Table 3 Univariate and multiple logistic regression analysis for the high DMFT value of the crown

Gender

Male

1

0.79

1

0.42

Female

1.06 (0.70–1.62)

1.26 (0.72–2.20)

Residence

Urban

1

0.1

1

0.78

Rural

0.70 (0.46–1.07)

1.11 (0.54–2.27)

Age

35–44

1

–

1

–

55–64

8.25 (2.82–24.17)

0.69

5.11 (1.67–15.64)

0.81

65–74

51.96 (18.242–147.98)

< 0.0001

31.20 (10.70–90.96)

< 0.0001

Level of education

Low (Illiteracy and primary school)

1

–

1

–

Medium (Middle school)

0.13 (0.03–0.54)

0.96

0.47 (0.06–3.43)

0.31

High (College degree and above)

< 0.001 (< 0.001- > 999.99)

0.95

0.28 (0.09–0.89)

< 0.0001

Level of income

Low (≤ 20,000 RMB)

1

–

1

–

Medium (20,000- < 40,000 RMB)

0.64 (0.34–1.24)

0.85

1.27 (0.56–2.89)

0.66

High (≥ 40,000 RMB)

0.47 (0.28–0.79)

0.06

0.71 (0.36–1.41)

0.33

Frequency of tooth brushing

Low (< once/day)

1

< 0.0001

1

0.006

High (≥ once/day)

0.24 (0.15–0.37)

0.39 (0.21–0.72)

Dental visit experience

Yes

1

0.93

1

0.51

No

1.02 (0.67–1.55)

0.78 (0.42–1.47)

Knowledge and attitude of oral health

Positive

1

0.01

1

0.21

Negative

1.75 (1.14–2.68)

0.72 (0.39–1.33)

Frequency of dessert

Scare

1

–

1

–

< once/day

0.57 (0.35–0.92)

0.08

0.64 (0.32–1.30)

0.45

≥ once/day

0.85 (0.40–1.77)

0.76

2.75 (0.87–8.68)

0.28

Frequency of drink with sugar

Scare

1

–

1

–

< once/day

0.35(0.19–0.64)

0.10

0.56 (0.24–1.29)

0.80

≥ once/day

0.46(0.15–1.39)

0.65

0.40 (0.10–1.58)

0.39