Objectives: Antiadherent and antibacterial effects of certain plant extracts have been proven to be beneficial in preventive dentistry. In the present in situ/in vitro crossover study, the impact of plant extracts rich in polyphenols on the erosion-protective properties of the in situ pellicle was evaluated. Methods: Individual splints were prepared for 12 subjects for intraoral exposure of bovine enamel specimens. Following formation of a 1-min pellicle, watery plant extracts (leaves of the wild form of Ribes nigrum, the wild form of Origanum as well as a combination of both) were administered for 10 min in situ. Alternatively, a mouth rinse with fluorides (Elmex Kariesschutz) was performed for 1 min. After further oral exposure for 19/28 min, respectively, slabs were removed and incubated with HCl in vitro over 120 s (pH 2, 2.3, 3). The resulting calcium and phosphate release was quantified photometrically. Slabs with and without a 30-min in situ pellicle served as controls. The modification of pellicle ultrastructure was evaluated by transmission electron microscopy (TEM). Results: Plant extracts modulated the erosion-protective properties of the native in situ pellicle in all test groups in a pH-dependent manner. The combination of R. nigrum leaves and Origanum enhanced the protective properties of the pellicle at all pH values; the administration of this preparation was comparable, yet superior, to the effect of the fluoridated mouth rinse. TEM images indicated that rinsing with R. nigrum leaves/Origanum yielded a distinctly thicker and more electron-dense pellicle. Conclusion: The combination of certain plant extracts offers a novel approach to the complementary prevention of dental erosion.

Newly developed functionally graded workpieces made of AISI 6150 (51CrV4), pose great challenges to the machining process due to the combination of different material properties (e.g., hardness) within one workpiece. A material model including more information than experimentally identified stress-strain curves for different temperatures is necessary to model the process more realistically. Therefore, the Johnson-Cook material model has been implemented for three-dimensional turning simulations within the Finite Element software DEFORM TM 3D. This paper outlines the adopted method to modify the parameters of the Johnson-Cook material model for two-dimensional and threedimensional FE-simulations in order to take material hardness into account. The primary objective was to improve passive and feed force computation by using this modeling approach, as it was observed that common material modeling showed large deviations of the feed force and passive force from the measured force components. The calculated feed force and passive force, as well as the cutting force, are validated experimentally. In conclusion it is shown that the application of the Johnson-Cook material model reveals more valid results for modeling the turning of workpieces with varying hardness values.

Blended learning is characterised as a combination of face-to-face teaching and e-learning in terms of knowledge transfer, students' learning activities and reduced presence at the teaching facility. The present cohort study investigated long-term effects of blended learning regarding cognitive outcomes as well as self-indicated estimates of immediate learning effects on the affective domain in the inter-professional field of occupational medicine. Physiotherapy students (bachelor degree) at FH Campus Wien -University of Applied Sciences completed the course Occupational Medicine/Prevention either in a traditional teaching-learning setting entirely taught face-to-face (control-group, n=94), or with a blended learning model (intervention-group, n=93). Long-term effects (1.5 year follow-up) on the cognitive learning outcomes were assessed according to four levels of Bloom's learning objectives. In addition, students estimated potential benefits resulting from blended learning based on four Krathwohl's learning objectives for the affective domain by means of a six-option Likert scale (n=282). Concerning cognitive outcomes, significant results favouring both groups were found with effect sizes from small to medium. The traditional teaching-learning setting resulted in significantly better results in the upmost aspired learning objective (analysis) at the long-term (p<0,01; r=-0,33). In contrast, the intervention group resulted in significantly better long-term results on learning objective levels 1 (knowledge) and 2 (understanding) (p=0,01; r=-0,20 and, p=0,02; r=-0,17, respectively). Hence, no general recommendation favouring either the classical setting or blending learning can be drawn regarding the cognitive domain. However, students' self-indications on the affective domain give preference to blended learning, particularly if inter-professional teamwork is a course objective.

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