Katarzyna Banaszek

Adhesion of E. coli Bacteria Cells to Prosthodontic Alloys Surfaces Modified by TiO2 Sol-Gel Coatings

The evaluation of the degree of bacteria E. coli adhesion to modified surfaces of the chosen prosthodontic alloys was presented. The study was carried out on Co-Cr (Wironit), Ni-Cr (Fantocer), and Fe-Cr-Ni (Magnum AN) alloys. Bare substrate as a control and titanium dioxide coated samples were used. The samples were placed for 24 hours in bacterial culture medium. After incubation period, a number of bacterial cells were evaluated by scanning electron microscope. The study revealed that modification of the alloy surfaces by titanium dioxide coating significantly decreases the amount of bacteria adhering to the surfaces and that additionally bare metal alloy substrates have a different degree of susceptibility to bacterial adhesion.

The Sensitivity of Endodontic Enterococcus spp. Strains to Geranium Essential Oil

Enterococci are able to survive endodontic procedures and contribute to the failure of endodontic therapy. Thus, it is essential to identify novel ways of eradicating them from infected root canals. One such approach may be the use of antimicrobials such as plant essential oils. Enterococcal strains were isolated from endodontically treated teeth by standard microbiological methods. Susceptibility to antibiotics was evaluated by the disc-diffusion method. The minimal inhibitory concentration (MIC) of geranium essential oil was investigated by microdilution in 96-well microplates in Mueller Hinton Broth II. Biofilm eradication concentrations were checked in dentin tests. Geranium essential oil inhibited enterococcal strains at concentrations ranging from 1.8–4.5 mg/mL. No correlation was shown between resistance to antibiotics and the MICs of the test antimicrobials. The MICs of the test oil were lower than those found to show cytotoxic effects on the HMEC-1 cell line. Geranium essential oil eradicated enterococcal biofilm at concentrations of 150 mg/mL. Geranium essential oil inhibits the growth of endodontic enterococcal species at lower concentrations than those required to reach IC50 against the HMEC-1 cell line, and is effective against bacteria protected in biofilm at higher concentrations. In addition, bacteria do not develop resistance to essential oils. Hence, geranium essential oil represents a possible alternative to other antimicrobials during endodontic procedures.

Complex XRD and XRF Characterization of TiN-TiCN-TiC Surface Coatings for Medical Applications

Article presents results of measurements of vital parameters of PVD coatings of potential application in medicine (joint replacements or medical tools). The phase identification, level of residual stresses and texture were determined for various coatings by X-ray diffraction method. Chemical composition of coatings was verified by means of XRF. A set of measurements reveled the existence of advantageous compressive stresses in coatings, the texture determination showed undesirable fiber texture in TiN coating and advantageous uniformity of TiCN ones. XRF analysis pointed out the necessity of careful preparation of samples during PVD process during which phenomena of inhomogeneity in chemical can be present as it is presented in the paper.

Possibilities of applying Ti (C, N) coatings on prosthetic elements - research with the use of human endothelial cells.

PURPOSE The aim of our study was to examine the effect of prosthetic alloys with Ti (C, N) coatings on viability and pro life ration of human cells employing an MTT assay with the use of human microvascular endothelial cells derived from the skin - HMEC-1 (Human Microvascular Endothelial Cells-1). METHODS Cylindrical shape samples made of Ni-Cralloy were divided into S1-S5 groups and coated with Ti (C, N) layers with different content of C and N. S0 group - control group without layer. The alloys (S0-S5) were stored in an experimental medium (MCDB131 with antibiotics) for 30 days and then HMEC-1 cells were incubated in the alloy extract for 24 and 96 hours. Next, cell viability was determined using MTT method. RESULTS In the case of samples incubated for both 24 and 96 hours there are statistically significant differences (with p-value <0.05) between the uncoated samples (S0 group) and all the other Ti (C, N) coated samples. Higher absorbance values were observed in all coated groups than in the control S0 group, where cell growth was statistically significantly lower. CONCLUSIONS During incubation of endothelial cells with coated samples the number of cells was significantly bigger than the number with uncoated alloys. The best viability of cells was obtained from the S = 3 (with 51.94% at. Ti, 28.22% at. C and 19.84% at. N) group of samples. Ti (C, N) coatings may be applied as protective components on prosthetic elements made of base metal alloys.