Table 2: Pretreatment characteristics of the extraction group and the non-extraction group.

Measurements Extraction group(n = 30) Mean ± SD Non-extraction group(n = 30) Mean ± SD Significant difference between extraction and non-extraction groups P Value
Skeletal
SNA (deg) 84.0 ± 3.6 83.9 ± 2.9 0.889
SNB (deg) 79.6 ± 3.4 77.7 ± 3.0 0.02*
ANB (deg) 4.5 ± 2.2 6.3 ± 1.7 0.001**
SN-MP (deg) 32.7 ± 4.6 32.3 ± 6.1 0.758
SNPog (deg) 78.7 ± 3.3 77.9 ± 3.6 0.362
Pog to Y axis (mm) 47.9 ± 9.5 44.5 ± 8.1 0.14
Dental
U1-NA (deg) 33.0 ± 6.5 27.3 ± 7.9 0.003**
U1-NA (mm) 9.2 ± 2.3 5.9 ± 2.6 0.000**
L1-NB (deg) 33.6 ± 5.0 30.5 ± 4.9 0.019*
L1-NB (mm) 8.6 ± 2.4 7.5 ± 1.8 0.041*
Pharyngeal airway
PM-UPW (mm) 19.2 ± 4.7 17.5 ± 4.7 0.172
U-MPW (mm) 10.7 ± 2.2 8.5 ± 2.6 0.001**
PASmin (mm) 11.6 ± 3.5 8.9 ± 2.2 0.001**
V-LPW (mm) 15.9 ± 2.4 14.5 ± 2.8 0.046*
Soft palate
NL/PM-U (deg) 131.9 ± 6.1 132.1 ± 7.0 0.891
PM-U (mm) 32.0 ± 3.0 34.0 ± 3.8 0.029*
SP-T (mm) 8.8 ± 1.2 9.4 ± 1.5 0.130
Tongue position
H-VT (mm) 34.1 ± 3.4 34.7 ± 3.7 0.526
VT (mm) 70.3 ± 5.9 69.0 ± 6.1 0.401
V-CV (mm) 19.4 ± 2.5 17.6 ± 2.7 0.01*
V-FH (mm) 78.1 ± 6.2 80.9 ± 8.3 0.148
Hyoid position
AH-CV (mm) 31.6 ± 2.6 30.7 ± 3.1 0.251
AH-FH (mm) 80.8 ± 6.6 83.2 ± 7.5 0.187

*P ≤ 0.05; **P ≤ 0.01.