Table 5.

Estimation of crowding (Irregularity Index) within and between the groups during treatment

Time point	Group 1 Conventional NiTi			Group 2 Cu-NiTi			Group 3 SmartArch®			Severity×wire groupP
	Moderate	Severe	Very severe	Moderate	Severe	Very severe	Moderate	Severe	Very severe	Moderate	Severe	Very severe
T0
n	4	4	5	4	4	5	2	4	7	0.47	0.40	0.49
Mean±SD (mm)	5.5±0.58	7.5±1.0	11.4±2.19	5.75±0.5	8.0±1.15	12±2	6	8.5±1.0	12.15±1.22
Median	5.5	7.0	10.0	6	8	11	6	9	12
P		0.004*			0.007*			0.007*
T1
n	4	4	5	4	4	5	2	4	7	0.57	0.25	0.18
Mean±SD (mm)	2.5±0.58	3.75±0.98	7.2±2.68	1,75±1.26	3.75±1.71	6.4±1.67	2.5±0.71	5.25±1.50	4.71 ±2.49
Median	2.5	3.5	6.0	2	3.5	6	2.5	5	4
P		0.010*			0.021*			0.182
T2
n	4	4	5	3	4	4	2	4	7	0.06	0.67	0.04*
Mean±SD (mm)	0.25±0.58	1,25±1.5	3.2±1.30	1.33±0.58	0.5±1.0	2.25±1.50	0	0.38±0.48	0.71 ±1.25
Median	0.0	1.0	3.0	1	0	3	0	0.25	0
P		0.029*			0.152			0.60
T3
n	1	2	5	3	1	3		2	2	0.56	1.0	0.75
Mean±SD (mm)	0	0	0.4±0.89	0.33±0.58	0	0.67±1.15		0	1 ±1.41
Median	0	0	0	0	0	0		0	1
P		0.741			0.801			0.317
T4
n			1	1		1			1			1.0
Mean±SD (mm)			0	0.5		0			0
Median			0	0.5		0			0
P					0.317
T5
n				1
Mean±SD (mm)				0
Median				0
P
Total Time taken (in weeks)
n	4	4	5	4	4	4	2	4	7	0.47	0.73	0.14
Mean±SD (mm)	9±2	10.0±2.31	12.8±1.79	12±6.53	9.0±2.0	12.0±3.27	6±0	10.0±2.31	9.71±3.15
Median	8	10	12	12	8	12	6	10	8

*Significant difference. Kruskal-Wallis test was performed to assess the relationship between the severity of crowding and the alleviation of crowding, and the relation between the severity of crowding and the time taken for the completion of treatment