Proliferation of (a) normal human foetal osteoblasts (hFOB 1.19, ATCC CRL-11372) and (b) normal mouse calvarial preosteoblasts (MC3T3-E1 Subclone 4, ATCC CRL-2593) after 4 and 7 days of cell culture on polystyrene (PS, control), Cur_WPI25_HAp, and Cur_WPI35_HAp biomaterials. Cell proliferation was assessed using the WST-8 assay. The normal distribution of data was analyzed using a D’Agostino and Pearson omnibus normality test, then one-way ANOVA test followed by Tukey’s multiple comparison were performed in order to determine statistical differences between samples, p < 0.05: * Significantly different results between Cur_WPI25_HAp or Cur_WPI35_HAp biomaterials and polystyrene (PS) at the same time of experiment; # significantly different results between results obtained after 4 and 7 days of incubation. FI denoted fold increase in cell proliferation.