Methylmethacrylate implants: a scanning electron microscopic study.

Two methylmethacrylate orbital implants used for 34 and 5 years, respectively, were examined with a scanning electron microscope. One of the implants was a combination of a prosthesis and an implant containing a magnet. The magnetic force had decreased markedly, and rust crystals were apparent. The methylmethacrylate surface was irregular and rough.