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We present the results of comparative enzyme-linked immunosorbent assay of matrix metalloproteinases MMP-2, MMP-8, MMP-9; IL-1β and IL-6; tissue inhibitors of MMP (TIMP-1, TIMP-2), and TNF-α. The object of study was oral fluid of practically healthy subjects with intact periodontium and patients with chronic generalized periodontitis with various structural materials of dental restorations. It was found that MMP-9 in oral fluid could be considered as a marker of chronic generalized periodontitis irrespective of the presence or absence of metal dental restorations. The level of MMP-8 surpassed the normal only in oral fluid of patients with chronic generalized periodontitis with metal restorations. The correlations between the studied parameters in patients attest to relatively similar regulation of MMP, IL and TIMP secretion in oral fluid in practically healthy subjects with intact periodontium. In patients with inflammatory destructive periodontal diseases with and without metal dental restorations, the correlation coefficients indicate initiation of biochemical cascade accompanied by activation of cytokine production in response to etiological factors. Patients with periodontitis and metal orthodontic structures showed more pronounced reaction. Orthodontic structures made from chromium-cobalt, or chromium-nickel alloys in the oral cavity of these patients increased the levels of MMP-2, IL-1β and IL-6 in oral fluid.

This paper presents a study of Al2O3–ZrO2 (ZTA) nanocomposites with different contents of reduced graphene oxide (rGO). The influence of the rGO content on the physico-mechanical properties of the oxide composite was revealed. Graphene oxide was obtained using a modified Hummers method. Well-dispersed ZTA-GO nanopowders were produced using the colloidal processing method. Using spark plasma sintering technology (SPS), theoretically dense composites were obtained, which also reduced GO during SPS. The microstructure, phase composition, and physico-mechanical properties of the sintered composites were studied. The sintered ZTA composite with an in situ reduced graphene content of 0.28 wt.% after the characterization showed improved mechanical properties: bending strength was 876 ± 43 MPa, fracture toughness—6.8 ± 0.3 MPa·m1/2 and hardness—17.6 ± 0.3 GPa. Microstructure studies showed a uniform zirconia distribution in the ZTA ceramics. The study of the electrical conductivity of reduced graphene oxide-containing composites showed electrical conductivity above the percolation threshold with a small content of graphene oxide (0.28 wt.%). This electrical conductivity makes it possible to produce sintered ceramics by electrical discharge machining (EDM), which significantly reduces the cost of manufacturing complex-shaped products. Besides improved mechanical properties and EDM machinability, 0.28 wt.% rGO composites demonstrated high resistance to hydrothermal degradation.

Aim: The present paper aims to systematize data concerning the prevalence and risk of dental erosion (DE) in adult patients with gastroesophageal reflux disease (GERD) compared to controls. Materials and methods: Core electronic databases, i.e., MEDLINE/PubMed, EMBASE, Cochrane, Google Scholar, and the Russian Science Citation Index (RSCI), were searched for studies assessing the prevalence and risk of DE in adult GERD patients with publication dates ranging from 1 January 1985 to 20 January 2022. Publications with detailed descriptive statistics (the total sample size of patients with GERD, the total sample size of controls (if available), the number of patients with DE in the sample of GERD patients, the number of patients with DE in the controls (if available)) were selected for the final analysis. Results: The final analysis included 28 studies involving 4379 people (2309 GERD patients and 2070 control subjects). The pooled prevalence of DE was 51.524% (95 CI: 39.742–63.221) in GERD patients and 21.351% (95 CI: 9.234–36.807) in controls. An association was found between the presence of DE and GERD using the random-effects model (OR 5.000, 95% CI: 2.995–8.345; I2 = 79.78%) compared with controls. When analyzing studies that only used validated instrumental methods for diagnosing GERD, alongside validated DE criteria (studies that did not specify the methodologies used were excluded), a significant association between the presence of DE and GERD was revealed (OR 5.586, 95% CI: 2.311–13.503; I2 = 85.14%). Conclusion: The meta-analysis demonstrated that DE is quite often associated with GERD and is observed in about half of patients with this extremely common disease of the upper gastrointestinal tract.

This paper discusses the results of a study focused on the nature of the interaction of Me-MeN-(Me,Mo,Al)N coatings (where Me = zirconium (Zr), titanium (Ti), or chromium (Cr)) with a contact medium based on the Ni-Cr system. The studies were carried out during the turning of nickel–chromium alloy at different cutting speeds. The hardness of the coatings was found, and their nanostructure and phase composition were studied. The experiments were conducted using transmission electron microscopy (TEM), X-ray diffraction (XRD), and selected area electron diffraction (SAED). According to the studies, at elevated cutting speeds, the highest wear resistance is demonstrated by the tools with the ZrN-based coating, while at lower cutting speeds, the tools with the TiN- and CrN-based coatings had higher wear resistance. At elevated cutting speeds, the experiments detected the active formation of oxides in the ZrN-based coating and less active formation of oxides in the CrN-based coating. No formation of oxides was detected in the TiN-based coating. The patterns of cracking in the coatings were also studied.