Table 1.
SS-SB Group | DLCC-SB Group | DLCC-TB Group |
---|---|---|
(A) Initial drill: 1.5–2 mm ∅, tip angle 30° and 3 cutting edges; (B) pilot drill: 2 mm ∅, tip angle 120° and 2 cutting edges; (C) progressive drill: 3 mm ∅, 120° tip angle and 4 cutting edges; (D) final drill: 3.3 mm ∅, 120° tip angle and 4 cutting edges(∅: diameter).