Ageing processes in laser sintered and injection moulded PA12 following hygienic reprocessing.

Purpose -- The purpose of this paper is to describe the ageing behaviour of polyamide 12 (PA12) after clinical use. The research is focused on the comparison of the processing methods injection moulding and laser sintering. Design/methodology/approach -- Test specimens are subjected to a cyclic stress of defined bending, cleaning, disinfection and sterilization. The focus of interest in this research is the degradation and reduction of mechanical properties. Findings -- Mechanical and optical changes of the materials after clinical use and hygienic reprocessing are evaluated and discussed. Research limitations/implications -- This article is focused on PA12 and, therefore, enables a very specific statement for the clinical use of PA12. The processing methods could have different impacts depending on the polymer. Originality/value -- With the increasing application of polymers in medical devices, the mechanical properties must be ensured even after long-term clinical use. A systematic research with a realistic and still-defined cyclic stress is shown in this paper. Especially the testing of laser sintered polymers compared to injection moulded material has an important message for future patient-specific products. [ABSTRACT FROM AUTHOR]