Table 5. Surface roughness before and after brushing simulation.

Groups	Food simulating liquids (n = 12)	Mean ± SD
		Before Brushing	After Brushing	P value
VMII (n = 48)	Air	0.246 ± 0.017a	0.254 ± 0.013a	.540
	Distiled water	0.240 ± 0.012a	0.258 ± 0.021a	.308
	0.02 M Citric acid	0.258 ± 0.06a	0.265 ± 0.005a	.121
	75% Ethanol	0.252 ± 0.018a	0.259 ± 0.015a	.092
VE (n = 48)	Air	0.697 ± 0.023d	1.306 ± 0.036k	< .001
	Distiled water	0.684 ± 0.037d	1.134 ± 0.102g	< .001
	0.02 M Citric acid	0.717 ± 0.012d	1.329 ± 0.052k	< .001
	75% Ethanol	0.704 ± 0.018d	1.280 ± 0.093k	< .001
LU (n = 48)	Air	0.517 ± 0.016c	1.156 ± 0.106g	< .001
	Distiled water	0.472 ± 0.023c	1.139 ± 0.75g	< .001
	0.02 M Citric acid	0.541 ± 0.019c	1.164 ± 0.067g	< .001
	75% Ethanol	0.501 ± 0.014c	1.197 ± 0.095g,k	< .001
PMZ (n = 48)	Air	0.633 ± 0.083c,d	1.084 ± 0.039g	< .001
	Distiled water	0.652 ± 0.056d	1.020 ± 0.083f,g	< .001
	0.02 M Citric acid	0.700 ± 0.081d	1.162 ± 0.104g	< .001
	75% Ethanol	0.648 ± 0.046d	1.234 ± 0.069k	< .001

Different superscripted letters indicate statistically significant differences of materials.