Table 4 Mean and standard deviation (SD) for different types of ceramic with different surfaces treatment types and immersion type (t-test)

Vita Enamic Glazed

Arabic Qahwa

2.39 (0.33)

2.80 (0.16)

0.40 (0.35)

2.90 (0.192)

Cold Coffee

1.57 (0.55)

2.53 (0.19)

0.96 (0.46)

3.15 (0.82)

P value (t-test)

0.003*

0.008*

0.016*

0.436

Vita Enamic Polished

Arabic Qahwa

1.67 (0.48)

2.18 (0.32)

0.51 (0.31)

2.84 (0.20)

Cold Coffee

1.47 (0.31)

1.98 (0.37)

0.50 (0.20)

3.40 (0.30)

P value (t-test)

0.336

0.244

0.955

0.001*

Vitablocs Mark II Glazed

Arabic Qahwa

1.38 (0.32)

1.76 (0.39)

0.38 (0.29)

2.67 (0.20)

Cold Coffee

1.69 (0.68)

2.01 (0.80)

0.33 (0.33)

2.58 (0.24)

P value (t-test)

0.271

0.430

0.768

0.418

Vitablocs Mark II Polished

Arabic Qahwa

1.81 (0.36)

2.13 (0.61)

0.32 (0.28)

2.73 (0.23)

Cold Coffee

1.33 (0.26)

2.54 (0.50)

1.20 (0.57)

2.62 (0.37)

P value (t-test)

0.010*

0.165

0.002*

0.471

Vita Suprinity Glazed

Arabic Qahwa

2.63 (0.65)

3.30 (0.56)

0.66 (0.42)

1.94 (0.80)

Cold Coffee

2.07 (0.68)

2.37 (0.60)

0.30 (0.22)

1.42 (0.09)

P value (t-test)

0.108

0.007*

0.053

0.111

Vita Suprinity Polished

Arabic Qahwa

1.55 (0.42)

1.90 (0.51)

0.35 (0.19)

2.61 (0.22)

Cold Coffee

1.21 (0.44)

2.20 (0.43)

1.00 (0.20)

1.86 (0.55)

P value (t-test)

0.129

0.217

0.000*

0.003*