An experimental approach to the study of the rheology behaviour of synthetic bone calcium phosphate cements

Calcium phosphate cements were developed to fit surgical needs in biomedical fields such as odontology or traumatology. Nowadays, a broad field of new applications have been found for this kind of materials. Drug delivery systems, tissue-engineering scaffolds and osteoporotic bone filling applications are some of the new fields that are being benefited with these materials. Looking at both, commercial and new experimental calcium phosphate cements it is found that cr-tricalcium phosphate is the main reactive powder responsible for the setting and the hardening of the cement. Thus, it is important to know how alpha -tricalcium phosphate affects injectability of these cements. The aim of this study was to investigate the theological behaviour of alpha -tricalcium phosphate slurries in order to know how the cement injectability should be modified. Factors such as liquid to powder ratio, particle size of the main reactive powder and the addition of dispersants have been considered. The results showed that viscosity decreased when particle size of reactant was increased and when liquid to powder ratio was increased. It was also found that a minimum of viscosity exists at an optimum value of the weight percentage of dispersant.