Is Deterioration of Surface Properties of Resin Composites Affected by Filler Size?

Table 3

Mean (SD) of 2D roughness parameters.

Group	Tooth-brushing abrasion
	At start (0 cycle)		After 2 years brushing (after 10,000 cycles)		After 4 years brushing (after 20,000 cycles)
	Ra	Rt	Ra	Rt	Ra	Rt
Sp	0.02 (0.01)^a	0.30 (0.04)^a	0.10 (0.01)^a,b	1.30 (0.02)^a	0.90 (0.05)^a	1.90 (0.05)^a
I1	0.03 (0.01)^a	0.31 (0.02)^a	0.30 (0.06)^a	2.27 (0.24)^b	1.30 (0.07)^b	2.94 (0.06)^b
I2	0.03 (0.09)^a	0.35 (0.05)^a	0.70 (0.03)^c	2.28 (0.12)^b,c	1.64 (0.05)^c,f	3.02 (0.14)^b
I3	0.03 (0.01)^a	0.33 (0.02)^a	1.10 (0.08)^d	2.59 (0.07)^c	2.01 (0.07)^d	3.06 (0.06)^b
I4	0.03 (0.01)^a	0.31 (0.04)^a	2.04 (0.15)^e	2.60 (0.21)^c	3.35 (0.31)^e	3.10 (0.12)^b
I5	0.03 (0.01)^a	0.32 (0.03)^a	0.48 (0.12)^a,b,c	2.03 (0.04)^b	1.38 (0.11)^b,c	2.69 (0.06)^c
I6	0.03 (0.01)^a	0.32 (0.03)^a	0.64 (0.04)^c	2.09 (0.02)^b	1.74 (0.08)^f	3.11 (0.06)^b
TC	0.01 (0.01)^a	0.27 (0.02)^a	0.08 (0.02)^a	1.14 (0.04)^a	0.71 (0.04)^g	2.07 (0.08)^a

Within each column, similar superscripts indicate no significant difference (). Within each group, represent significant differences in Ra and Rt among tooth-brushing abrasion cycles.