Groups N Mean (SD) P-value Tukey's post hoc
pairwise comparison
of hardness
Group Significancea
Control 10 30.45 (0.96) 0.00;
df = 3 		PTFE 0.00
Ti 0.00
Zn 0.00
PTFE 10 33.43 (0.92) Ti 0.01
Zn 0.00
Ti 10 32.48 (0.97) Zn 0.00
Zn 10 28.6 (0.99) -

aSignificant at the level P < 0.05 (Tuckey's post hoc test).
N = number; SD = standard deviation; PTFE = polytetrafuoroethylene.