Table 2.

Measurements Performed^a

Variable	Treatment Group (n = 30)		T2–T1	Control Group (n = 30b)		T2–T1	Tx vs Control (P Valued)
	T1	T2	P Valuec	T1	T2	P Valuec	T1	T2
	Mean ± SD	Mean ± SD		Mean ± SD	Mean ± SD
Intercanine width (mm)	22.74 ± 2.15	27.39 ± 2.05	<.001*	24.35 ± 2.04	24.92 ± 2.17	.294	.004*	<.001*
Intermolar width (mm)	30.32 ± 2.80	35.08 ± 3.03	<.001*	30.75 ± 2.20	31.22 ± 2.40	.432	.510	<.001*
Total surface area (mm2)	832.98 ± 88.90	960.03 ± 97.62	<.001*	858.33 ± 70.60	869.19 ± 84.23	.602	.227	<.001*
Surface area anterior halves (mm2)
Crossbite side	103.3 ± 15.74	126.86 ± 21.88	<.001*	107.1 ± 18.77*	107.5 ± 20.05	.937	.400	.001*
Noncrossbite side	103.83 ± 15.85	125.99 ± 20.42	<.001*	110.35 ± 18.80*	109.17 ± 20.42	.822	.152	.003*
Surface area middle halves (mm2)
Crossbite side	131.85 ± 18.43	146.98 ± 17.81*	<.001*	134.83 ± 16.84	135.35 ± 16.59	.907	.517	.013*
Noncrossbite side	129.09 ± 17.22	143.46 ± 17.66*	.002*	135.40 ± 17.8	136.23 ± 16.52	.856	.168	.116
Surface area posterior halves (mm2)
Crossbite side	183.14 ± 21.22	210.31 ± 22.62	<.001*	184.71 ± 16.30	191.26 ± 20.17	.187	.749	.001*
Noncrossbite side	180.67 ± 21.23	205.94 ± 18.38	<.001*	186.78 ± 17.00	189.46 ± 20.74	.598	.224	.003*
Volume (mm3)	3654.25 ± 726.32	4581.80 ± 838.76	<.001*	3922.20 ± 605.20	4082.76 ± 726.42	.372	.126	.019*
Volume anterior halves (mm3)
Crossbite side	299.00 ± 95.00	414.60 ± 117.63	<.001*	326.50 ± 108.27*	343.44 ± 112.44	.566	.300	.023*
Noncrossbite side	298.88 ± 85.55	414.99 ± 124.25	<.001*	337.15 ± 110.41*	344.05 ± 116.11	.819	.139	.030*
Volume middle halves (mm3)
Crossbite side	580.82 ± 154.83	714.23 ± 168.88	.002*	632.44 ± 126.48	648.60 ± 128.03	.634	.163	.102
Noncrossbite side	576.36 ± 130.13	701.84 ± 153.74	.001*	642.06 ± 127.85	651.34 ± 132.44	.789	.053	.188
Volume posterior halves (mm3)
Crossbite side	958.18 ± 210.44	1191.28 ± 237.81	<.001*	983.99 ± 145.01	1047.76 ± 182.81	.154	.583	.013*
Noncrossbite side	940.59 ± 179.54	1154.04 ± 185.99	<.001*	1000.01 ± 146.13	1050.12 ± 192.62	.278	.165	.044*
Molar angulation (°)
Bucco-lingual angle (°)
Crossbite side	12.66 ± 5.77	17.08 ± 6.79*	.009*	12.76 ± 3.77	12.04 ± 4.13	.488	.942	.001*
Noncrossbite side	11.16 ± 4.13	14.01 ± 5.72*	.031*	12.93 ± 4.06	11.76 ± 5.11	.338	.101	.117
Mesio-distal angle (°)
Crossbite side	4.03 ± 4.05	8.40 ± 5.51	.001*	4.31 ± 3.31	2.90 ± 3.13	.096	.766	<.001*
Noncrossbite side	4.43 ± 4.25	8.93 ± 5.46	.001*	4.24 ± 4.06	2.58 ± 3.36	.066	.85	<.001*

^aT1 indicates before expansion; T2, after expansion; Tx, treatment; SD, standard deviation.

^bControl sample had n = 27 at T2 for the surface area and volume measurements and n = 29 for the molar angulation measurements.

^cPaired sample t-test.

^dIndependent t-test.

^*Significant differences, P < .05.