Comparative evaluation of the main properties of dental cements for permanent fixation of non-removable denture structures

The study was conducted to compare the main characteristics of dental cements for permanent fixation of fixed dentures. Some materials, formed by the reaction of weak polymeric acids with inorganic glass powder. Dental cements have a number of advantages: due to adhesion, the material "join" the surface of the abutment tooth and the inner surface of the artificial structure; some permanent cements slowly release fluoride ions over time to maintain dental health; they do not dissolve in the oral fluid. Despite the advantages, these materials need further improvement in their mechanical performance. Laboratory tests were carried out in the conditions of the accredited in the system of UKR-SEPRO and licensed research laboratory of JSC "Stoma". The following basic properties were studied: mixing time (Tm, s), curing time (Tc, s), film thickness (μm), compressive strength (MPa), acid solubility (mm/h), adhesion to metal/dentin (MPa). The process of mixing the components of the "Compomer" material is 2.5 s longer than that of "Ketac Cem" and 7.7 s longer than that of "Fuji Plus". In the case of the "curing time" indicator, the "Fuji Plus" material is significantly different, with a curing time that is 4.5 s faster than that of "Ketac Cem" and half the "curing time" compared to "Compomer". "Ketac Cem" has the lowest "film thickness" value – (21.8±0.8) μm, which significantly differs (p≤0.05) from the materials selected for the study. The study of the compression resistance of the cements revealed their full compliance with the standard value according to ISO-9917-1:2007. The acid solubility of the tested cements is at the level of (0.14÷0.29) mm/h. The adhesion index of the tested cements fully meets the requirements of international standards. Keywords: permanent cement, non-removable denture structures, properties, adhesion, international standards.