Soft acrylic resin materials containing a polymerisable plasticiser I: mechanical properties.

Conventional soft acrylic resin materials depend on the use of plasticisers for their compliance. In aqueous environments the plasticisers leach out causing the material to harden. Use of a polymerisable plasticiser has been shown to solve this problem. One such material was developed but failed mechanically during clinical trial. The aim of this study was to reformulate to produce a material with improved strength. Three different methacrylate monomers were used with two different levels of plasticiser, each monomer mix was used with the same copolymer powder at three powder/liquid ratios. Tensile strength, tear energy and hardness were measured and results compared with 'Supersoft', a proprietary plasticised acrylic resin soft lining material. All the experimental materials had a higher tensile strength than the original Parker/Braden material. The 30% plasticiser materials with the higher powder/liquid level had strength, tear energy and hardness values in the same range as 'Supersoft'. Materials of improved strength have been produced.