Tissue compatibility of methylmethacrylate in cranial prostheses: a preliminary investigation

An in vivo study using 48 disease-free male Lewis rats was conducted to determine the histologic difference between an alloplastic cranial prosthesis made with a monomer directly from the manufacturer and a triple-distilled monomer. The histologic difference in the tissue reaction between a cranial prosthesis sterilized with ethylene oxide and one sterilized with cobalt-60 irradiation was also evaluated. Histologic tissue biopsies of the cranium and brain tissues were obtained at 1, 3, 6, and 12 weeks. Tissue biopsies after the third week showed minimal inflammation and the microscopic findings were consistent with the reparative stage of wound healing. The findings also suggest that distillation of the monomer in heat-polymerized methyl-methacrylate is unnecessary for cranial prostheses. Cobalt-60 irradiation was found to be an effective alternative method of sterilization for such prostheses.