Search

Aim: To compare the precision of centric relation (CR) assessment by various methods using digital technologies., Material and Methods: Determination of the CR was carried out in the clinic of prosthetic dentistry on patients with intact dentition using methods of bilateral manipulation, anterior jig, leaf gauge and device for intraoral recording of the gothic arch angle. Optical jaw impressions were obtained using the intraoral 3D scanner Trios (3Shape) and the CR registers were scanned using the laboratory scanner Prime (DOF). To evaluate the reproducibility of the CR, the computer program of 3D modeling Avantis (Russia) was used, which integrated the obtained optical impressions and digital copies of the CR registers., Results: None of the methods showed 100% accuracy in CR assessment. The most stable reproducibility of the position of the mandible in the CR relative to the first registration was determined by the method using an anterior jig (of our own design) and amounted to 0.119±0.012 mm, which is significantly less than using the methods of bilateral manipulation (0.225±0.028, p≤0.05) and a leaf gauge (0.207±0.02, p≤0.05). We observed a similar mean values of the reproduction accuracy when determining the CR by recording the Gothic arch angle (0,120±0,013, p≤0.05), which also has a significantly lower value (p≤0.05) compared to other methods for CR determining.

The aim of the study was to investigate accuracy of the most frequently used methods of obtaining centric relation in clinical practice. Finding of CR was carried out in clinic of prosthodontic dentistry on a 5 patients with intact dentition using four methods that are most often used, including: bimanual manipulation, leaf gauge, using an anterior deprogrammind device, the technique of determining CR with intraoral devices recording the gothic angle. To assess the accuracy of each technique there were performed 10 registrations of the central relation by one operator (200 CR registrations), with 30 minutes' intervals between the CA determination. Analysis of the contacts in CR were carried out using a photometric method of investigation. The graphic images were downloaded in Adobe Photoshop for calculation, metric data translated into digital values. The studies above showed that the accuracy of finding CR in all methods were not ideal. It can be noted that the smallest deviation of the position of the first contact in the CR was observed with use of the anterior deprogrammind device and with the intoral gothic angle recording device. The deviation along the VO axis was 0.039±0.002 mm and 0.084±0.004 mm respectively, along the MD axis 0.043±0.002 mm and 0.054±0.001 mm, respectively. The greatest error of recording the CR was shown by bimanual manipulation Dawson technique, the deviation along the axis of the VO and MD was 0.634±0.04 mm and 0.388±0.04 mm, respectively.

Further developments of antibacterial coatings based on photocatalytic nanomaterials could be a promising route towards potential environmentally friendly applications in households, public buildings and health care facilities. Hereby we describe a simple chemical approach to synthesize photocatalytic nanomaterial-embedded coatings using gypsum as a binder. Various types of TiO 2 nanofiber-based photocatalytic materials (nitrogen-doped and/or palladium nanoparticle decorated) and their composites with gypsum were characterized by means of scanning (SEM) and transmission (TEM) electron microscopy as well as electron and X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) techniques. These gypsum-based composites can be directly applied as commercially available paints on indoor walls. Herein we report that surfaces coated with photocatalytic composites exhibit excellent antimicrobial properties by killing both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) under blue light. In the case of MSSA cells, the palladium nanoparticle-decorated and nitrogen-doped TiO 2 composites demonstrated the highest antimicrobial activity. For the MRSA strain even pure gypsum samples were proven to be efficient in eradicating Gram-positive human pathogens. The cytotoxicity of freestanding TiO 2 nanofibers was revealed by analyzing the viability of HeLa cells using MTT and fluorescent cell assays.

We fabricated composite nanoparticles consisting of a plasmonic core (gold nanorods or gold-silver nanocages) and a hematoporphyrin-doped silica shell. The dual photodynamic and photothermal activities of such nanoparticles against Staphylococcus aureus 209 P were studied and compared with the activities of reference solutions (hematoporphyrin or silica-coated plasmonic nanoparticles). Bacteria were incubated with nanocomposites or with the reference solutions for 15 min, which was followed by CW light irradiation with a few exposures of 5 to 30 min. To stimulate the photodynamic and photothermal activities of the nanocomposites, we used LEDs (405 and 625 nm) and a NIR laser (808 nm), respectively. We observed enhanced inactivation of S. aureus 209 P by nanocomposites in comparison with the reference solutions. By using fluorescence microscopy and spectroscopy, we explain the enhanced antimicrobial effect of hematoporphyrin-doped nanocomposites by their selective accumulation in the vicinity of the bacteria., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The structure, composition and photocatalytic activity of TiO(2) nanoparticles annealed in various gas atmospheres (N(2), NH(3) and H(2)) were studied in this work. The effect of treatment on crystal structure, particle size, chemical composition and optical absorbance were assessed by means of x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy and diffuse optical reflectance/transmittance measurements, respectively. Photocatalytic properties of the materials were evaluated by three different methods: degradation of methyl orange in water, killing of Staphylococcus aureus bacteria and photogeneration of radicals in the presence of 3-carboxy-2,2,5,5-tetramethyl pyrrolidine-1-oxyl (PCA) marker molecules. The results indicate that the correlation between pretreatment and the photocatalytic performance depends on the photocatalytic processes and cannot be generalized.