13,022 research outputs found

    A Technique for Duplicating a Fixed Complete Denture

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    The fixed implant prosthesis often requires repair due to fracture and/or wear of acrylic resin teeth. Repair of such a prosthesis, although simple, requires retaining the prosthesis to be revised in the laboratory. In order to reveneer the implant prosthesis, a provisional restoration should be fabricated for the patient that provides similar function and esthetics. This article presents a technique for duplicating the existing fixed implant-supported prosthesis prior to repair/reveneer, thus providing a smooth transition from the provisional to the definitive prosthesis

    Repairing an Implant Titanium Milled Framework using Laser Welding Technology: A Clinical Report

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    The application of laser welding technology allows titanium to be welded predictably and precisely to achieve accurate fit of a milled framework. Laser energy results in localized heat production, thereby reducing thermal expansion. Unlike soldering, laser energy can be directed to a small area, making it possible to laser weld close to acrylic resin or ceramic. This article describes the use of laser welding to repair an implant titanium milled fixed denture. A quick, cost-effective, accurate repair was accomplished, and the repaired framework possessed adequate strength and the same precise fit as the original framework

    Gingival Abscess Removal Using a Soft-Tissue Laser

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    Gingival abscess, also known as parulis, is defined as a localized, acute inflammatory lesion that may arise from a number of sources, including microbial plaque infection, trauma, and foreign body impaction. It often presents as a smooth, fluctuant, red-color swelling and can occasionally be painful. It is generally limited to marginal and interdental gingiva. Based on its location it has been classified as a type of periodontal abscess which does not involve any attachment loss. The treatment comprises of removal of the cause and, in acute situations, excision of the abscess. A typical gingival abscess is easy to diagnose; however, as suggested by the lack of literature, it is rarely seen in clinical situations. This article presents a clinical case of a gingival abscess located adjacent to recently-placed implants, and discusses its etiology, histopathology, and treatment with an 810-nm soft-tissue diode laser

    Chemical composition of the stellar cluster Gaia1: No surprise behind Sirius

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    Indexación: Web of Science; Scopus.We observed six He-clump stars of the intermediate-Age stellar cluster Gaia1 with the MIKE/Magellan spectrograph. A possible extra-galactic origin of this cluster, recently discovered thanks to the first data release of the ESA Gaia mission, has been suggested, based on its orbital parameters. Abundances for Fe, α, proton-And neutron-capture elements have been obtained. We find no evidence of intrinsic abundance spreads. The iron abundance is solar ([FeI/H] = + 0.00 ± 0.01; σ = 0.03 dex). All the other abundance ratios are generally solar-scaled, similar to the Galactic thin disk and open cluster stars of similar metallicity. The chemical composition of Gaia1 does not support an extra-galactic origin for this stellar cluster, which can be considered as a standard Galactic open cluster.https://www.aanda.org/articles/aa/abs/2017/07/aa31009-17/aa31009-17.htm

    Altering Occlusal Vertical Dimension Provisionally with Base Metal Onlays: A Clinical Report

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    This article presents a method for altering occlusal vertical dimension (OVD) to restore dentitions with limited restorative space due to loss of tooth structure. A provisional increase in OVD is achieved using predominately base metal onlays, which offer advantages over conventional techniques. The onlays are resistant to wear, may be bonded well to nonrestored and restored tooth surfaces with resin cements, and provide a fairly reversible method of increasing OVD. A patient situation is presented which demonstrates the use of provisional base metal onlays in complete mouth rehabilitation

    Discrete port-controlled Hamiltonian dynamics and average passivation

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    The paper discusses the modeling and control of port-controlled Hamiltonian dynamics in a pure discrete-time domain. The main result stands in a novel differential-difference representation of discrete port-controlled Hamiltonian systems using the discrete gradient. In these terms, a passive output map is exhibited as well as a passivity based damping controller underlying the natural involvement of discrete-time average passivity

    Coming out in the workplace: a comparative study between Italy and England

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    Introduction: The study aims to analyze the main characteristics and differences relating to the lived experiences of coming out in the workplace in two very different territorial contexts (Italy and England), looking at universities as a case study. Method: 30 sexual and gender minority university teachers (15 from Italy and 15 from England), ranging from 29 to 56 years of age (M = 41.66; SD = 10.13), were recruited in 2019 to participate in a qualitative research study. Data were collected through semi-structured interviews and analyzed in line with the assumptions of the six-step thematic analysis approach. Result: The propensity to come out in the workplace is mainly affected by legislative safeguards. However, policies and the regulatory framework alone are not enough. Results suggested that the cultural context and the working climate have an equally significant impact. Conclusion: The stigma toward LGBT + people cannot be eradicated overnight and changing cultural beliefs is a slow process that requires imaginative and creative methods to get students and the university community to interact with LGBT + people. Practical implications: Stimulating a bottom-up change within individual institutions can represent a possible strategy to activate a process of change and social inclusion toward the LGBT + community with an echo on the wider environmental and cultural context

    Long-term radial-velocity variations of the Sun as a star: The HARPS view

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    Stellar radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. We investigate the impact of the solar activity on the radial velocity of the Sun using the HARPS spectrograph to obtain measurements that can be directly compared with those acquired in the extrasolar planet search programs. We use the Moon, the Galilean satellites, and several asteroids as reflectors to measure the radial velocity of the Sun as a star and correlate it with disc-integrated chromospheric and magnetic indexes of solar activity that are similar to stellar activity indexes. We discuss in detail the systematic effects that affect our measurements and the methods to account for them. We find that the radial velocity of the Sun as a star is positively correlated with the level of its chromospheric activity at about 95 percent significance level. The amplitude of the long-term variation measured in the 2006-2014 period is 4.98 \pm 1.44 m/s, in good agreement with model predictions. The standard deviation of the residuals obtained by subtracting a linear best fit is 2.82 m/s and is due to the rotation of the reflecting bodies and the intrinsic variability of the Sun on timescales shorter than the activity cycle. A correlation with a lower significance is detected between the radial velocity and the mean absolute value of the line-of-sight photospheric magnetic field flux density. Our results confirm similar correlations found in other late-type main-sequence stars and provide support to the predictions of radial velocity variations induced by stellar activity based on current models.Comment: 11 pages, 7 figures, 2 tables, 1 Appendix; accepted by Astronomy and Astrophysic

    The cosmological Lithium problem outside the Galaxy: the Sagittarius globular cluster M54

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    The cosmological Li problem is the observed discrepancy between Li abundance, A(Li), measured in Galactic dwarf, old and metal-poor stars (traditionally assumed to be equal to the initial value A(Li)_0), and that predicted by standard Big Bang Nucleosynthesis calculations (A(Li)_{BBN}). Here we attack the Li problem by considering an alternative diagnostic, namely the surface Li abundance of red giant branch stars that in a colour magnitude diagram populate the region between the completion of the first dredge-up and the red giant branch bump. We obtained high-resolution spectra with the FLAMES facility at the Very Large Telescope for a sample of red giants in the globular cluster M54, belonging to the Sagittarius dwarf galaxy. We obtain A(Li)=+0.93+-0.11 dex, translating -- after taking into account the dilution due to the dredge up-- to initial abundances (A(Li)_0) in the range 2.35--2.29 dex, depending on whether or not atomic diffusion is considered. This is the first measurement of Li in the Sagittarius galaxy and the more distant estimate of A(Li)_0 in old stars obtained so far. The A(Li)_0 estimated in M54 is lower by ~0.35 dex than A(Li)_{BBN}, hence incompatible at a level of ~3sigma. Our result shows that this discrepancy is a universal problem concerning both the Milky Way and extra-galactic systems. Either modifications of BBN calculations, or a combination of atomic diffusion plus a suitably tuned additional mixing during the main sequence, need to be invoked to solve the discrepancy.Comment: Accepted by MNRAS, 10 pages, 5 figures, 1 tabl

    Strength Properties of Preceramic Brazed Joints of a Gold-Palladium Alloy with a Microwave-assisted Oven and Gas/Oxygen Torch Technique

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    Statement of problem The effect of microwave brazing on the strength properties of dental casting alloys is not yet known. Purpose The purpose of this study was to compare the strength properties of preceramic brazed joints obtained by using a microwave oven and a conventional torch flame for a high noble alloy (Au-Pd). Material and methods A total of 18 tensile bars made of an Au-Pd ceramic alloy were fabricated. Six specimens were cut and joined with a high-fusing preceramic solder in a specially designed microwave oven, and 6 specimens were joined with a conventional natural gas/oxygen torch. The remaining 6 uncut specimens were tested as a control. All the specimens were subjected to testing with a universal testing machine. A 1-way ANOVA was performed for each strength property tested. Results The tensile strength of the uncut group was the highest (745 ±19 MPa), followed by the microwave group (420 ±68 MPa) and the conventional torch group (348 ±103 MPa) (P Conclusions The microwave heating preceramic solder method demonstrated the excellent tensile strength of an Au-Pd alloy and may be an alternative way of joining alloys when a torch flame is contraindicated
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