[Morphological study of enamel and dentin teeth with carious process and non-carious lesions]

Introduction: The condition of hard teeth tissues while choosing treatment method becomes particularly important due to the large development of adhesive technologies and the choice of filling materials. The quality of adhesion is one of the key factors that affects effectiveness of the entire range of therapeutic interventions, that determines the success of therapeutic treatment and the reliability of therapeutic restorations fixation. The aim of the work is to study the condition of hard teeth tissues in carious and non-carious pathology for further rationale of the choice of filling material and adhesive system.

Materials and methods: A thorough examination included teeth that were removed according to the indications. The age of patients, whose teeth were examined, was 25-55 years old according to the classification of age periods adopted at the International Symposium on the Age Periodization (Moscow, 1965). We conducted a morphological study of enamel and dentin of teeth with carious and non-carious lesions (increased erasability, cuneal defects), by obtaining chips and microsections of teeth, followed by examination of the number of enamel prisms, dentinal tubules,their diameter, the thickness of the gaps between these structures. The studies were carried out using a scanning electron microscope (SEM) "Mira 3 LMU" ("Tescan", Czech Republic) with a maximum resolution of 1 nm and a maximum magnification of 1,000,000. Dentally removed teeth were washed in running water, cleaned of plaque, dried by filter paper and crushed by vice, that was followed by the selection of the wreckage for the study. Then, markings in the dentine and enamel zones were made to fix the sizes of enamel prisms and dentinal tubules.

Results: After the completion of the determination of enamel prisms and dentinal tubules diameter, counting of their number was carried out according to the method proposed by I.M. Tkachenko, by obtaining a series of digital images of the examined tooth's enamel and dentin with varying degrees of magnification. The number of prisms per unit area characterized the enamel density, on which permeability, hardness, tissue resistance to fracture, bending and modulus of elasticity depends. The number of dentinal tubules characterized the density of dentin and the peculiarities of trophic processes that occur in dentin. Also, in our opinion, the amount of dentinal tubules determines the damping properties of dentin and strength enamel values.

Conclusions: Thus, the structure of enamel and dentin has peculiarities of the morphological structure at various clinical conditions of hard teeth tissues. This peculiarity can be associated with a decrease of enamel density, that is associated with a decrease in the number of prisms in the non-carious teeth pathology and an increase of the gaps between them.