Groups N Mean (SD) P-value Tukey's post hoc
pairwise comparison
of hardness
Group Significancea
Control 10 21.42 (0.87) 0.00;
df = 3 		PTFE 0.00
Ti 0.00
Zn 0.08
PTFE 10 22.57 (0.81) Ti 0.01
Zn 0.00
Ti 10 24.15 (0.88) Zn 0.00
Zn 10 20.75 (0.98) -

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