N 6 (197) 2025. P. 23–31

MODERN VIEWS ON MICROSTRUCTURE AND FUNCTIONS OF TOOTH DENTIN

N. О. Gevkaliuk, L. D. Tupol, N. I. Sydliaruk, V. M. Mykhailiuk, M. Ya. Pynda, V. Ya. Krupei

Ivan Horbachevsky Ternopil National Medical University of the Ministry of Health of Ukraine, Ternopil, Ukraine

DOI 10.32782/2226-2008-2025-6-3

The question of morpho-functional features of dentin and the microstructural composition of its components remains open to this day, therefore requiring in-depth study.

The aim of the study was to examine the microarchitecture of the structural-functional unit of dentin and evaluate the functions of its components – dentinal tubules, odontoblast processes, and microfibrillar apparatus.

Materials and methods. 27 intact teeth, extracted for orthodontic indications, were studied, from which samples were prepared for transverse and longitudinal fractures. Samples were immersed in Karnovsky’s fixative solution, washed in cacodylate buffer and demineralized. Dried samples were impregnated with epoxy resin in a VUP-5M vacuum device (VO “SELMI”, Sumy, Ukraine), impregnated with 20% silver nitrate solution and examined using a MICROmed Evolution ES-4140 light optical microscope (“Micromed”, Ukraine). After lyophilization by freezing, samples were prepared using the critical point drying method, mounted on copper tables with electrically conductive adhesive, coated with a 20 nm layer of chemically pure aluminum [grade 999], and examined in a “JEOL-25M-T220A” scanning electron microscope (Tokyo, Japan).

Results. The examination of tooth sections at the light optical level with silver nitrate solution impregnation allowed us to describe for the first time the presence of four dentin bands (black, dark, gray, light) of varying width and staining intensity, which was confirmed by scanning electron microscopy. The obtained SEM data indicate the absence of a fibrillar network and filling of the dentinal tubule lumen with crystalline substance during gradual atrophy of the dentinal tubules, which is manifested by the formation of gray and light dentin bands. The middle zone of dentin is visualized with well-preserved dentinal tubules and their collagen fibril systems, creating the appearance of a black band due to good absorption of silver ions.

Key words: dentin, dentinal bands, fibrillar apparatus, dentinal canaliculus, dentinal tubule.

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