[The results of the study of the focus of initial caries of human tooth enamel in vitro using atomic force microscopy]. / Rezul'taty issledovaniya ochaga nachal'nogo kariesa emali zuba cheloveka in vitro s pomoshch'yu atomno-silovoi mikroskopii.

OBJECTIVE: Identify structural disorders of the surface of the enamel of a human tooth during the development of the carious process in the «white spot¼ stage using atomic force microscopy (AFM). MATERIAL AND METODS: The studies were carried out on 10 molar samples in areas with initial caries in the white spot stage. 6 areas of initial caries were scanned using the atomic force microscope Cetus Light (Nano Scan Technology, Russia) in semi-contact mode. Criteria were proposed for comparing the results of AFM scanning of tooth enamel surface samples and, based on them, the nature of the main structural disorders of the enamel surface in the affected area was determined. RESULTS: For all the samples studied, the healthy enamel surface was smoother compared to the enamel in the area of the clinically visible «white spot¼ and in the immediate vicinity of it. The heterogeneity of the enamel surface in the center of the white spot¼ for all the samples studied was at least 60% higher than at the edge of the process. It was revealed that the heterogeneity of the surface outside the clinically visible white spot at a distance of less than 1 mm from its perimeter is at least 30% higher than that of healthy tissue of the same tooth. It is shown that the heterogeneity of the enamel surface in the center of the caries area in the white spot stage is at least 4 times greater than the heterogeneity of the surface of the healthy enamel of the same tooth, which indicates its demineralization. CONCLUSION: The established features of the spread of the initial carious process can be used in clinical practice for the diagnosis and dynamic observation of the processes of enamel demineralization.

[Ultrastructural changes of human dental hard tissues during orthodontic treatment with fixed appliances]. / Issledovanie ul'trastrukturnogo sostoianiia tverdykh tkanei zuba pri éksperimental'nom modelirovanii ortodonticheskogo lecheniia nes''emnoi apparaturoi.

The aim of the study was to evaluate ultrastructural changes of dental enamel after fixation of orthodontic appliances, initial influence of orthodontic forces and removal of braces. Five intact permanent tooth extracted for orthodontic reasons were included in the experimental study. Scanning probe microscopy was conducted in 4 random enamel points in each tooth (20 points overall) in semi-contact mode with standard 10 nm probes. The study showed ultrastructural enamel changes such as nanofractures up to 1 mm along the braces locks. The changes correlated with surface morphological features and teeth anatomy and may play an important role in dental decay and non-carious lesions occurring in the course of orthodontic treatment.

[Evaluation of dental hard tissues by means of atomic force microscopy].

The paper presents modified method of teeth slice preparation for evaluating enamel and dentin morphological structure by means of atomic force microscopy (AFM). The method allows measuring directly and describing hydroxyappatite crystals on nanolevel. Structural properties of dental hard tissues were determined and comparative characteristic of form and density of enamel prisms particles with similar morphological inorganic elements of dentin were specified.

[Peculiarities of the morphological structure of the inorganic component of human dental enamel and dentin at nano-level].

Using the polished sections of 20 permanent human molars and premolars, the regimes of probe atomic force microscopy were assessed that permit the definition of the size, shape, spatial configuration of the structure-forming hydroxyapatite crystals of enamel and dentin inorganic component. It was found that the major part of enamel crystals had the size of 40-60 nm and were more flattened. Dentin crystal average size was equal to 60-80 nm. Microspaces between them had the shape of rotational ellipsoid sized 120 nm by 60 nm.

[Sporadic juvenile forms of Huntington's chorea]. / O sporadicheskikh iuvenil'knykh formakh khorei Gentingtona.

Six patients with Huntington's chorea in the age of 15-24 years old, suffered from diffusive choreic hyperkynesis with slowly progressive dementia. The development of this disease in childhood and adolescence was atypical, as nobody in the family and in kin sufferred from it and it was difficult to diagnose the disease. Recognition of the disease was promoted by pneumoencephalography, electromyography and memory investigation.