|
Bone cements based on poly methyl-methacrylate (PMMA) are among the most widely
used polymer composites in orthopaedic surgery. They play a key role in fixing the endoprosthesis
with the bone, and, as such, are the weakest link in total joint replacement (TJR) surgeries. A fast,
premature decrease in the mechanical properties of PMMA in an aggressive environment, such as the
human body, can lead to TJR loosening, which results in the necessity for revision surgery. In recent
years researchers have undertaken studies on the possibility of enhancing the mechanical properties of
PMMA by adding various admixtures in different concentrations. In this study we present the results
of the mechanical properties of samples made of the commercially available and widely used in
orthopaedic surgery PMMA bone cement (Palamed® Heraeus) that was admixed with glassy carbon
(GC) using different concentrations. All samples were subjected to compression testing. Compression
reflects the load mechanism acting on PMMA in the human body after TJR implantation. The study
involved comparing selected mechanical parameters of both samples prepared according to the
manufacturer’s instructions and samples prepared with the addition of GC with grain sizes of 0.4-12
μm and 20-50 μm. Although this material can potentially increase the mechanical strength of PMMA,
serious contamination with GC can lead to PMMA polymerization impairment due to the thermal
properties of GC and, consequently, affect the mechanical properties of PMMA. GC was added in the
following w/w concentrations: 1, 2, 3, 5, 8 and 10%. Results revealed a significant decrease in the
compression strength of PMMA following the addition of 20-50 μm GC, which resulted from the
disturbances in standard polymerization process conditions (time and temperature). Interestingly, the
addition of 0.4-12 μm GC did not affect significantly the compressive strength of the material in the
tested range of concentration.
|
