Bioactive bone cements containing nano-sized titania particles for use as bone substitutes

Three types of bioactive polymethylmethacrylate (PMMA)-based bone cement containing nano-sized titania (TiO2) particles were prepared, and their mechanical properties and osteoconductivity are evaluated. The three types of bioactive bone cement were T50c, ST50c, and ST60c, which contained 50 wt% TiO2, and 50 and 60 wt% silanized TiO2, respectively. Commercially available PMMA cement (PMMAc) was used as a control. The cements were inserted into rat tibiae and allowed to solidify in situ. After 6 and 12 weeks, tibiae were removed for evaluation of osteoconductivity using scanning electron microscopy (SEM), contact microradiography (CMR), and Giemsa surface staining. SEM revealed that ST60c and ST50c were directly apposed to bone while T50c and PMMAc were not. The osteoconduction of ST60c was significantly better than that of the other cements at each time interval, and the osteoconduction of T50c was no better than that of PMMAc. The compressive strength of ST60c was equivalent to that of PMMAc. These results show that ST60c is a promising material for use as a bone substitute.