This paper presents the effect of the sandblasting and sintering processes on the surface properties of some commercial yttria stabilized zirconia (Y-TZP) for monolithic dental restorations in dentistry. The surface properties of dental zirconia can be improved further through various surface treatment methods, like surface abrasion, roughening, chemical treatment, tribochemical coating, or selective infiltration etching. But all these treatments are made on the sintered samples, not on the pre-sintered discs as are delivered by the dental suppliers. The hypothesis of this paper was that the mechanical effect on the surface of pre-sintered disc of Y-TZP assured by airborne-particle abrasion with alumina will be maintained after the sintering process. Additionally, we will follow the presence of alumina particles on the Y-TZP surface after airborne-particle abrasion process. Surface modifications of the experimental samples was performed by sandblasting for 15 s with Al2O3 particles (average particle size 83 mm) at pressure of 2 bars, using a SAB-Caloris equipment. Morphological and surface changes in the sandblasted, respectively sandblasted and sintered samples of Y-TZP are examined by using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. It is found that the surface modifications made on the pre-sintered Y-TZP disc remain after sintering process, which not affects these mechanical modifications of the surface. Also, it was detected the presence of alumina particles on the Y-TZP samples after airborne-particle abrasion process and for this reason we recommend the use of zirconia particle for airborne-abrasion process.

In case of an orthopedic implant, it would be ideal that resorption to occur by biodegradation and bone remodeling. The main advantage of using resorbable orthopedic implants is eliminating the need for a new surgical procedure. The use of pure magnesium for orthopedic implants shows some drawbacks, which need to be considered and evaluated by in vitro and in vivo assays. One of the main problems encountered when pure Mg is used as biodegradable implant is represented by a high corrosion rate, faster than the rate of bone formation. The aim of this study is testing and evaluation of Mg-1Ca alloy from biocompatibility in vivo point of view. The purpose of in vivo test was to demonstrate good biocompatibility and lack of local and systemic toxicity of implants made by Mg-1Ca alloy. The study was conducted by implanting Mg-1Ca alloy parallelepiped shaped implants in the tibia of rabbits. In our tests related to Mg-1Ca alloy in vivo evaluation, there were no pathological increases in blood levels of Mg and Ca, or other elements, showing that it has no adversely affect to their metabolism. Also it shows a good bone integration, newly formed bone being adherent to the implant surface, with no tissue interposed between it and the bone. In conclusion, magnesium alloy Mg-1Ca represents a promising solution in orthopedic surgery, proving to be safe, with a high degree of biocompatibility and without toxic effects during in vivo testing.

Trauma orthopaedic surgery was the first domain to use degradable metallic implants made of magnesium alloys since the early 20th century. Unfortunately, the major limitation that consists of rapid degradation and subsequent implant failure, which occur in physiological environments with a pH between 7.4 and 7.6, prevents its widespread application. The biggest challenge in corrosion assay is the choice of the testing medium in order to reproduce more closely in vivo conditions. The current study was focused on two Mg-Zn-Ag alloys (Mg7Zn1Ag and Mg6Zn3Ag) and the Mg1Ca alloy. Dulbecco’s Modified Eagle Medium (DMEM) and Kokubo’s simulated body fluid solution (SBF) were selected as testing mediums and we follow the corrosion evaluation by the corrosion rate and mass loss. Also, the corrosion behaviour was interpreted in correlation with the microstructural features and alloying elements of the experimental magnesium-based alloys revealed by optical microscopy (OM), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDX). The experimental results highlight the more corrosive nature of the SBF environment and that a higher percentage of silver (2.5 wt.%) exhibited a better corrosion resistance. We consider that the magnesium alloy Mg6Zn3Ag showed valuable biodegradation characteristics to be considered as raw materials for manufacturing small trauma implants.

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The paper is focused on developing a client-server application that can be used in the secure communication of video information over the IP. The main interest in developing the application is as a multidisciplinary project that can help students to develop their practical skills. The interest for such an approach in learning appears in the context of the Bologna process where multidisciplinarity seems to be the preferred learning approach at the bachelor level, while interdisciplinarity fits mostly in the higher education levels. The multidisciplinary character of the project raises from the fact that it involves knowledge from fields such as data communications, information security, image processing, computer programming, mathematics etc. Thus, implementing an application in .NET Framework and using communication protocols and cryptographic primitives to assure some security objectives is a valid response to multidisciplinary learning in engineering.