Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties

The aim of the study was to evaluate the effect of adding acrylamide monomer (AAm) on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly(methyl methacrylate) (PMMA) denture-base resins. Specimens (n=10) were fabricated from a conventional heat-activated QC-20 (Qc-) and a microwave heat-activated Acron MC (Ac-) PMMA resins. Powder/liquid ratio followed the manufacturer’s instructions for the control groups (Qc-c and Ac-c) and for the copolymer groups, the resins were prepared with 5% (−5), 10% (−10), 15% (−15) and 20% (−20) acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal–Wallis test (α=0.05) to determine significant differences between the groups. The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis (TGA) with a heating rate of 10 °C⋅min−1 from 35 °C to 600 °C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c (P<0.01). Ac-10 and Ac-15 showed significance when compared to Ac-c (P<0.01). Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c (P<0.01). Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c (P<0.01). According to the 1H-nuclear magnetic resonance (NMR) results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm. A small chemical compound can have a big impact on the stability of polymers for denture bases, according to Turkish scientists. Acrylic polymers such as polymethyl methacrylate (PMMA) find wide use in dental restoration because they are easy to fabricate and feel comfortable in the mouth. Their less-than-ideal mechanical properties, however, make PMMA dentures prone to fracture. Elif Aydogan Ayaz and Rukiye Durkan from Karadeniz Technical University compared traditional PMMA denture bases to ones incorporating varying amounts of acrylic acid, a reactive molecule that can cross-link polymer fibers together. Tests that simulated chewing motions showed that acrylic acid additions significantly reduced polymer fatigue by improving the material’s resistance to bending. Their quantitative chemical analysis revealed that efficient co-polymerization between PMMA and acrylic acid provides much-needed reinforcements to the denture base.