The Acrylic Bone Cement in Arthroplasty

Otto Rohm is known as the developer of polymethylmethacrylate (PMMA) in 1901. Industri‐ al-size chemical synthesis of MMA was achieved in the 1920s in the laboratories of Rohm and Haas, and the first biomedical applications of PMMA was the fabrication of dentures. In the 1930s it was discovered that the mixing of MMA monomer and benzoyl peroxide initia‐ tor with prepolymerized PMMA powder resulted in the formation of a dough-like material which could slowly harden into a glassy polymer. This two-component polymer (cement) was initially used to close cranial defects. Because of the transparency, strength, and stabili‐ ty of polymethylmethacrylate, the commercial production of cast sheets of it in the early 1930s led to its utilization as a denture base and prosthetic material. Originally pieces of the material were molded under heat and pressure.[1, 2, 3] In 1935, an injection molding techni‐ que was introduced by ICI for dentures in which the melted PMMA was injected into dried plaster molds under hydraulic pressure. These techniques proved to be too cumbersome. In 1936, as was mentioned above, it was discovered that mixing of methyl methacrylate mono‐ mer with the ground polymer produced a dough that could be shaped in plaster molds and could be polymerized into a solid mass by using benzoyl peroxide as a polymerization ini‐ tiator. In the next few years, it was found that improved molding characteristics could be obtained using a powder that was a mixture of ground and spherical (bead) polymer parti‐ cles.[1, 2]