No abstract

No abstract

Ultralight magnesium alloys are wide used in the medical field, especially for biodegradable implants. Although they are wide used, magnesium has low corrosion resistance. To improve this resistance, different types of alloys based on magnesium and Ca, Mn, Zr and Y can be developed. The main goal of the present paper is to investigate the properties of some master alloy based on Mg-X system (Ca ,Mn, Zr, Y) used in the development of biodegradable based alloys of Mg. The surface morphology was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and optical microscopy. After the XRD analysis, there was observed that some specific compounds were formed of Mg2Ca, Mg0.97Mn0.025, MgZr, Mg2Y, Mg24Y5 having the main Mg phase formed in the hexagonal structure. There were also evaluated the master alloys micro-hardness values in the range of 58.41 HV (Pure Mg), 67.97 HV (Mg-3Mn), 85.12 HV (Mg-25Zr), 131.8 HV (Mg-15Ca) and 291.45 HV (Mg-30Y). The corrosion resistance was developed using electrochemical testing in specific medium and there is shown that the corrosion rate increased significantly for the master alloys investigated, rather than pure magnesium. As a final conclusion structural properties of these alloys recommend them for usage as medical implants.

Ceramic materials are used for the fabrication of dental restorations respectively esthetic dentistry. The main ceramic materials are glass ceramics, spinel, alumina and zirconia. Zirconia was introduced into dentistry domain in the 1990s used like frameworks, implants, dowels, abutments and orthodontic brackets. Recently, zirconia materials are getting much attention for dental implants because of its toothlike color, mechanical properties, good corrosion and biocompatibility. This article presents an review of zirconia dental implants osseointegration and mechanical strength compared with other dental implants. Clinical studies published indicate that zirconia dental implants have the potential to become alternative of titanium dental implants used in medical applications.

The present article is a preliminary study focused on the influence of zirconia surface on deposition of hydroxyapatite. The surface characteristics are very important for deposition of various materials. Most of the studies on zirconia are focused on dopped ZrO2 composites or on surface enhancement of these kind of materials. One of the most important property is the osseointegration which can be enhanced with various kind of treatments or deposition. Our preliminary study involved the mechanical grinding and respectively the chemical attack of the surface before the deposition. The results highlights that in order to obtained a better layer of hydroxyapatite the surface of the zirconia samples need to be prepared by chemical attack.