Figure 2. Influence of Poly(P) on calcification and decalcification with in vitro analysis. MC 3T3-E1 cells were cultured with 1 mM Poly(P)75 or 1 mM NaPO₄ for 25 days and stained by the von Kossa method. Arrow represents nodule formation (A). After co-culture of mouse calvarial osteoblasts and bone marrow macrophages, a pit formation assay in the cultivation with the dentin slice was performed. Dentin decalcified by osteoclasts was stained by Mayer’s hematoxylin (B) and counted microscopically (C). Bar: 5 µm. Error bars represent the mean ± SD of three independent analyses.