Table 4 Comparison of TP_before and TP_after (Mean (SD)) among three single-shade resin composites (OMN, CDO and CTO) in different thicknesses (1.5 and 3 mm) on three background colors (A1, A3 and B1)

TP (Before Aging)

OMN

2.89

(0.33)

^aA

1.45 (0.19)

^aA

<0.001

2.44 (0.73)

^aA

1.35(1.35)

^aA

<0.001

2.52 (0.52)

^abA

1.93 (0.48)

^aB

0.009

0.121

<0.001

CTO

3.13 (0.90)

^aA

1.73 (0.54)

^aA

<0.001

2.89 (1.05)

^aAB

1.41 (0.27)

^aA

<0.001

2.28 (0.39)

^aB

1.76 (0.42)

^aA

0.005

0.049

0.103

CDO

2.91 (0.54)

^aA

1.45 (0.36)

^aA

<0.001

2.57 (0.43)

^aA

1.62 (0.53)

^aA

<0.001

2.88 (0.24)

^bA

1.66 (0.48)

^aA

<0.001

0.102

0.515

P-value**

0.606

0.156

0.367

0.199

0.003

0.363

TP (After Aging)

OMN

2.19 (0.22)

^aA

1.47 (0.16)

^aA

<0.001

1.88 (0.24)

^aB

1.16 (0.17)

^aB

<0.001

2.49

(0.17)

^aC

1.63 (0.11)

^aC

<0.001

<0.001

<0.001

CTO

2.45 (0.30)

^abA

1.62 (0.51)

^aA

<0.001

3.68 (5.61)

^aA

1.53

(0.29)

^aA

0.198

2.70 (0.60)

^abA

1.89 (0.48)

^aA

0.001

0.626

0.122

CDO

2.50 (0.40)

^bA

1.83 (0.48)

^aA

0.001

2.99 (0.70)

^aB

1.67 (0.82)

^aA

<0.001

2.92 (0.24)

^bAB

1.88 (0.18)

^aA

<0.001

0.039

0.609

P-value**

0.039

0.128

0.404

0.053

0.032

0.069