Table 2.

Mean changes in mm CPD (contact point discrepancy) during the retention period (T1 = post-treatment, to T2 = 1-year follow-up) in retention group and in non-retention group. CI, confidence interval; ITT, intention-to-treat.

		Retention group (n = 32)				Non-retention group (n = 31)
			95% CI				95% CI
		Mean	Lower	Upper	←P→	Mean	Lower	Upper
Change T2 − T1	Little’s index	0.4 mm	0.2	0.6	<0.001	1.3 mm	0.9	1.7
	Arch length	0.0 mm	−0.2	0.2	0.145	−0.3 mm	−0.5	−0.1
	Intercanine width	0.1 mm	−0.1	0.3	0.279	0.4 mm	0.0	0.8
	Intermolar width	−0.1 mm	−0.3	0.1	0.492	0.0 mm	−0.4	0.4
Maximum CPD T1		0.5 mm	0.3	0.7	0.330	0.5 mm	0.3	0.7
Maximum CPD T2		0.7 mm	0.5	0.9	0.002	1.1 mm	0.9	1.3
Maximum derotation T2 − T1		4.7°	3.5	5.9	0.034	6.4°	5.4	7.4

Results (ITT) represented by means and 95% CIs.