Reduction of the Number of Live Animals Used for Microsurgical Skill Acquisition: An Experimental Randomized Noninferiority Trial.

BACKGROUND: Live animals have been used for decades as one of the many training models for developing surgical skills. Microsurgery in particular relies on training for skill acquisition and maintenance, using live animal models, especially rats (murine models). Efforts are underway to reduce the number of rats sacrificed to achieve this objective. METHODS: A group of students with minimal microsurgical experience, after having gone through a basic microsurgical course, were randomly split into three equal groups, all three groups following a 24-week standard training program based on low- and medium-fidelity training models with standardized murine training days. In addition to the standard training regimen, each participant performed supplementary training on live rats every 4, 6, or 8 weeks. According to the training program, the procedures have been performed on chicken legs, flower petals, and rats, each procedure being blindly assessed and evaluated using validated models and scales. The primary evaluated outcome was the Stanford Microsurgery and Resident Training (SMaRT) scale result of the final rat anastomosis performed by each group, for which the tested hypothesis was one of noninferiority. The secondary outcomes were represented by the final rat anastomosis time, final chicken leg anastomosis result and time, and the final petal score. RESULTS: After the 24th week, no differences were observed between the three groups regarding their microsurgical skills, as measured by the aforementioned surgical outcomes. All participants improved significantly during the study (mean [standard deviation] 19 ± 4 points on the SMaRT scale), with no significant differences between the groups, p < 0.001 for noninferiority. CONCLUSION: A training regimen based on low- and moderate-fidelity models, with the addition of training on a live rat every 8 weeks was noninferior to a training regimen that used a live rat every 6 weeks and also noninferior to a training regimen that used a live rat every 4 weeks.

Color compatibility between dental structures and three different types of ceramic systems.

BACKGROUND: To assess color compatibility between dental structures (human enamel and dentine) and three different types of ceramic systems. METHODS: Samples (1 and 2 mm-thick) of extracted tooth (containing dentine and enamel areas) and three ceramic systems with different shades and opacities (HT-High Translucent, T-Translucent) were prepared for this study: Vita Suprinity-VS (HT, T; A1, A2, A3, A3.5, B2, C2, D2) (Vita Zahnfabrik); Vita Enamic-VE (HT, T; 1M1, 1M2, 2M2, 3M2) (Vita Zahnfabrik) and Noritake Super Porcelain EX-3-NKT (A1, A2, A3, A3.5, B2, C2, D2) (Kuraray Noritake Dental). Reflectance measurements of all samples were performed over black backgrounds using a non-contact spectroradiometer (SpectraScan PR-670, Photo Research) under a CIE 45°/0° geometry. CIE L*a*b* color parameters were measured and CIELAB/CIEDE2000 color differences (ΔE00/ΔE*ab) and corresponding Coverage Error (CE) of ceramic system for dentine or enamel samples were calculated. Color data was analyzed using one-way ANOVA and post-hoc multiple comparisons tests. CE values were interpreted by comparisons with available 50:50% acceptability color threshold (AT) for dentistry. RESULTS: Statistically significant differences in lightness were found among all ceramic systems and human dentine (p < 0.001), while no significant differences were registered between enamel and VSHT, T and VEHT. 1 mm dentine showed no statistical differences with VST and VSHT for a* coordinate, while 2 mm dentine showed no significant differences (p > 0.05) with VEHT. Thin samples (1 mm) of dentine and enamel showed significant statistical differences (p < 0.05) for b* coordinate with less translucent materials (NKT, VET and VST). For dentine samples, none of the ceramic materials provided a CE lower than AT. VSHT provided the best CE for 1 mm-thick (CE00 = 1.7, CEab = 1.9) and for 2 mm-thick (CE00 = 2.3; CEab = 2.5) enamel samples. CONCLUSIONS: Color coordinates of evaluated esthetic ceramic systems were statistically different from those of human dentine in almost all cases. The evaluated ZrO2 lithium silicate glass-ceramic (VS), with its two levels of translucency, provided lower CE values with human enamel samples while conventional feldspathic ceramic (NKT) and hybrid ceramic systems (VE) demonstrated a better color compatibility with dentin samples.

Cardiac Arrhythmias and Electrocardiogram Modifications in Non-Alcoholic Fatty Liver Disease. A Systematic Review.

BACKGROUND AND AIMS: Recent studies have evaluated the relationship associating non-alcoholic fatty liver disease (NAFLD) with several electrocardiogram (ECG) findings, but the results have been inconsistent. The aim of this systematic review is to assess the association between NAFLD with ECG modifications. METHODS: We conducted a systematic search on PubMed with predefined keywords identifying observational studies published till 22 February 2019 with NAFLD diagnosed either by biopsy, imaging, surrogate markers or ICD code and ECG findings by either a standard ECG, 24-hour Holter ECG or ICD code. Quality assessment was performed using the quality assessment tools from the National Heart, Lung, and Blood Institute. RESULTS: A total of 20 observational studies (1 case-control, 4 cohort, 15 cross-sectional studies, 401,745 individuals) were included. Twelve studies evaluated cardiac arrhythmias in NAFLD subjects, out of which 10 evaluated atrial fibrillation (AF). Although results were inconsistent, most studies rated as "good" demonstrated that hepatic steatosis was independently associated with an increased risk for prevalent AF in NAFLD patients. Diabetic patients with NAFLD were associated with an increased risk of ventricular arrhythmias in only one study rated as "good". Two studies rated as "good" demonstrated that hepatic steatosis was associated with a prolonged QTc interval. Four studies supported the association between cardiac conduction abnormalities and NAFLD, out of which two were rated as "good". Two studies assessed ECG modifications of ischemic heart disease (IHD), but only one having a "good" rating confirmed this independent association. CONCLUSIONS: Studies of high quality and with low risk of bias demonstrated that NAFLD is independently associated with AF, a prolonged QTc interval, bundle branch and atrioventricular blocks. Diabetic patients with NAFLD present an increased risk for developing ventricular arrhythmias.

Effect of glazing on translucency, color, and surface roughness of monolithic zirconia materials.

OBJECTIVES: To assess the effect of material, thickness and glazing upon the color, translucency, and roughness of monolithic zirconia. MATERIALS AND METHODS: Sixty discs (0.8, 1.5, and 2 mm thickness) were fabricated from A1 translucent zirconia (IPS e.max ZirCAD/MT, Katana/HT, Vita YZ/HT, Cercon/HT) and glazed. Roughness (Ra) was assessed with a profilometer and color coordinates were measured with a spectrophotometer on a black, white, and tooth-shaded background before and after glazing. Relative translucency parameter (RTP), color differences (CIEDE2000) and differences in translucencies between materials, before and after glazing were calculated. RTP, Ra, color differences were statistically analyzed using ANOVA. Any significant interaction between factors was further analyzed using Tukey's HSD. RESULTS: RTP values were significantly different between materials (P < .001) and thicknesses (P < .001), with the interaction effect between material type and thickness, also significant (P < .001). However, glazing did not have a significant effect on RTP values (P = .782). Color differences resulted after glazing were significantly different between materials (P < .001), and thicknesses (P < .001) with the interaction effect also significant (P < .001). Glazing influenced roughness, Ra decreasing for all materials (P < .001). CONCLUSIONS: As a result of glazing, only color changes were statistically significant. Translucency varied among brands of precolored monolithic zirconia; the differences increased for greater thicknesses. CLINICAL SIGNIFICANCE: Glazing is an important step in the technological process of ceramic restorations; however, it can influence the final optical appearance of the restoration as color changes could be expected after the application of the glaze.

Dentin translucency and color evaluation in human incisors, canines, and molars.

STATEMENT OF PROBLEM: For restorations with excellent esthetics, an understanding of the optical properties of human dentin is needed. Little information is available on the translucency and color parameters of dentin and its relationship to tooth type and position. PURPOSE: The purpose of this in vitro study was to investigate the translucency and CIELab color coordinates of human dentin in both anterior (incisors and canines) and posterior teeth (molars) by using spectrophotometric and spectroradiometric assessment methods. MATERIAL AND METHODS: Uniformly thick specimens (2 mm) of midcoronal human dentin were taken from 33 central and lateral incisors, 7 canines, and 33 molars (all maxillary teeth). The CIELab color coordinates were measured with a clinical spectrophotometer (Easyshade Compact) and a noncontact spectroradiometer (SpectraScan PR-704). The translucency parameter (TP) was calculated. Bland-Altman plots and Wilcoxon signed rank tests for paired samples were used to assess the agreement of the 2 measurement techniques. The differences between anterior and posterior dentin specimens regarding color coordinates and the translucency parameter were analyzed using Mann-Whitney-Wilcoxon rank sum tests. RESULTS: Statistically significant differences between spectrophotometric and spectroradiometric measurements of the TP and CIELab color coordinates were found in both groups of dentin specimens (P<.05). TP values of molar dentin specimens were significantly higher than those of the anterior ones, regardless of the assessment method (P<.001). Dentin specimens of the anterior teeth exhibited higher L∗ values but lower a∗ and b∗ values on both black and white backgrounds compared with molar dentin specimens. CONCLUSIONS: The dentin of anterior teeth was found to be lighter but less translucent and less chromatic than in molars, regardless of the assessment method used.

Susceptibility of 100 filamentous fungi: comparison of two diffusion methods, Neo-Sensitabs and E-test, for amphotericin B, caspofungin, itraconazole, voriconazole and posaconazole.

We compared the E-test method to that of the Neo-Sensitabs tablet diffusion assay for evaluating the in vitro susceptibility of 100 clinical isolates of filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp., zygomycetes and other molds) to amphotericin B, itraconazole, voriconazole, caspofungin, and posaconazole. We determined the categorical agreement level between E-test minimum inhibitory concentrations (MIC) and tablet end-points, as opposed to the following disagreement parameters: very major error - resistant parameter (R) in E-test and susceptible (S) in tablet; major error - S by E-test and R by tablet; minor error - shifts between S and susceptible dose-dependent (S-DD) or S-DD and R. We also performed linear regression analyses and computed Pearson's correlation coefficients (R values) between the log transforms of MICs and the inhibition zone diameters of the five studied antifungal agents. For itraconazole we obtained 97% categorical agreement and R = -0.727. Categorical agreement for caspofungin and voriconazole was 96% and R =-0.821 and R = -0.789, respectively. For posaconazole the categorical agreement was 94% and R =-0.743. Amphotericin B exhibited a lower degree of agreement (76%, R = -0.672), especially in studies of Aspergillus spp. Our results suggest a potential value of the Neo-Sensitabs assay for in vitro susceptibility testing of molds to itraconazole, voriconazole, caspofungin and posaconazole, while amphotericin B exhibited an overall lower degree of agreement.