MORPHOLOGICAL CHANGES IN TOOTH DENTIN AT VARIOUS STAGES OF ABRASION AND THEIR IMPACT ON THE CHOICE OF ORTHOPEDIC TREATMENT

Introduction. The severity of orthopedic treatment of patients with pathological abrasion of hard dental tissues is due to the progressive development of abrasion, an increase in the free interocclusal space, a decrease in the interalveolar distance and the size of the lower part of the face. The microstructure and microelement composition of hard dental tissues reflect complex processes associated with age-related and pathological conditions in the body. Aim. In view of the above, the objective of this study was to study the morphological changes in tooth dentin with different degrees of abrasion and their influence on the choice of orthopedic treatment. Materials and methods. The study of the enamel and dentin structure features was carried out on thick and thin tooth sections. The sections were then stained with the SHIK reaction followed by additional staining with alcian blue. Histochemically stained types of dentin are studied at different magnifications in reflected rays (epicyroscopy). Results. It was established that replacement dentin is formed both due to different degrees of mineralization of dentinal tubules and adjacent intertubular dentin. The latter determines the progression or extinction of the pathological process and can be determined by histochemical staining. We have established that the so-called "dead zone" in the third degree of pathological abrasion of regular dentin is constantly adjacent to a well-defined predentin zone. The latter is characterized by the presence of thin SHIK-positive fibers, tangentially located to the dentinal tubules. Sometimes minicracks are adjacent to the dead zones of dentin, located tangentially to the dentinal tubules, which indicates necrobiosis phenomena. Conclusions. It has been established that at the third degree of pathological abrasion, significant tissue restructuring of the pulp and the formation of denticles in it are observed, partially or completely blocking the lumen of the tooth cavity. In the preserved areas of the pulp, necrobiotic processes are noted and obliteration of the root canals occurs due to excessive deposition of lime salts. Teeth with the third degree of pathological abrasion are not suitable for prosthetics without appropriate therapeutic and orthopedic preparation due to the development of pronounced organic changes in the pulp and hard tissues of the tooth.