Bracket system Mean force (N)* [standard deviation]
0° Angulation 7° Angulation
0.014 wire 0.018 x 0.025 0.018 x 0.025
Self ligating ceramic 2.28a [0.7] 2.92c [0.5] 6.5f [0.1]
Metal slot ceramic 1.76a [0.4] 2.55c [1.1] 8.0g [0.2]
Conventional ceramic 4.34b [0.4] 4.68e [0.6] 9.2h [0.3]
Conventional metal 1.74a [0.4] 3.63d [0.3] 7.7i [0.1]

*Means with the same superscript are not significantly different (P > 0.05) using ANOVA and Tukey's multiple comparisons (N = 50).