Table 5.

Variation differences between different landmarks*

Measurement	Non-extraction	Extraction
	P-value	P-value
NLF1L–NLF2L	0.355	0.011ƚ
NLF1R–NLF2R	0.636	0.982ǂ
NLF1L–NLF1R	0.802ǂ	0.844
NLF2L–NLF2R	0.982	0.942
NLF3L–NLF3R	0.415	0.581
L′–L′′	0.995	1.000ǂ
R′–R′′	0.516	0.103
L′–R′	0.499	0.877
L′′–R′′	0.990	0.882ǂ
ChL–ChR	0.933	0.596
ULP–LLP	0.432	0.000ƚ
Ls–Li	0.068	0.057
CphL–CphR	0.248	0.800
CkL–CkR	0.904	0.604
BuL–BuR	0.455	0.701
A′–B′	0.777	0.946ǂ

^ƚSignificant difference between the different landmarks, P < 0.05; ^*The data conformed to normal distribution and variances uniform, and a paired samples t-test was used; ^ǂThe data did not conform to a normal distribution and uniform variances, therefore a Wilcoxon signed-rank test was employed