Objective:To investigate the impact of four registration methods on the accuracy of virtual occlusal records (VOR) in intraoral scanning for implant restorations with multiple missing teeth.Methods:A mandibular model simulating clinical conditions with multiple missing teeth (right first molar, left second premolar, left first molar, left second molar) and a maxillary compete dentition model were mounted on a semi-adjustable articulator. Subsequently, twelve 0.5 mm stainless steel spheres were adhered to reference positions (16, 46, 13, 43, 23, 33, 25, 35, 26, 36, 27, 37) as fiducial markers. Following this, a laboratory scanner generated reference datasets by digitizing the models in maximum intercuspation (MIP). Meanwhile, ten maxillary and mandibular scans were acquired using an intraoral scanner, with all nonarticulated scans duplicated four times to ensure data consistency. Forty VOR intraoral scans were performed in MIP using four registration protocols: left-side, right-side, anterior, and bilateral registration ( n=10 per group), randomized via a computer-generated pseudo-random sequence. For measurement, linear distances (D16-46, D13-43, D23-33, D25-35, D26-36, D27-37, D16-46 represented the single-tooth defect position, whereas D25-35, D26-36, D27-37 reflected positions in free-end edentulism areas) between opposing markers were measured in a reverse engineering software, with deviations (ΔD) from the reference scan calculated to assess accuracy. Specifically, negative ΔD values indicated vertical dimension underestimation. Given that non-normally distributed data were analyzed using medians [interquartile ranges (IQR)], trueness (median ΔD) and precision (IQR) were evaluated. The interaction effect between the registration method and the position of the measurement items was evaluated by using the generalized linear model. The accuracy was compared overall by the Kruskal-Wallis test with the two-sided significance level of α=0.05. For pairwise comparisons, post-hoc tests were conducted by Dunn′s t-test with the Bonferroni correction for the significance level. Results:The accuracy of VOR was affected by registration method ( P<0.05), with a significant position×registration method interaction observed ( P<0.05). In particular, in all four groups, only the bilateral registration group showed trueness of less than 0.1 mm for both free-end edentulism and the single tooth defect, with ΔD16-46, ΔD25-35, ΔD26-36, and ΔD27-37 being 0.059 (0.015), -0.082 (0.052), -0.065 (0.032), -0.070 (0.050) mm, respectively. Moreover, trueness in free-end edentulism showed negative values across all groups, with the largest negative deviations observed in the right-side registration group, with ΔD25-35, ΔD26-36 and ΔD27-37 being -0.410 (0.174), -0.442 (0.225), -0.439 (0.262) mm, respectively. Conclusions:In fully digital workflows of implant restorations for mandibular free-end edentulism with multiple missing teeth, registration method critically influences VOR accuracy. While four registration methods exhibited underestimation of occlusal vertical dimension, bilateral registration achieved the highest accuracy.

Objective:To investigate the impact of four registration methods on the accuracy of virtual occlusal records (VOR) in intraoral scanning for implant restorations with multiple missing teeth.Methods:A mandibular model simulating clinical conditions with multiple missing teeth (right first molar, left second premolar, left first molar, left second molar) and a maxillary compete dentition model were mounted on a semi-adjustable articulator. Subsequently, twelve 0.5 mm stainless steel spheres were adhered to reference positions (16, 46, 13, 43, 23, 33, 25, 35, 26, 36, 27, 37) as fiducial markers. Following this, a laboratory scanner generated reference datasets by digitizing the models in maximum intercuspation (MIP). Meanwhile, ten maxillary and mandibular scans were acquired using an intraoral scanner, with all nonarticulated scans duplicated four times to ensure data consistency. Forty VOR intraoral scans were performed in MIP using four registration protocols: left-side, right-side, anterior, and bilateral registration ( n=10 per group), randomized via a computer-generated pseudo-random sequence. For measurement, linear distances (D16-46, D13-43, D23-33, D25-35, D26-36, D27-37, D16-46 represented the single-tooth defect position, whereas D25-35, D26-36, D27-37 reflected positions in free-end edentulism areas) between opposing markers were measured in a reverse engineering software, with deviations (ΔD) from the reference scan calculated to assess accuracy. Specifically, negative ΔD values indicated vertical dimension underestimation. Given that non-normally distributed data were analyzed using medians [interquartile ranges (IQR)], trueness (median ΔD) and precision (IQR) were evaluated. The interaction effect between the registration method and the position of the measurement items was evaluated by using the generalized linear model. The accuracy was compared overall by the Kruskal-Wallis test with the two-sided significance level of α=0.05. For pairwise comparisons, post-hoc tests were conducted by Dunn′s t-test with the Bonferroni correction for the significance level. Results:The accuracy of VOR was affected by registration method ( P<0.05), with a significant position×registration method interaction observed ( P<0.05). In particular, in all four groups, only the bilateral registration group showed trueness of less than 0.1 mm for both free-end edentulism and the single tooth defect, with ΔD16-46, ΔD25-35, ΔD26-36, and ΔD27-37 being 0.059 (0.015), -0.082 (0.052), -0.065 (0.032), -0.070 (0.050) mm, respectively. Moreover, trueness in free-end edentulism showed negative values across all groups, with the largest negative deviations observed in the right-side registration group, with ΔD25-35, ΔD26-36 and ΔD27-37 being -0.410 (0.174), -0.442 (0.225), -0.439 (0.262) mm, respectively. Conclusions:In fully digital workflows of implant restorations for mandibular free-end edentulism with multiple missing teeth, registration method critically influences VOR accuracy. While four registration methods exhibited underestimation of occlusal vertical dimension, bilateral registration achieved the highest accuracy.

Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. It is highly contagious and can cause death in severe cases. As reported by the World Health Organization (WHO), as of 6:36 pm Central European Summer Time (CEST), 12 August 2022, there had been 585 950 285 confirmed cases of COVID-19, including 6 425 422 deaths (WHO, 2022).
Humans ; COVID-19 ; SARS-CoV-2 ; Mental Health ; Cohort Studies ; Quality of Life ; China/epidemiology* ; Health Personnel ; Hospitals ; Lung

A 77-year-old man was admitted to our hospital at July 5th,2010 with an unexplained massive pericardial effusion for 10 years.With dyspnea for one month and normal vital signs without pulsus paradoxus,other physical examination included a small amount of moist rale,normal heart sounds,jugular vein engorgement,positive hepatojugular reflux,hepatosplenomegaly and pitting edema of the extremities.The patient had a complex past history with lymph node tuberculosis,primary artertial hypertension,polycythernia vera,chronic renal insufficiency and hypothyroidism (Hashimoto's thyroiditis),and moreover,received a high dose radiation of 31p in 1967. Family history is negative.The patient had no cardiac tamponade or pericardial constriction during 10 years,he received pericardiocentesis twice,and pericardial effusion was exudative with a high proportion of monocyte.There was no evidences of tuberculosis infection,hypothyroidism,malignant tumor,severe heart failure,uremia,trauma,severe bacterial or fungus infection,chronic myeloid leukemia or bone marrow fibrosis during the admission. The patient refused anti tuberculosis,indwelling catheter drainage or surgical therapy.In this rare case,the aetiology of chronic massive pericardial effusion is most probably chronic idiopathic recurrent pericarditis.

Objective To screen the optimum conditions carrying murine melanoma B16 cells in spaceflights without cares.MethodsMurine melanoma cells were cultured on micocarriers and grouped depending on cells concentration, serum concentration, microcarrier number and temperature.After 33 days, B16 cells were stained by Giemsa, observed with phase-contrast microscope and counted for surviving percentage.ResultsThe optimum conditions,in which the surviving percentages were 8% and 10%, were obtained in the experiments.B16 cells were carried in the 20th recoverable satellite orbiting 18 days under the optimum conditions. After recovering, 110 strain monocloned cells were survived and the surviving percentage was 1.1%.ConclusionThe optimum conditions carrying murine melanoma B16 cells in spaceflights without cares seems to be obtained,and it did improve the surviving time and percentage of cells in spaceflights without cares.