Background. Breakthrough resolutions in current biopolymer engineering rely on reliable diagnostics of atomic-deficient spaces over the finest sub-nanometer length scales. One such diagnostic is positron annihilation lifetime spectroscopy, which probes space-time continuum relationships for the interaction between electrons and their antiparticle (positrons) in structural entities like free-volume defects, vacancies, vacancy-like clusters, interfacial voids and pores, etc.

Light-curing volumetric shrinkage in dimethacrylate-based dental resin composites Dipol® is examined through comprehensive kinetics research employing nanoindentation measurements and nanoscale atomic-deficient study with lifetime spectroscopy of annihilating positrons. Photopolymerization kinetics determined through nanoindentation testing is shown to be described via single-exponential relaxation function with character time constants reaching respectively 15.0 and 18.7 s for nanohardness and elastic modulus. Atomic-deficient characteristics of composites are extracted from positron lifetime spectra parameterized employing unconstrained x3-term fitting. The tested photopolymerization kinetics can be adequately reflected in time-dependent changes observed in average positron lifetime (with 17.9 s time constant) and fractional free volume of positronium traps (with 18.6 s time constant). This correlation proves that fragmentation of free-volume positronium-trapping sites accompanied by partial positronium-to-positron traps conversion determines the light-curing volumetric shrinkage in the studied composites.

Introduction. The development of inflammation in the periodontium is inextricably linked to the system processes in the organism, including an accompanying pathology, which is often parallel. The WHO particularly emphasizes the dissemination of overweight among children. Against the background of excessive weight gain in children there are the series metabolic disorders that provoke chronic diseases, including chronic catarrhal gingivitis.Aim. The aim of this study was to identify the dynamics of cytokines (IL-4, IL-6) in oral fluid and characterize the immune system of the oral cavity in children with overweight and obesity.Material and Methods. This study presents the results of examination of 80 children with overweight and obese patients with chronic catarrhal gingivitis (CCG), aged 12–15 years. Based on anthropometric surveys body mass index (BMI) was calculated. Also the obtained measurements and calculations were evaluated by percentile tables that were designed by the WHO in 2007 for children and adolescents 5 to 19 years for both sexes separately (WHO, 2007). The content of interleukin (IL-4; IL-6) in oral fluid in children was determined by using kits of reagents of company "Vector‑Best" (Russia), based on solid‑phase "sandwich" variant of immunoenzyme analysis.Results. The level of IL-4 in the oral fluid of children with chronic catarrhal gingivitis decreases (1.8 times) with increasing of age and with the deepening of violations of fat metabolism. The level of IL-6 in the oral fluid of children with chronic catarrhal gingivitis increases (2.9 times) with increasing of age and the presence of excess body weight and obesity.Conclusions. Further study of interleukin imbalance in the oral fluid of patients with chronic catarrhal gingivitis and overweight is a promising area of research to develop methods of prevention and pathogenic therapy.

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Evaluation of the dental status of children with overweight showed that carious lesions of teeth and periodontal disease occur more often compared to healthy children.The aim of the study – to determine the factors and indicators of the risk of carious disease and periodontal disease in overweight children and adolescents.Materials and Methods. In the analytical epidemiology, the EGOHID-2005 system was used. Two key age groups of 100 schoolchildren in each of 12 and 15 years old were studied in Lviv.Results and Discussion. The main factors, that determine the different intensity of carious disease and periodontal tissue diseases, were differences in the children's compliance with the recommended regime of tooth brushing, the use of fluorine-containing toothpastes and frequent consumption of sugary foods and beverages.Conclusions. The system of European indicators of dental health EGOHID is quite informative in identifying risk factors for bleeding gums and dental caries in overweight children and adolescents.