Development of butyl elastomer/methacrylate monomer systems as denture soft lining materials

Previous studies have shown elastomer/methacrylate monomer formulations to have good strength; however, water uptake was high and they also suffered from oxidation. This study has looked at the use of three different butyl elastomers, well known for their oxidation resistance, butyl (PB), chlorobutyl (PCB) and bromobutyl (PBB). The tensile and water uptake properties of the three elastomers gelled with ethyl hexyl methacrylate containing 1% ethylene glycol dimethacrylate and 1% lauryl peroxide (5+ formulation from previous studies) were studied. Water uptake of the pure elastomers was also measured. Tensile strengths were low (PCB5+ = 3.09+/-0.12 MPa and PBB5+ = 3.90+/-0.36 MPa); however, elongation to break values were high (PCB5+ = 797+/-17% and PBB5+ = 599+/-13%). Water uptake was high and protracted with none of the formulations reaching equilibrium. The PCB5+ had the highest uptake (approximately 6% at 203 days) with that for PBB5+ and PB5+ at a similar level (approxiamtely 4% at 203 days). None of the materials showed any sign of oxidation. The PBB proved to be the most suitable of the three elastomers for further development in soft lining formulations.