Table 2.

Prevalence of dental caries and gingival bleeding according to socio-demographic background and oral-health related behaviours

Variables (N = 482)	DMFT > 0 (%)	p-value	Gingival bleeding (%)	p-value
Socio-demographic background
Sex		< 0.001*		0.791
Boy (233)	27		88
Girl (249)	42		89
Father’s education level		0.345		0.003*
Primary school level, ≤ 6 years (271)	33		92
Secondary school level or above, > 6 years (211)	37		83
Mother’s education level		0.361		< 0.001*
Primary school level, ≤ 6 years (282)	33		93
Secondary school level or above, > 6 years (200)	37		82
Monthly pocket money		0.120		< 0.001*
Less than 50RMB (~ US$ 7) (325)	32		94
More than 50RMB (~ US$ 7) (157)	39		77
Oral health-related behaviours
Toothbrushing frequency (daily)		0.667		< 0.001*
Less than twice (315)	34		93
Twice or above (167)	36		80
Sugary snacking habits		0.142		0.129
No (335)	33		90
Yes (147)	40		85
Sour food snacking habits		0.298		0.057
No (360)	33		90
Yes (122)	39		84

*Statistically significant difference between groups

DMFT decayed, missing and filled teeth, RMB Renminbi (Chinese Yuen), US$ U.S. Dollar