Table 6 Mean color difference (ΔΕ) data

Thoma et al. 2018a [54]

CM: 5.51 ± 1.56/SR: 7.42 ± 5.05 (p > 0.05)

CM: 3.38 ± 0.99/SR:4.06 ± 1.06

N/A

N/A

Buchi et al. 2014 [23]

t: 6.3 ± 2.2/c: 4.6 ± 1.8 (p > 0.05)

t: 1.6 ± 0.4/c: 1.8 ± 0.7 (p > 0.05)

t: 6.2 ± 1.9/c: 4.2 ± 1.6 (p > 0.05)

t: 6.5 ± 4.6/c:4.9 ± 2.1 (p > 0.05)

Thoma et. al 2016b [55]

Abutment vs control tooth: P: 7.55 ± 3.02

W: 7.52 ± 2.29

Crown vs control tooth: P: 6.16 ± 2.48

W: 8.31 ± 3.33

N/A

Crown vs control tooth:

P: 4.50 ± 1.93

W: 9.72 ± 3.82

(p > 0.05)

Crown vs control tooth:

P: 6.88 ± 2.45

W: 8.31 ± 2.98

(p > 0.05)

Jung et al. 2008 [13]

ΔΕ implant: 7.4-7.6 (p > 0.05 between groups)

ΔΕ tooth-implant overall: All-ceramic 3.4 ± 1.4

PFM 5.2 ± 2.3 (p > 0.05)

ΔΕ tooth-implant grafted (p > 0.05)

ΔΕ tooth-implant non-grafted (p = 0.04) (PFM higher)

All-ceramic: 3.4±0.8

PFM: 2.9±0.9 (p>0.05)

N/A

N/A

Bittner et al. 2020 [65]

ΔΕ when change from gray to pink abutment still above clinical threshold

N/A

6M: t:6.2/c:6.14

6M: t: 8.42 /c:7.96

Martinez-Rus et al. 2017 [71]

Soft tissue level: Ti: 11.56 ± 3.4

GTi: 8.96 ± 3.1

PTi: 10.68 ± 4.2

Zr Ti-base 6.06 ± 3.2

Coronal level: Ti: 10.42 ± 6.3

GTi: 9.16 ± 6.5

PTi 8.66 ± 6.1

Zr Ti-base 5.76 ± 2.9

1.63±0.64 mm

N/A

Correlation between ΔΕ and thickness

Ti: p = 0.024

PTi: p = 0.048

N/A

Lops et al. 2017 [70]

Gold: 11.43 ± 4.05

Ti: 13.55 ± 6.91

Zr: 11.37 ± 4.67 (p > 0.05)

*all over clinical threshold ΔΕ 8.47

2.57±0.5 mm

G: 9.82

Ti: 13.86

Zr: 10.86 (p > 0.05)

N/A

Bressan et al. 2011 [22]

G: 8.9 ± 0.4 (SE)

Ti: 11 ± 0.4 (SE) (p < 0.05)

Zr: 8.5 ± 0.4 (SE) *over ΔΕ 3.7

N/A

G: 8.6 ± 1.4 (SE)

Ti: 9.5 ± 1.4 (SE)

Zr: 7.5 ± 1.4 (SE)

G: 9.1 ± 0.8 (SE)

Ti: 11.9 ± 1.2 (SE)

Zr: 8.9 ± 0.7 (SE) (p > 0.05)

Thoma et al. 2017 [72]

ΔΕ abutment test: 8.27 ± 4.03

ΔΕ abutment control: 8.49 ± 3.59

ΔΕ crown test: 8.32 ± 3.57

ΔΕ crown control: 7.61 ± 4.03 (p > 0.05)

N/A

ΔΕ crown c vs ΔΕ crown t:

−2.08±3.82

(p < 0.05)

ΔΕ crown c vs ΔΕ crown t:

0.75 ± 2.30