Table 1.

Frequency distribution of self-ligating and conventional subjects' characteristics.

	Total		Self-ligating		Conventional		P value (chi-square test)
	%	(n)	%	(n)	%	(n)
Total	100	150	50	75	50	75
Baseline IOTN-DHC
No or little need	100	6	50	3	50	3	0.783
Borderline need	100	22	54	12	46	10
Need	100	122	53	65	47	57
Sex
Female	100	92	52	48	48	44	0.564
Male	100	58	50	29	50	29
Baseline IOTN-AC (normative)
No or little need	100	4	50	2	50	2	0.689
Borderline need	100	20	55	11	45	9
Need	100	126	56	70	44	56
Age (y)
13–15	100	48	46	22	54	26	0.826
16–18	100	102	51	52	49	50
Social-economic class
(high)	100	134	56	75	44	59	0.346
(low)	100	12	42	5	58	7

IOTN: index of orthodontic treatment need; DHC: dental health component; AC: aesthetic component.