Comparative Characteristics of the Properties of Polymer Materials Used for Manufacturing Temporary Dentures

The study was aimed at providing a comparative characterization of the properties of polymer materials used for manufacturing provisional fixed dentures applying traditional and digital methods. Water absorption and solubility of the materials were assessed. The experimental samples for the study were made of self-hardening cold-polymerized plastic based on polymethylmethacrylate Re-Fine Bright, a chemical-cured bisacrylic composite material Protemp 4, composite blocks made of acrylate polymer for Vita CAD-Temp CAD/CAM systems, and photopolymer resin for the NextDent C&B MFH 3D printer. The study was conducted in accordance with GOST 56924-2016 "Polymer reducing materials". Statistical analysis was performed using the Kraskel-Wallis and Mann-Whitney H-test. It was found that for the Re-Fine Bright material, the average water absorption was 14.94 ± 0.2748 micrograms/mm3, and solubility equaled 0.56 ± 0.1949 micrograms/mm3, for Protemp 4, the average water absorption was 9.259 ± 0.1719 micrograms/mm3, solubility was 0.46 ± 0.1673 micrograms/mm3, for Vita CAD–Temp, the average the value of water absorption equaled 9.649 ± 0.2305 micrograms/mm3, solubility was 0.36 ± 0.1517 micrograms/mm3, for NextDent C&B MFH, the average value of water absorption was 21.69 ± 0.1259 micrograms/mm3, solubility was 0.4 ± 0.2121 micrograms/mm3. The study allows us to conclude that the groups of materials studied are indistinguishable on the basis of the "Solubility" criterion and distinguishable on the basis of the "Water absorption" criterion with a significance level of p < 0.01. There were no statistical differences in the criterion of "Water absorption" between Vita CAD-Temp material, Re-Fine Bright plastic and Protemp 4 material. The water absorption rates for Protemp 4 were significantly lower compared to the ReFine Bright plastic (the median samples differ by 37,4 %, p < 0,0083). The samples made of photopolymer resin for the NextDent C&B MFH 3D printer had the highest water absorption value (the median of the sample was greater than the median of the groups "Protemp 4" by 61.1 %, that of "ReFine Bright" by 37.7 %, and that of "Vita CAD-Temp" by 51.8 %, p < 0.0083).