Page 181 - Clinical relevance of current materials for cranial implants

Sterilization Technique
Autoclavation
EtO HPGP γ-irradiation
Specifications
121 °C for 16 min or 134 °C for 3.5 min
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Sterrad
26.4 – 29.4 kGy from Cobalt-60
ISO norm
17665:2006
11135:2014 11737:2006 11137-1:2015
Effects of sterilization on the mechanical properties of PMMA
RESULTS
The results of the mechanical tests and the statistical analysis are summarized in Table 3 and representative curves for the flexural strength and toughness are graphically depicted in Figure 1. The autoclave-sterilized specimens were excluded from the results and the statistical analysis due to deformation or exfoliation during the sterilization process.
Table 1: Specifications of the sterilization methods (autoclavation, ethylene oxide (EtO), hydrogen peroxide gas plasma (HPGP) and γ-irradiation).
Figure 1: Force displacement graphs of representative flexural strength (left) and toughness (right) tested 9 specimens of Vertex Self-Curing (dot), Palacos R+G (dot-dash) and NextDent C&B MFH (dash).
Flexural strength and flexural modulus
NextDent C&B MFH had a significantly higher flexural strength (σ) for each sterilization method compared to the other materials. Vertex Self-Curing had a significantly higher flexural strength for γ-irradiation and HPGP compared to Palacos R+G. The flexural strength of γ-irradiated specimens was significantly higher than the otherwise sterilized and control specimens for all materials.
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