Table 2 Prediction of quality of life after orthodontic and surgical treatment from quality of life before treatment, gender, and their interaction

DV = Physical function

0.36

10.36

< .000

 Physical function (before)

0.38

4.46

< .000

0.21, 0.56

 Gender

− 0.75

− 1.44

.15

− 1.80, 0.29

 Interaction

− 0.06

− 0.47

.63

− 0.33, 0.2

DV = Communication

0.36

10.54

< .000

 Communication (before)

0.40

3.67

< .000

0.18, 0.62

 Gender

− 0.26

− 0.66

.51

− 1.07, 0.54

 Interaction

0.09

0.61

.54

− 0.22, 0.41

DV = Pain

0.22

5.19

.003

 Pain (before)

0.46

3.24

.002

0.18, 0.75

 Gender

− 0.15

− 0.87

.39

− 0.50, 0.19

 Interaction

− 0.13

− 0.66

.51

− 0.55, 0.27

DV = Self-concept

0.57

25.04

< .000

 Self-concept (before)

0.62

7.38

< .000

0.45, 0.79

 Gender

− 0.10

− 0.28

.78

− 0.84, 0.64

 Interaction

− 0.08

− 0.52

.60

− 0.39, 0.23

DV = Behaviour

0.54

21.66

< .000

 Behaviour (before)

0.68

7.06

< .000

0.49, 0.88

 Gender

− 0.31

− 1.74

.08

− 0.68, 0.05

 Interaction

− 0.31

− 2.28

.02

− 0.59, − 0.04

DV = Social function

0.44

14.59

< .000

 Social function (before)

0.63

5.89

< .000

0.41, 0.84

 Gender

− 0.32

− 1.79

.08

− 0.69, 0.04

 Interaction

− 0.33

− 2.09

.04

− 0.64, − 0.01