Parameter Class Presurgery Postsurgery Difference t- test
Mean ± SD Mean ± SD Mean ± SD Pa Pb
Cephalometry
(hard tissue) 		SNB (°) II 75.5 ± 3.8 77.7 ± 4.2 - 2.2 ± 1.8 < 0.001d 0.939
III 82.1 ± 5.9 79.7 ± 5.3 2.3 ± 2.2 0.003d
ANB (°) II 4.9 ± 3.5 2.5 ± 3.3 2.4 ± 1.5 < 0.001d 0.841
III - 0.1 ± 2.5 2.0 ± 3.3 - 2.2 ± 1.6 < 0.001d
NAPg (°) II - 6.7 ± 8.6 - 3.1 ± 8.2 - 3.6 ± 4.5 0.006d 0.898
III 1.2 ± 6.1 - 2.6 ± 7.4 3.8 ± 3.2 < 0.001d
N-B (mm) II 7.7 ± 3.4 5.9 ± 4.0 1.8 ± 1.7 < 0.001d 0.370
III 1.1 ± 6.3 3.6 ± 5.8 - 2.5 ± 2.8 0.007d
N-Pg (mm) II 6.6 ± 4.8 5.1 ± 5.2 1.5 ± 1.6 0.002d 0.124
III 0.4 ± 7.3 3.3 ± 6.8 - 2.9 ± 3.2 0.006d
ANS-Gn (mm) II 36.4 ± 3.4 37.1 ± 2.7 - 1.1 ± 2.1 0.044c 0.467
III 40.7 ± 4.1 40.1 ± 4.8 0.6 ± 1.8 0.203
Cephalometry
(soft tissue) 		Facial convexity (°) II 163.6 ± 6.3 167.7 ± 6.4 - 4.1 ± 4.2 < 0.001d 0.818
III 173.9 ± 4.8 169.6 ± 6.9 4.3 ± 3.5 < 0.001d
Labiomental angle (°) II 86.6 ± 28.7 109.1 ± 14.4 - 22.3 ± 22.7 < 0.001d 0.051
III 129.7 ± 11.6 124.1 ± 16.7 5.6 ± 13.1 0.143
Lower lip length (mm) II 24.7 ± 2.9 25.6 ± 3.1 - 0.8 ± 2.6 0.201 0.254
III 29.2 ± 2.1 28.7 ± 2.9 0.1 ± 2.1 0.388
Photogrammetry Facial convexity (°) II 166.5 ± 6.1 160.5 ± 4.9 5.9 ± 7.1 0.002d 0.614
III 174.8 ± 5.6 163.8 ± 5.4 10.5 ± 49.5 0.003d
Labiomental angle (°) II 102.2 ± 19.3 112.1 ± 15.8 - 10.1 ± 15.9 0.044c 0.857
III 129.9 ± 16.2 120.6 ± 11.9 10.6 ± 19.3 0.959
Lower lip length (mm) II 24.7 ± 2.9 25.6 ± 3.1 - 0.8 ± 2.6 0.201 0.933
III 29.4 ± 2.7 28.9 ± 2.3 1.7 ± 8.5 0.448

aP refers to pre- and postsurgical differences (t-test).
bP refers to differences in pre- and postsurgical changes between Class II and III patients (t-test).
cSignificant at the level P < 0.05 (two-tailed).
dSignificant at the level P < 0.01 (two-tailed).