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2 Acta of Bioengineering and Biomechanics

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Time and mixing technique-dependent changes in bone cement SmartSet HV

Lelovics H., Liptakova T.

Acta of Bioengineering and Biomechanics

2010

Vol. 12, no. 4

63-67

For the past fifty years bone cements based on polymethylmethacrylate (PMMA) have been used in orthopaedic surgery for fixation of endoprostheses, especially in the cases of total hip replacement. It was shown that during this period vacuum mixing minimalizes the number of unwanted pores and thereby influences the mechanical properties of the cement. It was also discovered that later polymerization of the cement after its implantation lasts up to 6 months and changes its mechanical properties. In this study, mechanical properties (microhardness and elastic modulus measured by microindentation) of hand- and vacuum-mixed acrylic bone cement SmartSet HVŽ were investigated and compared after different time of cement exposition. This study points out that the measures of changes occurring with time in mechanical properties of differently mixed cement samples are equal but microhardness and elastic modulus are different and depend upon the technology of mixing.

Variations of temperature of acrylic bone cements prepared by hand and vacuum mixing during their polymerization

Liptáková T., Lelovics H., Nečas L.

Acta of Bioengineering and Biomechanics

2009

Vol. 11, nr 3

47-51

The aim of this work was to investigate variations of temperature in acrylic bone cement SmartSet HV during its polymerization as the function of mixing technique (hand mixing and vacuum mixing) and sample thickness. The temperature of 25-mm diameter samples differing in their thickness was monitored using a parallel plate measuring system of the compact rheometer preheated to the body temperature. The curves representing the temperature measured and average values of times needed to obtain the peak temperatures of the test samples prepared by different techniques of mixing are presented and discussed. It was found that the maximum temperature and also the times of peak temperatures rose with sample thickness but at different rate for each technique of mixing.