Bohdan Bączkowski

Numerical analysis of the implant --- abutment system

An important characteristic of dental implants is the configuration of the coupling between implant and abutment. The aim of numerical analysis was calculation of displacements and stresses in an implant system in a function of the applied loading - imitating phenomena in the mouth during mastication. The commonly used internal connection implant complex was modelled in accordance with the geometric designs and scanning electron microscopy observation. Because an excessive stress concentration at the implant-abutment interface is suggested to be critical for the long-term success of implant therapy, the analyses of this aspect can make it possible to evaluate the type of failure of the system and identify its weakest elements. Geometric models of implant systems, were discretized by means of tetrahedron element using the software programs Catia V5.

Electrochemical Behavior of Materials Used in Dental Implantological Systems

Favorable physical and chemical properties of titanium led to its use in the medical and dental specialties such as: orthodontics, prosthodontics, dental implantology and dental surgery. Estimating the biocompatibility of the material, determine the risks and benefits with its use is a complex process. In dental implantology, the attachment of a dissimilar metal abutment (Ti6Al4V) to an implant (commercially pure Ti) forms a galvanic couple in the mouth; they are placed in physical contact in an electrically conductive mediums – body fluids.

Preparation and characterization of ZnO-PMMA resin nanocomposites for denture bases

PURPOSE The aim of the paper was to investigate the antifungal activity of zinc oxide nanoparticles (ZnONPs) against Candida albicans. Some attempts have been made to find out the best way to introduce ZnONPs into polymethyl methacrylate (PMMA) resin material and to determine some parameters of a newly formed composite. MATERIAL AND METHODS Zinc oxide nanoparticles were manufactured and their basic physical parameters were determined (average particle size, density, specific surface area). Minimal inhibitory concentration (MIC) of ZnONPs was determined for the Candida albicans standard strain. The average size of ZnO conglomerates in the monomer solution of PMMA resin was measured using a dynamic light scattering instrument. PMMA resin samples with incorporated ZnONPs were produced. The morphology of nanopowder and the newly formed composite was examined under a scanning electron microscope (SEM). In addition, the roughness parameter of PMMA resin material was investigated before and after ZnONPs modification. RESULTS Nanopowder with the average particle size of 30 nm, density of 5.24 g/cm3 and surface area of 39 m2/g was obtained. MIC was determined at the level of 0.75 mg/mL. The average size of ZnO conglomerates in the monomer solution of acrylic resin dropped by 11 times after ultrasound activation. SEM examination of a newly formed composite showed a successful introduction of ZnONPs confirmed by the energy dispersive X-ray spectroscopy (EDS) analysis. There were no statistically significant differences in the biomaterial roughness before and after the modification of ZnONPs. CONCLUSION Zinc oxide nanoparticles were successfully incorporated into acrylic resin used for the production of denture bases. The presence of nanoparticles with sizes below 100 nm was confirmed. Nevertheless a newly created composite needs to be further investigated to improve its homogeneity, and to check its microbiological properties, strength and biocompatibility prior to its possible clinical use.

Electrochemical Properties of Ni-Cr and Co-Cr Alloys Used in Prosthodontics

The aim of the work was evaluation of electrochemical properties of Co-based alloys (Remanium GM 800+ and Biosil F) and Ni-based alloys (Heraenium NA and Remanium G-Soft) commonly used on frameworks for porcelain faced cast partial dentures. First stage of the work was evaluation of surface roughness by means of direct linear contact measurement (SURTRONIC 3+ profiler, Taylor/Hobson) of samples after casting and surface treatment. Electrochemical properties of surface were assessed by means of potentiodynamic and impedance methods. In potentiodynamic tests, in order to evaluate pitting corrosion resistance of the analyzed alloys, anodic polarization curves were recorded. The VoltaLab® PGP 201 system was applied in corrosion tests. Moreover, in order to evaluate structure and properties of the surface layer the electrochemical impedance spectroscopy (EIS) was applied. Selection of this method enabled to determine the impedance of the material – surface layer – solution interface with the use of approximation of impedance data by means of equivalent electric circuit model. The EIS tests were carried out with the use of the AutoLab PGSTAT 302N system equipped with the FRA2 Faraday impedance module. Electrochemical tests were carried out in artificial saliva at the temperature of 37°C and pH = 7,0±0,1.

Laboratory Evaluation of the Fit of Anti-rotational Elements at the Hybrid Implant Abutments Used in Prosthetic Dentistry

Hybrid implant abutments join the features of standard metal-ceramic implant abutments and custom made pure ceramic ones. They are made of zirconium oxide in CAD/CAM technology and are combined with a base made of titanium, supplied by the manufacturer of the implants. The aim of the study was to evaluate the marginal seal at the border of the implant and hybrid abutment, as well as the degree of fit of these elements. Both marginal seal and the degree of matching between the Replace Select 4.3 (Nobel Biocare, Sweden) implant and the hybrid abutment fall within the limits described in the literature.

Periimplantitis as the Cause of Separation the Prosthetic Bridge Based on Implant

The paper discusses the basic problems of the possible complications after implant-prosthetic treatment, with particular emphasis on periimplantitis. Presented are the results of materials science expertise for prosthetic bridge based on the implant, lost by sixty year old female patient as a result of perigraft tissue inflammation. The results allowed to assess whether the separation of the prosthetic system – in addition to biological factors – was influenced by mechanical factors, such as damage to restoration structures.