Table 3.

Association between child’s oral cleanliness and school performance and between toothache during the previous 12 months and school performance (Chi square test)

	Under-achieving	Fair	Good	Excellent	p-values
Substantial plaque. Children aged 6–7 years
Yes (n = 233)	23 (9.8%)	35 (15.0%)	109 (46.8%)	66 (28.3%)	p = 0.032*
No (n = 244)	24 (9.8%)	20 (8.2%)	106 (43.4%)	94 (38.5%)
Missing data (n = 62)
Children aged 10–11 years
Yes (n = 152)	10 (6.6%)	22 (14.5%)	82 (54.0%)	38 (25.0%)	p = 0.002**
No (n = 239)	10 (4.2%)	18 (7.5%)	110 (46.0%)	101 (42.3%)
Missing data (n = 54)
Reported toothache during the previous 12 months. Children aged 6–7 years
Yes (n = 215)	19 (8.8%)	34 (15.8%)	97 (45.1%)	65 (30.2%)	p = 0.089
No (n = 220)	23 (10.5%)	18 (8.2%)	101 (45.9%)	78 (35.5%)
Missing data (n = 104)
Children aged 10–11 years
Yes (n = 155)	4 (2.6%)	18 (11.6%)	90 (58.1%)	43 (27.4%)	p = 0.042*
No (n = 154)	7 (4.6%)	14 (9.1%)	69 (44.8%)	64 (41.6%)
Missing data (n = 136)

*p < 0.05; **p < 0.005