Multi-functional Denture Liner Using Divinyl Sebacate/PEMA Paste

Objectives: This investigation seeks to develop a versatile denture liner, containing no alcohol or phthalate (a known endocrine disruptor) additives. Combination of an aliphatic vinyl ester (VE) and poly(ethyl methacrylate) (PEMA) powder provides a paste that enables a single material to offer a variety of properties and application options depending on the processing conditions used. Methods: Under ambient conditions, a soft denture liner was prepared by mixing PEMA powder (M.W.: 4 x 10⁵, Particle size: 40μm) and divinyl sebacate (DVS) as an aliphatic VE at the P/L ratio of 6/5 (g/ml). Alternately, a hard denture liner was prepared by thermo-polymerization (100°C, 1 h) of the DVS/PEMA paste. The viscoelasticity of soft denture liner was evaluated based on the stress relaxation behavior measured using a rheometer at 25°C. The flexural mechanical properties of the hard denture liner were evaluated using a universal testing machine. Results: At 2 h after ambient mixing, the viscoelastic behavior of the soft denture liner obtained from the DVS/PEMA paste was equivalent to that of four commercial tissue conditioners (TC). The modulus of DVS/PEMA paste immersed in distilled water at 37°C for 2 weeks decreased by 14% compared with the initial value measured at 2 h after mixing. However, the modulus values for the series of commercial TC materials increased by 85 to 269% with storage relative to their initial values. The flexural properties of the thermo-polymerized DVS/PEMA paste were compared with four types of commercial hard denture liner materials. The flexural strength of commercial hard denture liners ranged from 28 to 58MPa. The flexural strength (62±1MPa) of thermo-polymerized DVS/PEMA paste was equivalent to the strongest commercial hard denture liner. (Tukey p<0.05) Conclusion: Based on processing conditions, the novel denture liner composed of DVS and PEMA succeeds in controllably providing varied use-specific properties from the same material.