[The results of the study of the focus of initial caries of human tooth enamel in vitro using atomic force microscopy].

Objective: Identify structural disorders of the surface of the enamel of a human tooth during the development of the carious process in the «white spot» 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 spot» and in the immediate vicinity of it. The heterogeneity of the enamel surface in the center of the white spot» 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.