, with a regional reduction (in median) of 10 percentage points in absolute strain values in the segments impacted by the jet, compared to nonaffected segments. In the subgroup who underwent surgery, this pattern became attenuated after surgery.Patients with regional longitudinal strain impairment were less likely to improve GLS after surgery (10% vs. 38% improved GLS by at least 2.5%, P = 0.049). Conclusions To our knowledge, this study identifies for the first time, a link between the location of the impact of the regurgitant jet in AR and regional longitudinal strain impairment. The presence of this regional pattern might be associated with worse postoperative LV recovery.

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.

The coronavirus disease 2019 (COVID-19) pandemic has affected all Canadian families, with some impacted differently than others. Our study aims to: (1) determine the prevalence and transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among Canadian families, (2) identify predictors of infection susceptibility and severity of SARS-CoV-2, and (3) identify health and psychosocial impacts of the COVID-19 pandemic. This study builds upon the CHILD Cohort Study, an ongoing multi-ethnic general population prospective cohort consisting of 3,454 Canadian families with children born in Vancouver, Edmonton, Manitoba, and Toronto between 2009 and 2012. During the pandemic, CHILD households were invited to participate in the CHILD COVID-19 Add-On Study involving: (1) brief biweekly surveys about COVID-19 symptoms and testing; (2) quarterly questionnaires assessing COVID-19 exposure and testing, vaccination status, physical and mental health, and pandemic-driven life changes; and (3) in-home biological sampling kits to collect blood and stool. In total, 1,462 households (5,378 participants) consented to the CHILD COVID-19 Add-On Study: 2,803 children (mean±standard deviation [SD], 9.0±2.7 years; range, 0-17 years) and 2,576 adults (mean±SD, 43.0±6.5 years; range, 18-85 years). We will leverage the wealth of pre-pandemic CHILD data to identify risk and resilience factors for susceptibility and severity to the direct and indirect pandemic effects. Our short-term findings will inform key stakeholders and knowledge users to shape current and future pandemic responses. Additionally, this study provides a unique resource to study the long-term impacts of the pandemic as the CHILD Cohort Study continues.

Objectives: This study evaluated the effect of different nanoparticulated zinc oxide (nanoZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC). Materials and Methods: The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventionalZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (Rad ), setting time (Set ), dimensional change (Dc ), solubility (Sol ), compressive strength (Cst ), and pH were evaluated. The nanoZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy.Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05). Results: The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest R ad mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the S et (p < 0.05) and lower values of D c at 24 hours (p < 0.05). The C st was higher for G4, with a significant difference for the other groups (p < 0.05). The S ol did not present significant differences among groups (p > 0.05). Conclusions The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.

Objectives: This study evaluated the effects of Biodentine (BD), Bio-C Repair (BCR), and mineral trioxide aggregate (MTA) plug on the fracture resistance of simulated immature teeth with replacement root resorption (RRR) and in vitro-induced osteoclastogenesis. Materials and Methods: Sixty bovine incisors simulating immature teeth and RRR were divided into 5 groups: BD and BCR groups, with samples completely filled with the respective materials; MTA group, which utilized a 3-mm apical MTA plug; RRR group, which received no root canal filling; and normal periodontal ligament (PL) group, which had no RRR and no root canal filling. All the teeth underwent cycling loading, and compression strength testing was performed using a universal testing machine. RAW 264.7 macrophages were treated with 1:16 extracts of BD, BCR, and MTA containing receptor activator of nuclear factor-kappa B ligand (RANKL) for 5 days. RANKL-induced osteoclast differentiation was assessed by staining with tartrate-resistant acid phosphatase. The fracture load and osteoclast number were analyzed using 1-way ANOVA and Tukey’s test (α = 0.05). Results: No significant difference in fracture resistance was observed among the groups (p > 0.05). All materials similarly inhibited osteoclastogenesis (p > 0.05), except for BCR, which led to a lower percentage of osteoclasts than did MTA (p < 0.0001). Conclusions The treatment options for non-vital immature teeth with RRR did not strengthen the teeth and promoted a similar resistance to fractures in all cases. BD, MTA, and BCR showed inhibitory effects on osteoclast differentiation, with BCR yielding improved results compared to the other materials.