Acrylic formulations containing bioactive and biodegradable fillers to be used as bone cements: Properties and biocompatibility assessment

The solid phase of bioactive self-curing acrylic cements was modified by different biodegradable fillers such as poly(3-hydroxybutyrate) (PHB) and its copolymer with hydroxyvalerate (PHBV). The addition of the biodegradable fillers made the cement partially degradable, which is important to allow new bone replacement and ingrowth. The thermal analysis, crystallinity, curing parameters, mechanical properties, degradation and cellular tests were studied in order to characterize the cement performance. Within this context it was verified that the incorporation of the PHBV polymer made the cement more resistant, reaching values within the range reported for typical PMMA bone cements. The results also showed that the cement filled with PHBV took up more water than the cement with PHB after 60 days, for all studied formulations. Regarding the osteoblastic cytocompatibility assessment, the inclusion of the PHBV greatly improved the biological response in both cements filled with the silicate or the borate glass, compared to the inclusion of the PHB. The importance of this novel approach resides on the combination of the properties of the cements components and the possibility of allowing bone regeneration, improving the interfaces with both the prosthesis and the bone, and leading to a new material with suitable performance for application as bone cement.