Influence of needle size at a given preparation size Influence of preparation size at a given needle diameter 25/06 40/04 25 G 30 G Group Δ 25 G to 30 G Δ 25 G to 30 G Δ 25/06 to 40/04 Δ 25/06 to 40/04 1 (0-5°); n=10 2.7 mm (CI: 2.09-3.41) 1.7 mm (CI: 0.79-2.51) 1.8 mm (CI: 0.9-2.7) 0.8 mm (CI: 0.00-1.40) 2 (6-15°); n=32 2.9 mm (CI: 2.35-3.31) 2.5 mm (CI: 2.10-2.93) 1.6 mm (CI: 1.04-2.1) 1.2 mm (CI: 0.83-1.64) 3 (16-25°); n=37 2.7 mm (CI: 2.27-3.02) 2.9 mm (CI: 2.50-3.47) 1.2 mm (CI: 0.74-1.48) 1.4 mm (CI: 1.1-1.8) 4 (>25°); n=21 2.1 mm (CI: 1.72-2.47) 2.7 mm (CI: 2.09-3.29) 1.3 mm (CI: 0.93-1.64) 1.9 mm (CI: 1.24-2.52) Mean 2.63 2.61 1.41 1.38

Table 1: Differences (Δ) in millimetres with CIs, reflecting the influences of preparation size and irrigation cannula diameter on the apical part of the WL not reached by the irrigation cannula.