ANALYSIS OF ADHESION INTERACTION OF DISSIMILAR SURFACES IN THE TECHNOLOGY OF MANUFACTURING SINGLE ZIRCONIUM DIOXIDE CROWNS

Introduction. The use of zirconium dioxide in orthopedic dentistry has been recognized as a reference due to its high mechanical strength and biocompatibility. However, the effectiveness of restoration procedures is determined not only by the material characteristics but also by strict adherence to the technological steps of production and methods of surface preparation before fixation. Disturbances in CAD/CAM milling, sintering or adhesion processing can lead to deterioration of the adhesive properties, formation of microfractures and reduced durability. Objective. Optimization of the mechanical treatment parameters of solid dental tissues, core posts and inner surface of zirconia crowns to achieve maximum adhesive strength and durability of the structure. Methodology. An experimental study was carried out, the object of which were removed teeth with medical indications for prosthetics. The teeth were divided into three groups depending on the type of stump: an intact tooth, a tooth with a composite filling, and a tooth with a metal cast post-and-core made from a cobalt-chrome alloy. Preparation of specimens was carried out with the use of different grain-grade edges (50, 100, 150 μm), followed by the formation of micropropagation platforms. The inner surface of the crowns was sandblasted with 50 μm aluminium oxide. Specimen transformation was carried out with the use of different grain-grade edges (50, 100, 150 μm), followed by the formation of micropropagation platforms. The inner surface of the crowns was sandblasted with 50 μm aluminium oxide. Separation and heat cycling tests were performed. Parallel analysis of the technological steps of the production of crowns in laboratory conditions with simulation of typical errors was carried out. Results. It has been proven not to be effective in hardening zirconium dioxide with hydrofluoric acid. Maximum fastening strength is achieved in a group with metal tabs when combining 100 μm bur and 110 μm sandblast. The creation of microformation sites on the inner surface of the crowns increased strength. The optimal preparation protocol includes a 100 μm boron preparation, a 50 μm sandblasting of the crown and the formation of retention points. Conclusion. The developed mechanical preparation protocol, taking into account differences in source materials and operating conditions, demonstrates a significant increase in bond strength. Furthermore, this protocol ensures high resistance to thermal cycling while maintaining bond strength.