Figure 4. Relationships between wear and mechanical properties. To understand the mechanisms of three-body wear of dental composites, we established linear best-fits between wear depth W_D and (A) hardness H, (B) elastic modulus E, (C) flexural strength S, and (D) fracture toughness K_IC of the nano-silica-fused whisker composites at filler level mass fractions ranging from 0% to 74%. Each value is the mean of 6 measurements, with the error bar showing 1 standard deviation (mean ± SD; n = 6).