Journal of Biomaterials Applications

Polyurethanes have unique mechanical and biologic properties that make them ideal for many implantable devices. They are subject to some in vivo degradation mechanisms, however. Polyester polyurethanes are subject to hydrolytic degradation and are no longer used in long-term implanted devices. Polyether polyurethanes, while hydrolytically stable, are subject to oxidative degradation in several forms, including environmental stress cracking and metal ion oxidation. Mineralization is also known to occur. A new polycarbonate polyurethane has superior biostability in early in vivo qualification tests compared to the polyether polyurethanes, including no evidence of hydrolysis, ESC or MIO.

Testing of dental materials helps to ensure that they are of satisfactory quality. Most standardized testing programs have focused on the physical, chemical, and mechanical properties of the materials, and started at the National Bureau of Standards, USA, in 1919. The need for biological evaluation of dental materials became evident after some material-related adverse incidents. The first document concerning standardized testing of the biological properties of dental materials was published by the American Dental Association in 1972. During the last twenty-five years, increased attention has been focused on the evaluation of biological properties by standardized testing. The development of standards concerning biological testing of dental materials since 1972 at the national and international level is described.

Four types of polyurethane (PU) and two types of 2-polyhydroxyethylmethacrylate (PHEMA) membranes were prepared by convenient methods. Surface properties, water and antibacterial agent permeabilities of PU membranes were investigated. Water permeability values were determined in the region of 2000 g/m² * 24 h. The membranes were found to have sufficient permeability toward antibacterial agents of 1% Silver Sulfadiazine and Bacitracin 10,000 UI-Neomycin sulphate 100 mg ointment.

The concept of utilizing contract sterilization of medical devices. The advantages and disadvantages of utilizing contractors for the sterilization of disposable medical devices are presented, including the use of cobalt-60 gamma, electron beam, and ethylene oxide. A general update on the scope, activities, and capabilities of the contract sterilizer is included.