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Time dependence of the polymerization-shrinkage of bone cements

: Soltész, U.; Schäfer, R.; Kühn, K.-D.; Gopp, U.

17 th European Conference on Biomaterials 2002 : 11-14.9.2002, Barcelona, Spain
Barcelona, 2002
European Conference on Biomaterials <17, 2002, Barcelona>
Fraunhofer IWM ()
Polimerisationsschrumpfung; Knochenzement; Auftriebsmethode; Dichte

Bone cements are usually subject to shrinkage phenomena during their polymerizat ion. Total values of 2 to 5 % in volume are reported in the literature, which is less than the amount of about 20 % in pure MMA on which most bone cements are b ased, but it is still remarkable. This reduction in shrinkage is mainly a conse quence of mixing pre-polymerized beads to the monomer. The main reasons for addi ng pre-polymerized particles are at first a reduction of heat generation in orde r to avoid necrosis of the tissue as far as possible, but secondly, also to prevent too strong volume changes during the setting phase, which possibly could affect the implant/cement or implant/bone interface. Shrinkage data given in the literature are restricted to single values which are determined for a certain time interval during setting. This means that usually not the total shrinkage is measured, but only the portion in the chosen interval. This complicates the compa rison of data, because different methods consider different intervals. Therefore, it should be of great interest to know the full range of shrinkage and its tim e dependence. This would allow not only to compare results of different methods, but also to optimize the time of cement application. In this study an attempt is made to develop a procedure for measuring the mentioned time-dependence.