Table 2.

Mean ∆E values for each subgroup

Variable	Group & subgroup	Mean ± SD	SE	Median range
	Control I	1.006 ± 0.634	0.204	1.127 (0.154 to 1.989)
∆E	I A	4.316 ± 0.686	0.217	4.328 (3.515 to 5.312)
	I B	6.460 ± 1.872	0.592	5.832 (5.440 to 11.635)
	I C	2.943 ± 0.469	0.148	3.118 (2.198 to 3.476)
	Control II	0.941 ± 0.741	0.199	0.899 (1.174 to 0.963)
	II A	3.004 ± 1.383	0.437	2.902 (0.858 to 5.561)
	II B	4.634 ± 1.969	0.623	5.709 (1.814 to 6.685)
	II C	1.347 ± 0.741	0.234	1.447 (0.134 to 2.063)