Effects of health-promoting school strategy on dental plaque control and preventive behaviors in schoolchildren in high-caries, rural areas of Taiwan: a quasi-experimental design

Table 4 Regression-estimated mean differences of plaque index and plaque control record among schoolchildren by grade between the groups

Variables	IG			CG			Reg. coef.* (95% CI)	ES
	Pre-test	Post-test	Diff	Pre-test	Post-test	Diff
	M ± SD	M ± SD	diff ± SD	M ± SD	M ± SD	diff ± SD
Second grade
PI	1.7 ± 0.5	1.1 ± 0.3	− 0.6 ± 0.5	1.5 ± 0.6	1.2 ± 0.5	− 0.3 ± 0.6	− 0.36 (− 0.59, − 0.13)	0.63
PCR	46.6 ± 18.3	42.2 ± 16.1	− 4.4 ± 23.0	45.5 ± 22.3	68.6 ± 18.1	23.1 ± 24.9	− 27.48 (− 37.16, − 17.80)	1.14
Fourth grade
PI	1.7 ± 0.5	1.2 ± 0.5	− 0.5 ± 0.6	1.5 ± 0.6	1.1 ± 0.4	− 0.5 ± 0.6	− 0.04 (− 0.26, 0.18)	0.07
PCR	43.2 ± 20.8	45.3 ± 16.0	2.1 ± 23.3	41.1 ± 21.1	69.3 ± 18.1	28.2 ± 18.7	− 26.04 (− 33.64, − 18.44)	1.22
Sixth grade
PI	1.5 ± 0.6	1.2 ± 0.5	− 0.3 ± 0.6	1.3 ± 0.5	1.1 ± 0.5	− 0.2 ± 0.5	− 0.11 (− 0.31, 0.09)	0.21
PCR	43.4 ± 22.1	49.1 ± 17.8	5.7 ± 23.5	39.7 ± 18.2	63.7 ± 17.0	24.0 ± 20.2	− 18.38 (− 26.57, − 10.19)	0.85

^*Reg. coef.: Adjusted for gender by linear regression in GEE; Reference: Control group × Time (baseline)
Effect size based on mean difference between groups: Cohen’d, 0.20 is small, 0.50 is moderate, and 0.80 is large

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