MICROSTRUCTURAL AND MICROMECHANICAL TESTS OF TITANIUM CROWNS

Abstract

Fixed prosthetic restorations must meet the health requirements in terms of the protection of the tissues of the oral cavity, biomechanical requirements for optimal tissue stress and the strength and wear resistance of the structure, aesthetic requirements related to the location of the gingival margin, as well as the shape, thickness, and colour of the veneers. The aim is to evaluate the impact of manufacturing technology on the microstructure and micromechanical parameters of titanium crowns. The material of the analysis are prosthetic crowns made of Ti6Al4V alloy for the maxilla premolars and the mandible molars, produced using two technologies: Selective Laser Melting (SLM) and CAD/CAM milling. Crown structures were evaluated on the basis of examinations of the microstructure and surface layer of the chamfers, micromechanical parameters in axial sections perpendicular to the dental arches, and the accuracy of mapping the internal shape in sections with horizontal planes perpendicular to the axis of the abutment tooth. The results of this work can be used in a clinical setting. They allow the evaluation of what is the impact of the technology of producing the supporting substructure on the structure of the prosthetic crown. The strength requirements in both technologies are met, while the higher value of the microhardness of the titanium SLM substructure, compared to the milled one, increases the stiffness of the structure under conditions of biomechanical excitation. The errors in mapping the internal shape of the crowns are comparable and slightly higher during sintering.