Blasted needle

Drilled needle

Control needle

FP 1st peak

(mean [SD]) (N)

0.42 (0.02)

0.44 (0.05)

0.42 (0.02)

FP 2nd peak

(mean [SD]) (N)

0.82 (0.04) **

0.69 (0.02)

0.73 (0.03)