Table 7 Maxillary premolar movement (Pre-treatment to 24 aligners); Comparison of predicted (virtual) and achieved (actual) tooth movements in all directions. Results of paired T-test or Wilcoxon signed-rank test (N = 18)

Distalization(mm) = + 

Mesialization(mm) = -

-0.08 ± 0.52

(-0.34–0.18)

-0.60 ± 0.49

(-0.84- -0.35)

-0.59 ± 0.59

(-0.88- -0.29)

-0.61 ± 0.58

(-0.90- -0.32)

-0.51 ± 0.54

(-0.78- -0.24)

0.43

0.83

0.73

Extrusion (mm) = + 

Intrusion (mm) = -

0.41 ± 0.45

(0.19–0.63)

-0.29 ± 0.38^#

(-0.48- -0.10)

-0.06 ± 0.40

(-0.26–0.14)

-0.62 ± 0.53^#

(-0.88- -0.35)

-0.47 ± 0.30

(-0.62- -0.32)

0.151

0.80

0.56

Buccal (mm) = + 

Lingual (mm) = -

0.13 ± 0.44

(-0.09–0.35)

0.02 ± 0.43

(-0.20–0.23)

-0.15 ± 0.42

(-0.36–0.06)

-0.24 ± 0.23

(-0.36- -0.13)

-0.28 ± 0.24

(-0.40- -0.16)

0.66

0.32

0.36

Tip (°)

DCT = +

3.90 ± 3.50

3.97 ± 2.71

-1.34 ± 2.64^#

0.15 ± 2.72

0.000^#,*

0.000^*

-5.24 ± 3.47

-3.82 ± 2.77

0.064

6.23

4.67

MCT = -

(2.15–5.64)

(2.62–5.32)

(-2.66- -0.03)

(-1.20–1.50)

(-6.96- -3.51)

(-5.19- -2.44)

Torque (°)

BCT = +

-0.02 ± 2.64

-0.39 ± 2.60

-0.84 ± 2.30

-0.41 ± 2.31

0.32

0.982

-0.82 ± 3.38

-0.02 ± 3.62

0.510

3.39

3.52

LCT = -

(-1.33–1.30)

(-1.68–0.90)

(-1.98–0.31)

(-1.56–0.74)

(-2.50–0.86)

(-1.82–1.78)

Rotation (°)

D-in = +

0.80 ± 4.42

1.32 ± 2.10

0.78 ± 3.43

-0.29 ± 2.24

0.983

0.001^*

-0.02 ± 4.73^#

-1.62 ± 1.74

0.25^#

4.60

2.34

M-in = -

(-1.40–3.00)

(0.28–2.37)

(-0.93–2.48)

(-1.41–0.82)

(-2.38–2.33)

(-2.48- -0.75)