[Distinctions in molecular composition of the dental biofilm depending on the method of exo-/endogeneous caries prevention and cariogenic condition of a patient]. / Osobennosti molekulyarnogo sostava zubnoi bioplenki v zavisimosti ot metoda ekzo-/endogennoi profilaktiki kariesa i kariesogennoi situatsii u patsienta.

PURPOSE OF THE STUDY: For the first time distinctions of molecular composition of the dental biofilm at the stages of exo- and endogeneous caries prevention were studied for persons with different cariogenic conditions involving synchrotron molecular spectroscopy techniques. MATERIAL AND METHODS: The samples of the dental biofilm collected from participants of the research were studied at the different stages of experiment. The studies of molecular composition of the biofilms were employed involving the equipment set in the Infrared Microspectroscopy (IRM) laboratory of Australian synchrotron. RESULTS: Basing on the data obtained by synchrotron infrared spectroscopy with Fourier transform as well as using the calculations of the ratios between organic and mineral components and also statistical analysis of the data we could estimate the changes proceeding in the molecular composition of dental biofilm in a dependence of homeostasis conditions in the oral cavity at the stages of exo- and endogeneous caries prevention. CONCLUSION: Observed changes in the values of phosphate/protein/lipid, phosphate/mineral and phospholipid/lipid ratios as well as the presence of statistically significant intra- and intergroup in these coefficients mean that mechanisms of adsorption for the ions, compounds and molecular complexes incoming from the oral fluid into the dental biofilm at the stage of exo-/endogeneous caries prevention are different for the patients in normal condition and for those ones with the developing caries.

[Biomimetic strategy of a hybrid biointerface creation between native human dental tissue and dental composite]. / Biomimeticheskaya strategiya v osnove sozdaniya gibridnogo biointerfeisa mezhdu nativnoi zubnoi tkan'yu cheloveka i stomatologicheskim kompozitom.

OBJECTIVE: The aim of the studyis the peculiarities of the molecular composition of the biointerface between the native human dental tissue and the dental composite, created in an alkaline environment, based on synchrotron chemical infrared micro-mapping. MATERIAL AND METHODS: When creating a biomimetic interface under alkaline conditions, we used an original bioprimer, dentin conditioner, nanofilled universal adhesive, and a light-curing compomer based on BIS-GMA. RESULTS: Biointerface analysis was carried out on the basis of chemical infrared micro-mapping, implemented using the equipment of the Australian Synchrotron, and subsequent multivariate cluster analysis of the collected spectral data array. It was shown that the use of a primer modified with a set of polar amino acids additionally facilitated the opening of dentinal tubules and the penetration of the bioprimer components into the dentin with the formation of a deeper transitional hybrid layer. At the same time, modification of the Bis-GMA adhesive using nanocrystalline carbonate-substituted hydroxyapatite, which has a structural and morphological organization similar to natural dental tissue apatite, led to an increase in the degree of conversion of the used adhesive material during polymerization. CONCLUSION: Using a biomimetic strategy and nanocrystals of carbonate-substituted hydroxyapatite as a filler of a universal adhesive, the necessary conjugation at the interface with dentin can be achieved without disrupting the polymerization processes, as well as preserving the natural structural complexity of the intact tissue, which makes it possible to take into account the individual characteristics of the patient.

Investigations of porous silicon with deposited 3D-metals by Auger- and ultrasoft X-ray emission spectroscopy.

Nanocomposites based on porous silicon (Por-Si) with 3d-metals incorporated into pores can be used as magnetics. Por-Si layers were obtained by anodic etching of n-type silicon (100) with the use of HF solution in alcohol. Fe, Co, Ni galvanic deposition in por-Si was made from aqueous solutions of corresponding sulphates. We have shown by USXES (Ultrasoft X-ray emission spectroscopy), and Auger spectroscopy that Fe covers the surface of porous silicon uniformly but Co penetrates into pores depth. And Ni nanoparticles similar to Co penetrate into pores depth. The obtained Auger profiles of por-Si(Fe), por-Si(Co), por-Si(Ni) nanocomposites shown that its surface layers (to 40 nm) contain up to 10% Fe and no more than 1% Co and Ni, testifying about Co and Ni penetration into silicon pores depth.