Mechanical and Tribological Properties of PMMA-Sea Shell based Biocomposite for Dental application

The material used for fabricating dentures should have good mechanical and tribological properties in order to withstand heavy forces inside the mouth. A study has been made to evaluate the hardness and tribological properties the Poly (Methyl methacrylate) PMMA based denture composite reinforced with seashell nanopowder. The PMMA biocomposites containing 2%, 4%, 6%, 8%, 12%, 16% and 20% by weight of seashell nanopowder and an unfilled composite as control specimen were fabricated. The microhardness of the composites was found using Vickers hardness tester. The addition of 2% seashell nanopowder had no significant effect on the microhardness. But it was found that on increasing the seashell nanopowder content, the microhardness value increased till 12% and substantially decreased beyond 12% seashell nanopowder. The wear test was performed and frictional force generated during sliding of specimens were evaluated in pin on disc apparatus. The wear mechanism and dispersion of seashell nanopowder in the specimen were analyzed in Scanning Electron Microscopy (SEM). The wear resistant property increased on addition of seashell nanopowder with 12% seashell nanopowder reinforced composite showing least frictional force developed during the wear test. The 16% and 20% filled composite developed more frictional force than developed in 12% filled composite. It was concluded that PMMA biocomposite could be successfully reinforced by seashell nanopowder with better properties at 12% seashell nanopowder content followed by 8% filled composite.