Table 1.

Descriptive Data and Independent Sample t-Tests From Objective, and Subjective Analysis of Invisalign and Fixed Groups at T₀, T₁, and T₂ ^a,b

	Invisalign Group (n = 24)				Fixed Group (n = 20)				P Value
	Min	Max	Mean	SD	Min	Max	Mean	SD
Upper boundary frequency (MHz)
T0	10.72	12.73	11.68	0.46	10.37	12.38	11.55	0.55	.42
T1	10.37	12.21	11.36	0.50	10.37	12.12	11.44	0.55	.64
T2	10.55	12.3	11.53	0.48	10.37	12.3	11.45	0.56	.62
Patient perception of speech alteration (mm)
T1	4.67	86.67	43.83	18.84	6.0	68.33	30.78	21.16	.04*
T2	6.0	66.0	36.14	16.42	0	32.00	21.52	11.89	<.01**

^aMax indicates maximum; min, minimum; SD, standard deviation.

^bSpeech alteration of all patients at T₀ was used as baseline and therefore assumed to be 0.

^*Significant by the Student's t-test at P < .05.

^**Significant by the Student's t-test at P < .01.