Figure 4 Shannon index (A) and Simpson index (B). These indices were used to estimate microbial diversity between 2 groups. The Shannon index larger, the diversity of the community is higher. In contrast, the Simpson index larger, the diversity of the community is lower. The Shannon index (A) and Simpson index (B) both showed that the species diversity of ZPC group was lower than that of GI and IPR group, and there was a significant difference. * P≤0.05, ** P≤0.01. ZPC – zinc phosphate cement; GI – glass-ionomer; IPR – ICON permeable resin.