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ObjectiveTo investigate the degree of conversion (DC), Martens hardness (HM), elastic indentation modulus (EIT), and biaxial flexural strength (BFS) of six dual-polymerizing resin composite luting materials initially and after 2 and 7 days of aging.Materials and methodsSpecimens fabricated from Bifix QM (BIF; VOCO), Calibra Ceram (CAL; Dentsply Sirona), DuoCem (DUO; Coltène/Whaledent), G-CEM LinkForce (GCE; GC Europe), PANAVIA V5 (PAN; Kuraray Europe), and Variolink Esthetic DC (VAR; Ivoclar Vivadent) (n = 12 per material) were light-polymerized through 1 mm thick discs (Celtra Duo, Dentsply Sirona). DC, HM, and EIT were recorded directly after fabrication, and after 2 and 7 days of aging. As a final test, BFS was measured. Univariate ANOVAs, Kruskal–Wallis, Mann–Whitney U, Friedman, and Wilcoxon tests, and Weibull modulus were computed (p < 0.05).ResultsWhile CAL presented low DC, HM, EIT, and BFS values, DUO and BIF showed high results. Highest Weibull moduli were observed for VAR and DUO. DC and Martens parameters increased between the initial measurement and 2 days of aging, while aging for 7 days provided no further improvement.ConclusionsThe choice of dual-polymerizing resin composite luting material plays an important role regarding chemical and mechanical properties, especially with patients sensitive to toxicological issues. DUO may be recommended for bonding fixed dental prostheses, as it demonstrated significantly highest and reliable results regarding DC, HM, and BFS. As DC and HM showed an increase in the first 48 h, it may be assumed that the polymerization reaction is not completed directly after initial polymerization, which is of practical importance to dentists and patients.Clinical relevanceThe chemical and mechanical properties of dual-polymerizing resin composite luting materials influence the overall stability and long-term performance of the restoration.

ObjectivesTo investigate the chemical (degree of conversion (DC)) and mechanical properties (Martens hardness (HM), elastic indentation modulus (EIT), and biaxial flexural strength (BFS)) of four dual-polymerizing resin composite core build-up materials after light- and self-polymerization.Materials and methodsRound specimens with a diameter of 12 mm and a thickness of 1.5 mm were manufactured from CLEARFIL DC CORE PLUS (CLE; Kuraray), core·X flow (COR; Dentsply Sirona), MultiCore Flow (MUL; Ivoclar Vivadent), and Rebilda DC (REB; VOCO) (N = 96, n = 24/material). Half of the specimens were light-polymerized (Elipar DeepCure-S, 3 M), while the other half cured by self-polymerization (n = 12/group). Immediately after fabrication, the DC, HM, EIT, and BFS were determined. Data was analyzed using Kolmogorov–Smirnov, Mann–Whitney U, and Kruskal–Wallis tests, Spearman’s correlation, and Weibull statistics (p < 0.05).ResultsLight-polymerization either led to similar EIT (MUL; p = 0.119) and BFS (MUL and REB; p = 0.094–0.326) values or higher DC, HM, EIT, and BFS results (all other groups; p < 0.001–0.009). When compared with the other materials, COR showed a high DC (p < 0.001) and HM (p < 0.001) after self-polymerization and the highest BFS (p = 0.020) and Weibull modulus after light-polymerization. Positive correlations between all four tested parameters (R = 0.527–0.963, p < 0.001) were found.ConclusionsFor the tested resin composite core build-up materials, light-polymerization led to similar or superior values for the degree of conversion, Martens hardness, elastic indentation modulus, and biaxial flexural strength than observed after self-polymerization. Among the tested materials, COR should represent the resin composite core build-up material of choice due to its high chemical (degree of conversion) and mechanical (Martens hardness, elastic indentation modulus, and biaxial flexural strength) properties and its high reliability after light-polymerization. The examined chemical and mechanical properties showed a positive correlation.Clinical relevanceThe chemical and mechanical performance of dual-polymerizing resin composite core build-up materials is significantly affected by the chosen polymerization mode.

Abstract ObjectivesThe aim of this study is to investigate the influence of the material and corresponding sintering protocol, layer thickness, and aging on the two-body wear (2BW) and fracture load (FL) of 4Y-TZP crowns.Materials and methodsMulti-layer 4Y-TZP crowns in three thicknesses (0.5 mm/1.0 mm/1.5 mm) were sintered by high-speed (Zolid RS) or conventional (Zolid Gen-X) sintering. 2BW of ceramic and enamel antagonist after aging (1,200,000 mechanical-, 6000 thermal-cycles) was determined by 3D-scanning before and after aging and subsequent matching to determine volume and height loss (6 subgroups, n = 16/subgroup). FL was examined initially and after aging (12 subgroups, n = 16/subgroup). Fractographic analyses were performed using light-microscope imaging. Global univariate analysis of variance, one-way ANOVA, linear regression, Spearman’s correlation, Kolgomorov–Smirnov, Mann–Whitney U, and t test were computed (alpha = 0.05). Weibull moduli were determined. Fracture types were analyzed using Ciba Geigy table.ResultsMaterial/sintering protocol did not influence 2BW (crowns: p = 0.908, antagonists: p = 0.059). High-speed sintered Zolid RS presented similar (p = 0.325–0.633) or reduced (p < 0.001–0.047) FL as Zolid Gen-X. Both 4Y-TZPs showed an increased FL with an increasing thickness (0.5(797.3–1429 N) < 1.0(2087–2634 N) < 1.5(2683–3715 N)mm; p < 0.001). For most groups, aging negatively impacted FL (p < 0.001–0.002). Five 0.5 mm specimens fractured, four showed cracks during and after aging.ConclusionsHigh-speed sintered crowns with a minimum thickness of 1.0 mm showed sufficient mechanical properties to withstand masticatory forces, even after a simulated aging period of 5 years.Clinical relevanceDespite the manufacturer indicating a thickness of 0.5 mm to be suitable for single crowns, a minimum thickness of 1.0 mm should be used to ensure long-term satisfactory results.

The connection between Pediatric Inflammatory Multisystem Syndrome (PIMS) and Kawasaki Disease (KD) is not yet fully understood. Using the same national registry, clinical features and outcome of children hospitalized in Germany, and Innsbruck (Austria) were compared. Reported to the registry were 395 PIMS and 69 KD hospitalized patients. Patient age in PIMS cases was higher than in KD cases (median 7 [IQR 4–11] vs. 3 [IQR 1–4] years). A majority of both PIMS and KD patients were male and without comorbidities. PIMS patients more frequently presented with organ dysfunction, with the gastrointestinal (80%), cardiovascular (74%), and respiratory (52%) systems being most commonly affected. By contrast, KD patients more often displayed dermatological (99% vs. 68%) and mucosal changes (94% vs. 64%), plus cervical lymph node swelling (51% vs. 34%). Intensive care admission (48% vs. 19%), pulmonary support (32% vs. 10%), and use of inotropes/vasodilators (28% vs. 3%) were higher among PIMS cases. No patients died. Upon patient discharge, potentially irreversible sequelae—mainly cardiovascular—were reported (7% PIMS vs. 12% KD). Despite differences in age distribution and disease severity, PIMS and KD cases shared many common clinical and prognostic characteristics. This supports the hypothesis that the two entities represent a syndrome continuum.

Due to the growing demand for lightweight solutions in a wide range of industries, the selection and combination of various materials is becoming more and more important. As a result, the need for suitable joining technologies is increasing along with it. Within the DFG research group \"Schwarz-Silber\" (\"black-silver\"), Fraunhofer IFAM is investigating so-called transitional structures in cooperation with the University of Bremen. In this process, glass fiber structures are integrated into aluminum by a high pressure die casting process. These structures are used for the electrochemical insulation between aluminum and carbon fiber textiles, which are connected by textile processes in a subsequent production step. A solid hybrid structure is finally achieved through a resin-impregnation process. The key challenges are the positioning, pre-tensioning and infiltration of the glass fiber structures within the high pressure die casting process. In order to meet these challenges, a customized die casting tool was developed within the project. With the aid of mold-filling simulations, the die system of the die casting tool was optimized to achieve better infiltration of the fiber bundles and to additionally support the position of the glass fibers in the casting process. After the design of the molding tool, the implementation was carried out in collaboration with a toolmaker. In subsequent, up-to-date investigations, the positioning and infiltration of different variants of glass fiber structures is evaluated. The results are compared with previous attempts to position and infiltrate the glass fiber structures to assess the effect of the optimized newly designed tool.