Gastric cancer continues to be an important healthcare problem from a global perspective. Most of the cases in the Western world are diagnosed at late stages when the treatment is largely ineffective. Helicobacter pylori (H. pylori) infection is a well-established carcinogen for gastric cancer. While lifestyle factors are important, the efficacy of interventions in their modification, as in the use of antioxidant supplements, is unconvincing. No organized screening programs can be found outside Asia (Japan and South Korea). Although several screening approaches have been proposed, including indirect atrophy detection by measuring pepsinogen in the circulation, none of them have so far been implemented, and more study data is required to justify any implementation. Mass eradication of H. pylori in high-risk areas tends to be cost-effective, but its adverse effects and resistance remain a concern. Searches for new screening biomarkers, including microRNA and cancer-autoantibody panels, as well as detection of volatile organic compounds in the breath, are in progress. Endoscopy with a proper biopsy follow-up remains the standard for early detection of cancer and related premalignant lesions. At the same time, new advanced high-resolution endoscopic technologies are showing promising results with respect to diagnosing mucosal lesions visually and targeting each biopsy. New histological risk stratifications (classifications), including OLGA and OLGIM, have recently been developed. This review addresses the current means for gastric cancer primary and secondary prevention, the available and emerging methods for screening, and new developments in endoscopic detection of early lesions of the stomach.

Aim. The research was designed to assess the capabilities of the microcomputer tomography method with the subsequent image analysis and determination of the mineral optical density of demineralized areas to improve the early diagnosis of fissure caries of permanent molars after the eruption.Materials and methods. Using a high-resolution X-ray microtomograph “Skyscan 1176” (“Bruker”, Belgium) followed by post-processing and analysis of the obtained tomograms, 75 molars of children aged 8-11 were removed by orthodontic indications. Of the total number of teeth removed, research groups were formed – teeth without signs of demineralization and teeth with carious lesions in the stage of white, light brown, brown and black spots. In the reconstructed 2D and 3D images were identified the zones in the outer (0.05-0.5 mm), middle (0.75-1.25 mm) and inner (1.5-2.0 mm) thirds of the thickness of the enamel layer followed by the computation in the CTvox program (3.3.0-1403, Bruker-micro CT) of the averaged X-ray (mineral) density indicators. Results. According to the tomograms of the teeth of the studied groups, the average indicators of the mineral optical density of the intact teeth enamel were identified as well as the average indicators of teeth with various types of carious lesions within the enamel. The following sequence was revealed in descending order of the parameters of optical density: healthy enamel (2.47±0.12 g/cm3) – caries in the white spot stage (2.41±0.11 g/cm3) – caries in the light brown spot stage (2.32±0.07 g/cm3) – caries in the brown spot stage (2.18±0.12 g/cm3) – caries in the black spot stage (1.81±0.12 g/cm3). Identifying the correlations between the color of carious lesion and mineral density of tooth enamel broadens the understanding of the mechanisms of the development of caries pathogenesis and contributes to the improvement of therapeutic and preventive measures aimed at improving caries resistance.Conclusion. The use of microcomputer tomography in combination with other special methods characterizes fissure caries as a sequential, gradually progressing destructive process of hard tooth tissues (from focal demineralization to cavity formation), which establishes the relationship between the intensity of internal disturbances and external damage.

Aim. In this research, we aimed to investigate the caries resistance of permanent teeth in children at different dentition periods on the basis of data obtained on the chemical composition and microstructure of the tooth surface at the stage of tertiary mineralization.Materials and methods. We examined 34 premolars without signs of carious lesions, which had been extracted from 11–16 old children following indications for orthodontic treatment, using a high-resolution scanning electron microscope JSM-6610LV (JEOL) equipped with a micro X-ray spectrometer INCA Energy 350XT (Oxford Instruments Analytica, UK). The teeth under study were divided into three groups. The 1st, 2nd and 3rd groups comprised teeth extracted from 11–12, 13–14 and 15–16 year-old children, respectively. In these groups, tooth mineralization continues 6–12, 13–36 and 37–60 months after eruption, respectively.Results. The X-ray microanalysis of the teeth under study in terms of chemical composition (percentage by mass) showed that the surface enamel accumulates increased concentrations of Ca, P, F and demonstrates a higher Ca/P ratio under reduced levels of C, Na, O during mineralization. It is found that, during early stages of physiological maturation, tooth enamel shows morphological signs of hypo-mineralization, as well as a low caries- and acid resistance, due to its insuffi ciently formed prismatic structure, lack of a protective layer, signifi cant permeability and a large number of retention points.Conclusion. The obtained results demonstrate the possibility of applying high-resolution electron microscopy and X-ray microanalysis for the study of dental hard tissues in dental practice. The development and implementation of personalized approaches to the prevention of caries, which are based on the selective use of remineralizing preparations and vitaminmineral supplements, can increase the caries- and acid resistance of tooth enamel at all stages of its physiological maturation.