[Application of autofluorescence microscopy and laser Induced fluorescence methods to study the dynamics of the demineralization primary teeth process in vitro].

Objective: Improvement of methods for studying the processes of demineralization of hard tissues of temporary teeth.

Material and methods: The study included primaries second molars (n=11). Samples of primary teeth were placed in a test tube with a demineralizing solution for - 1, 4, 8, 21 and 31 days. The of primary teeth samples were examined using methods - laser induced fluorescence (LIF) and autofluorescence microscopy (AFM). Assessment of the degree of demineralization of samples of temporary teeth was carried out according to the score scale developed by us.

Results: The enamel of the samples is demineralized slowly and evenly for up to 8 days with minimal objective signs, starting from the 8th day of the experiment, there is a significant increase in demineralization indicators. By the 21st day, the peak of demineralization is reached with partial dissolution of the enamel, an increase in the fluorescence effect to 80 UE, and reaches a maximum of 4 points on the evaluation scale. Dentin's hard tissues are demineralized gradually without "sudden jumps" in the fluorescence effect and at the same rate throughout the experiment, reaching a maximum on 31 days (30 UE - LIF). Dentin demineralization is characterized by less dissolution, however, the phenomenon of delamination is determined by the type of exfoliation of the organic dentin matrix, starting from the 21st day of the experiment.

Conclusion: Enamel and dentin of deciduous teeth demineralize at different rates and have a characteristic specificity of morphological changes. Logistic regression analysis showed the consistency of the classifier for the predictive accuracy of each unit of the proposed scale for assessing the degree of demineralization of temporary teeth samples.