Table 4 Estimation of the association between the studied variables and caries prevalence in the 15-year-old group, using bivariate and multivariate logistic regression models

 More than one a day

1^b

1^b

 Once a day

1.64

(1.10–2.44)

0.0153

1.61

(1.03–2.50)

0.0351

 Less than once a day

1.57

(0.54–4.58)

0.4102

1.62

(0.49–5.41)

0.4331

 Occasionally

3.34

(1.05–10.66)

0.0417

3.50

(1.00–12.23)

0.0496

 Never or hardly ever

–

–

–

–

–

–

 Manual

1^b

1^b

 Electric

0.56

(0.33–0.93)

0.0248

0.50

(0.29–0.86)

0.0109

 Both

0.60

(0.38–0.97)

0.0360

0.61

(0.37–0.99)

0.0471

 Toothbrushing starting age

1.10

(1.02–1.21)

0.0140

1.09

(1.00–1.20)

0.0637

 Absence of dental plaque

1^b

1^b

 Plaque on gingival border

1.31

(0.98–1.83)

0.1096

1.39

(0.98–1.98)

0.0643

 Plaque on 1/3 gingival

1.83

(1.16–2.90)

0.0098

1.57

(0.97–2.56)

0.0678

 Plaque on more than 1/3 gingival

1.49

(0.65–3.44)

0.3455

1.19

(0.45–3.15)

0.7251

 Less than 1 month

1^b

1^b

 1–3 months

1.17

(0.77–1.78)

0.4675

1.21

(0.78–1.88)

0.4034

 4–6 months

0.71

(0.46–1.09)

0.1157

0.71

(0.45–1.12)

0.1425

 More than 6 months

0.62

(0.42–0.93)

0.0218

0.60

(0.39–0.93)

0.0232

 Public dental health services

1^b

1^b

 Private dental clinics

1.77

(1.22–2.57)

0.0029

1.77

(1.17–2.66)

0.0068