Does the bracket–ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial

Figures & data

Figure 1. Standardized activation of nickel–titanium closing spring to approximately twice the resting length (12 mm)

Figure 2. CONSORT diagram showing the flow of participants through the trial

Table 1. Baseline characteristics of the three groups of patients.

		Conventional brackets and elastomerics (n = 13)	Conventional brackets and Super Slick® elastomerics (n = 13)	Self-ligating brackets (n = 14)
Age at start of treatment (years)	Mean (SD)	14·1	13·7	13·9
Gender	Male/female	7∶6	3∶10	7∶7
Incisor Relationship	Class I	4	7	4
	Class II division 1	5	5	7
	Class II division 2	3	1	3
	Class II Intermediate	0	0	0
	Class III	1	0	0
Overjet (mm)	Mean (SD)	3·9	3·9	3·8

Table 2. Descriptive statistics for the standardized amount of space closure in 3 months (mm).

Method		Conventional brackets and elastomerics (n = 13)	Conventional brackets and Super Slick® elastomerics (n = 13)	Self-ligating brackets (n = 14)
Mean space closure		3·0	3·0	2·7
SD		1·2	1·1	1·2
95% confidence interval	Lower	2·3	2·3	2·1
Upper		3·7	3·6	3·4
Range	Min	0·9	1·7	0·5
Max		4·4	5·4	5·3

Table 3. One-way ANOVA with a dependent variable of standardized amount of space closure over 3 months and independent variable of bracket/ligature combination. The descriptives are for the differences between groups.

	Sum of squares	df	Mean square	F	P
Bracket–ligature ombination	0·902	2	0·451	0·334	0·718
				95% confidence interval
		Mean difference	Std error	Lower	Upper
Conventional — slick		−0·1	0·5	−1·2	1·0
Conventional — SLB		0·3	0·4	−0·8	1·4
Slick — SLB		0·3	0·4	−0·7	1·4