ADHESION AND COMPARATIVE ASSESSMENT OF "MERON" AND "TOTAL-CEM" CEMENTS TO DENTIN, KHS ALLOY AND PRESS CERAMICS IPS E.MAX PRESS

Abstract

The aim of the study. Comparative evaluation of glass ionomer cements «Meron», «Total-Cem» to dentin, KHS alloy and press ceramics IPS e.max Press. Research materials and methods. Experimental studies were conducted on 5 samples obtained by removing single-channel teeth and 5 separate measurement results were obtained: A1, A2, A3, A4, A5. Posts made of KHS alloy and IPS e.max Press press ceramics were fixed in the root canals using Meron and Total-Cem fixing cements. The posts were provided with fasteners for installation in a breaking machine. Scientific novelty. The intensity of electron transfer and, consequently, the surface density of separated charges, which determines the strength of the adhesion of glass ionomer cements to metals, depends not only on the concentration of free charges in metals, but also on the concentration of their capture centers in the cement. Such free charge capture centers in Meron glass ionomer cement can be chain breaks, free radicals, unsaturated bonds and other defects in the cement structure. The concentration of such defects depends on the strength of single bonds in glass ionomer cements. Such single bonds are C-H and C-C bonds. Their rupture energy depends on the chain structure and is 80 - 95 kcal/mol. These bonds are purely covalent in nature and in the case of their rupture, the carbon atom in the chain remains an unpaired electron, due to which it can form a covalent bond with the metal atom of the inlay. Conclusions. Adhesion of glass ionomer cements with various metals and alloys is determined by the physical and chemical properties of the oxide layer formed on the surface of the metals. In particular, the higher the electrical conductivity of the oxide layer and the greater the concentration of the main Lewis centers in it, the higher the adhesion of SIC to metals. The bond strength with enamel is always higher than with dentin due to the higher content of inorganic substances and higher homogeneity.