Materials Science Forum Vol. 805

Abstract: The Nitinol is a term which represents the family of nickel and titanium alloys. With the discovery of the extraordinary biocompatibility of these alloys, their implementation has been emphasized in the medical devices and in general dentistry. The characteristics which make these alloys are of interest its superelasticity, shape memory effect and excellent biocompatibility, the latter two characteristics particularly interesting due to the fact that these materials confer the ability to self-expansion or contraction and not presenting rejection the organism. Thus, this study aims to evaluate three NiTi alloys compositions, being one rich in titanium, other poor and the last equiatomic, through tests of physical characterization and surface tension, after different heat treatments. After the results interpretation, it can be seen that the lower percentages by weight of nickel in their products from corrosion was the Nitinol rich in titanium subjected to heat treatment for 24 hours in the oven. Moreover, the same composition present the smallest angle in the test of surface tension.

Abstract: This work aims to conduct a study of development and characterization of a new endodontic biociment, the MTA/HAp. To this was used MTA Angelus ^® and a HAp synthesized in the laboratory in the proportions by weight 99% MTA/1% HAp (BIOC 1) and 95% MTA/5% HAp (BIOC 5), where the hydroxyapatite was added in order to introduce MTA to the characteristic of osteoconduction. The tests for the characterization of new cement were: X-ray diffraction, scanning electron microscopy and radiographic appearance. The results showed that the new developed biociments were obtained efficiently, since they showed the same crystalline phases of its starting materials (mineral trioxide aggregate and hydroxyapatite), with a morphology consisting of agglomerates of homogeneous distribution of irregular size and shape particles pre-sintered spherical and radiopacity feasible to be used in endodontics. Keywords: biomaterial, sealer, mineral trioxide aggregate, hydroxyapatite.

Abstract: The Glass Ionomers Cements (GICs) are materials widely used in dentistry, have advantages such as fluoride release and chemical adhesion to the dental substrate. They are recommended as a restorative material, luting agent in prosthetic dentistry and also in medicine. However, there is need for developing new bone cements as an alternative or replacement to the current polymethylmethacrylate cements, therefore, the objective of this research was to develop an experimental GIC and characterization regarding morphology, chemical composition and crystallinity. This composite was characterized by X-ray diffraction (XRD), Infrared Spectroscopy Fourier Transform (FTIR) and optical microscopy (OM). For comparative study, was used the GIC Vidrion R (SS White) in the control group. These cements are presented in semi-crystalline diffraction patterns, the FTIR spectra observed characteristic bands of these materials and microstructural study of the cements showed homogeneous distribution of filler in the polymer matrix, corroborating with the literature.

Abstract: Biocompatibility is the ability of a material appropriate trigger a biological response, when applied to the body, without causing a chronic inflammatory reaction, foreign body reaction or toxicity, is related to the interaction of the cell / biomaterial. A few materials, if any, are completely inert from the physiological point of view since, most of the components with a variety of potential toxic or irritating. In addition, chemical reactions during cure of the material may also produce undesirable effects. In order to increase knowledge about the characteristics and properties of materials and their interaction with the biological environment, this study aimed, through literature review, guide and inform didactically professionals and academics on the importance of biocompatibility of restorative materials more direct use in dental practice: silver amalgam, composite resins and glass ionomer cements. It was concluded that, among the restorative materials studied, the glass ionomer cement showed the best characteristics and properties that confirm its biocompatibility in dental practice.

Abstract: Chitosan has been the focus of an extensive research in recent years, especially due to its biodegradability, biocompatibility and the possibility to be processed in many form, shapes and sizes. Besides, chitosan can ben chemically modified and this modification through crosslinking can produce materials with a wide variety of properties. The aim of this present work was to produce and characterizing ionic crosslinked chitosan scaffolds. Chitosan scaffolds were prepared by the freeze drying technique and crosslinking was introduced by a chemical reaction with sulfuric acid solution. The non-crosslinked and crosslinked chitosan scaffolds were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). According to FTIR results, an effective reaction between the sulfate ions and chitosan scaffolds was achieved with visible changes in the spectra. This reaction also could be seen on EDS results with sulfur peaks presents in all the crosslinked samples. The SEM results showed that the crosslinking reaction doesn ́t modified the chitosan scaffolds tridimensional structure.

Abstract: The incorporation of calcium phosphate in a polymer matrix for composites production combines the flexibility of the polymers with the resistance, hardness and bioactivity of the inorganic phase. This study aimed to obtain rigid biocomposites using hydroxyapatite as mineral phase and chitosan as a polymer binder for the application as a biomaterial. To obtain the biocomposites, hydroxyapatite was added under constant stirring to a solution of chitosan in order to satisfy a 70:30 (HA/CS) ratio. XRD results showed no significant change in the profile of hydroxyapatite with the incorporation of chitosan. The analysis of scanning electron microscopy (SEM) of the biocomposite HA/CS, indicated that there was an excellent dispersion of HA particles in the polymeric matrix. Infrared Spectroscopy with Fourier Transform (FTIR) analysis proved an existing interaction between chitosan and hydroxyapatite. The biocompatibility of biocomposites HA/CS was confirmed by the MTT assay. It is considered that the present biocomposites are a promising biomaterial for trabecular bone grafting

Abstract: Sterilization is a procedure which promotes complete destruction or elimination of all forms of microorganisms. It is a fundamental stage in the processing of biomaterials, and functionality of any sterilization system must be determined by its effectiveness in exterminating microorganisms without harming or adversely affect the properties of medical devices. Some sterilization techniques can react with functional groups of the polymer leading to changes in the properties, affecting the biomaterial. This study aimed to develop chitosan membranes sterilize them by following methods: an autoclave, ethylene oxide, glutaraldehyde and ultraviolet radiation and characterized by FTIR, XRD and SEM. Based on the results of this study it can be concluded that the method of sterilization indicated for the membranes of chitosan is ethylene oxide because the other altered physicochemical properties thereof.

Abstract: Waste recycling has been stepped up around the world to enhance the quality of the recycled product and provide greater efficiency in the production system. The increasing use of polymers has led to increasingly multiple uses of these materials due to their high degradation time. The polyethylene used in plastic co-extruded with the use of ethylene vinyl alcohol (EVOH) has been a major advantage in prolonging the useful cycle of the final product. Thus the technique of co-extrusion has become very attractive in the packaging industry because it enables the design of multi-layer structures. Thus, this work aims at assessing the conditions of use of recycled material in packaging for co-extruded with application properties of a biomaterial. The packages used in this study are composed percentages of high density polyethylene (HDPE) recycled, virgin polyethylene and gas barrier (EVOH), where they were subjected to 50 ° C in an oven stabilized at room temperature as well as the approximately 23 ° C, conditioned in the laboratory. The packages were characterized by spectroscopy techniques in the Region of Fourier Transform Infrared (FTIR), Surface Tension and optical microscopy (OM). With the technique, FTIR was possible to verify the presence of characteristic bands of polyethylene. As for the measures surface tension was possible to observe an increase in the wettability of containers subjected to high temperature. It was also possible to see through the optical microscope the difference of packaging is compounded by the EVOH. The results presented so far do not suggest an indication of the occurrence of rust on packaging, allowing an indication of use.

Abstract: The arthroplasty is a surgical procedure which is characterized by replacing the defective joint surfaces of biomaterials intended to restore the function of these joints. As soon because the relevance of the topic, this paper aims at studying the unconformities two hip prostheses, titanium and other stainless steel front to standardizations. The implants studied were characterized by techniques: X-ray fluorescence, microanalysis Dispersion Energy X-ray diffraction, scanning electron microscopy and optical microscopy, and tests were carried out physic-mechanical traction and hardness. The unconformities present are analyzed and discussed.