Papers by Author: Joanna Mystkowska

Abstract: The present paper describes the results of the physicochemical and rheological characterisation of the selected self-made solutions of synthetic saliva. The substitutes of the used saliva were prepared on the basis of gums (xanthan, guar, arabic and carob bean) dissolved in saline buffer. Additionally, one of preparations were composed of xanthan gum and sodium dodecyl sulphate (SDS). The analysis of the viscosity, pH, surface tension and conductivity of the tested solutions was performed. The tests were carried out following one, three and seven days. The obtained results of the conducted studies showed differences between the tested preparations in the scope of the above evaluated quantities. The preparations based on the tested gums have similar properties in terms of pH, surface tension and conductivity. Only the substitute with the addition of xanthan gum and SDS exhibited different characteristics: the highest value of pH and the lowest values of conductivity and surface tension. In the case of viscosity, some preparations exhibited Newtonian rheological characteristics while others exhibited non-Newtonian characteristics.

Abstract: The present paper describes the results of tests on the influence of selected self-made solutions of synthetic saliva on tribological characteristics of implant materials on the example of the Co-Cr-Mo alloy. The used saliva substitutes were prepared on the basis of gums (xanthan, guar, arabic and carob bean) dissolved in saline buffer. Analysis of the values of the coefficient of friction and the wear of the tested dental alloy in tested solutions was performed. Different values of the coefficient of friction were observed for friction pairs tested in individual solutions. Its lowest values were achieved during tests using xanthan gum with SDS (sodium dodecyl sulfate) addition, and the highest values were achieved for xanthan gum. As regards wear analysis, its lowest value was registered during lubrication with natural saliva. Among saliva substitutes, the lowest value of mass wear of dental alloy was observed in solution of xanthan gum, and the highest value was registered for carob bean gum. After friction tests, elements of the friction pair were subjected to microscope analysis using the Olympus BX61 optical microscope.

Abstract: The aim of the work was the assessment of adsorption capabilities of selected animal mucins. In this work two animal mucins (mucin porcine stomach, type II and III), which were dissolved in phosphate buffered saline were evaluated. The tested materials, where the adsorption of glycoproteins takes place, were surfaces of two implantation materials: titanium alloy (Ti-6Al-4V) and 316L steel. The standardized samples of materials were immersed in solution of mucin II and solution of mucin III aseptically prepared) for: 10 minutes, 120 minutes, 1 day and 5 days. The UV spectrophotometry method was used for analysis of the mucin concentrations as a simple and effective technique. The obtained results clearly indicate that the tested surfaces are covered by the mucins used for experiments. However, quantitative analyses of adsorbed mucins did not show significant differences, both between tested materials, and mucins.

Abstract: This work presents application of the methods of combined analytical techniques: high performance capillary chromatography and mass spectrometry with a nanoelectrospray ion source (nanoESI) for biochemical analysis of biological films. The layers of biofilm (identification of surface proteins) adsorbed on surfaces of metallic plate fixation and metallic screws surfaces used during treatment of the mandibular fracture were investigated. The obtained results make it possible to determine the protein composition of films found on the plates and screws used for fixation of the mandible. Second part of the work involves microscopic observations of specially prepared parts of tissues contacting directly with time-part implant. We observed changes in the osseous tissues and relocations of the metal ions from the fixations using a Hitachi S-3000N scanning microscope, equipped with an NSS type (Noran System Six) X-ray spectrometer and a freezing table for biological sections. Obtained results indicate the penetration of metal ions from the time-part implant surface into the osseous tissue.

Abstract: In the paper a study of surface composition and fluid sorption by several titanium alloys immersed in a simulated body fluid is presented. Four materials were investigated: pure titanium, two beta titanium alloys and stainless steel 316L. All the materials were prepared using cold pressing and sintering. Sample plates were submitted to nucleation and growth of calcium phosphates precipitated from SBF solution containing calcium, phosphate and other ions. Analysis with scanning electron microscope has revealed some calcium phosphates aggregates on surfaces of all the alloys. The results indicate that the nucleation and growth of phosphates depend on the alloy composition and the process is more intensive in the case of titanium alloys with niobium additions. On the other hand, this material is characterized by the smallest SBF sorption. Chemical analysis using near infrared spectroscopy indicated a presence of some organic groups on the material surface.

Abstract: This work presents results of research on compressive strength, microhardness, polymerization shrinkage and water sorption of some specially developed composite materials for dental fillings. The investigated powder fillers were divided into two groups: fluorine-based fillers, such as fluoridated glass, strontium fluoride, ytterbium fluoride and additives of improved mechanical characteristics such as nanosilica and polyethylene. The influence of fluoride ion source on the properties of the composite materials was evaluated. Tests were performed just after the material polymerization and, additionally, after seven, thirty and sixty days. Some small differences between composites were observed.

Abstract: Ceramic – polymer composites based on acrylic (bis–GMA) and urethane – methacrylate (UM) resins with a 60 % total volume fraction of filler consisting of micro particles of glass and nano-particles of silica were fabricated. The nano-silica contents were: 0, 10, 20 vol. %. The composite samples were subjected to wear tests using an occlusion simulator tester which applies reciprocating movement and cyclic loading on the test material. This method of testing provides some similarity to the masticatory pattern occurring in the mouth during eating. The enamel of a human tooth was used as a counter-sample. The coefficient of friction was determined and the wear resistance of the composite samples containing the various nano-silica contents was established. In addition, the relative influence of the composite composition on the rate of wear of the human tooth enamel was estimated. The results of the study indicate that the addition of nano-silica significantly improves the wear resistance of the ceramic – polymer composites and reduces the wear of enamel. It was found that the addition of nano-silica has no influence on the coefficient of friction. It was also established that composites based on UM resin show better wear resistance than those based on a mixture of bis-GMA and TEGDMA resin.

Abstract: This work presents results of research of fluoride release, microhardness and surface roughness and wear of the Tetric EvoCeram material. Wear tests were carried out by means of special tribotester for tooth analysis and by pin-on-disc tribometer. The wear of composite material and counterface (human enamel) were measured. Finally, investigations showed that fluoride ions from commerce material were slightly released. However, the amount of fluoride ions release was depended on pH and temperature of agent solution. Fluorine emission from composite material changed its surface roughness and microhardness. The using method of wear process influenced on friction coefficient value. During friction process the wear layer on composite surface was formed.

Abstract: In the paper own prepared materials with addition fluorine sources were evaluated. The aim of the study was to assess the quality and quantity of fluoride source on fluoride ions release from composite materials. Antibacterial activity of analyzed materials in relation to four bacteria was investigated. Fluoride ions release was measured by direct potentiometry method with fluoride ion selective electrode. The measurements were carried out after 1, 4, 7, 14, 30, 60 days of storage in buffer at pH 6.8. The antibacterial activity of the materials was evaluated against standard bacterial strains using the agar diffusion test. Tests show that the highest level of fluoride ions emission was observed for composite with fluoridated glass (material A) on the seventh day of the study. Similar fluoride ions amount was released from material consisted of fluoridated glass and ytterbium fluoride (material C), but not until on the thirtieth day of the study. After 24 hours of composite bonding there was inhibition of bacterial growth by composite C, whereas composite A did not show similar activity. On the eighth day after polymerization, both materials were significantly more active towards two bacteria.

Abstract: The aim of this study was to determine the influence of powder fillers on the tribological properties of composite materials used for dental fillings. The investigated composites contain a fluoridated filler (based on Ba-Sr-Al-P-Na-silicate glass fillers) as a fluoride source as well as different powder fillers (friction modifiers) e.g. silicon nitride (Si3N4), boron nitride (BN), polyethylene (PE), polytetrafluoroethylene (PTFE). Composite disks were photo-cured and tested for wear against harder stainless-steel counterface. Wear tests were carried out by means of special tribotester in the presence of phosphate buffer as a lubricant. Influence of the load and filler contents on the friction coefficients and wear were estimated. The interaction between the filler particles and organic matrix and its influence on the tribological behavior of prepared specimens were observed. Organic powder fillers (PE, PTFE) reduced the friction coefficient and the wear of tested composite materials for dental fillings. Inorganic friction modifiers (Si3N4, BN) did not exhibit this effect.