Comparative Evaluation of Mechanical and Physical Properties of Dental Cements for Permanent Fixation of Orthopedic Dentures

Fixation of dentures to permanent cement is the final clinical stage of orthopedic treatment. It should be noted, the result of the prosthesis with the use of any non-removable design essentially depends on the correct choice of cement for fixation. Research of physico-mechanical, clinico-technological and physico-chemical properties of materials was carried out according to the following parameters: film thickness, working time and hardening time, compression strength, water absorption and water solubility, bending strength, adhesion strength, adhesion to metal, adhesion to ceramics, adhesion to dentin and adhesion to enamel. Material and methods. For comparison, the following materials were investigated: glass ionic cements («Ketac Cem Easymix», 3М ESPE, Minnesota, the USA; «Cemion-F», Vladmiva, Russia), composite cements («Maxcem Elite», Kerr, California, the USA; «Bifix QV», VOCO, Cuxhaven, Germany; «G-Cem Capsula», GC, Japan), compomer cements («Permacem 2.0», DMG, Japan; «Relyx U 100», 3М ESPE, Minnesota, the USA). Measurement of the values of properties was carried out on 140 samples (20 samples from each material) using the methods provided by international ISO standards. Results and discussion. The adhesion (MPa) of dental cements for permanent fixation to precious metals ranges from 2.5 to 12.36 MPa, which fully meets the international requirements. The highest values of the index of adhesion to precious metals were characterized by cements: "Bifix" and "Permacem 2.0" – 12.36 and 11.00 MPa, respectively. We found out that the adhesion (MPa) of dental cements to non-precious metals has a limit of 14.0 to 22.0 MPa, which also meets international standards (more than 5 MPa). It was also proved that the adhesion (MPa) to the ceramics of these materials varies from 6.0 to 21.6 MPa, which corresponds to ISO standards. The worst indicators for adhesion to ceramics were the materials «Maxcem Elite» and «G-cem» 6.0 and 6.2 MPa. Conclusions. The data obtained in the complex of clinical and laboratory studies indicate that cements for permanent fixation of non-removable orthopedic dentures selected for comparison, comply with international ISO standards. The highest adhesion indexes of glassy ionomer cements were for non-precious metals. So in this case we recommend using glassy ionomeric cements. Double curing cement is recommended when fixing full ceramic structures.