Table 4. Comparison between individual subgroup among the materials for surface colour.

Study groups	VM	LU	EN	SH	CU	P value$
Stained-water	0.88 (0.34)	1.22 (0.51)	0.89 (0.63)	0.99 (0.46)	1.35 (0.41)	0.353
Stained-acid	1.02 (0.66)	1.23 (0.50)	0.83 (0.49)	1.44 (0.40)	1.2 (0.36)	0.306
Polished-water	1.37 (0.60)	0.80 (0.25)	0.66 (0.16)	0.71 (0.14)	1.25 (0.29)	< .002
Polished-acid	1.29 (0.30)	0.94 (0.67)	0.78 (0.15)	0.73 (0.18)	0.95 (0.25)	0.103
Overall	1.14 (0.475)	1.04 (0.48)	0.79 (0.35)	0.96 (0.295)	1.18 (1.12)	> .01

^§showing effect of material type using ANOVA (P value).

Note: each group shows the degree of influence of toothbrush abrasion on the surface colour.