Table 1. Relative optical density (ROD) of artificial enamel lesions treated with rGO/AG, GO and AgNPs at different depths of tooth specimens (n=10).

Caries depth	Negative Control	0.08 mg/mL rGO/Ag	0.12 mg/mL rGO/Ag	0.16 mg/mL rGO/Ag	0.16 mg/mL rGO	0.16 mg/mL AgNPs	10 ppm NaF
10 μm	74.44±3.35c	76.58±3.30bc	77.06±1.66bc	76.93±3.47bc	79.73±6.16b	79.69±7.54b	94.64±3.87a
30 μm	72.89±2.73c	74.80±3.49bc	75.43±2.90bc	74.81±3.85bc	76.33±3.41b	76.87±3.98b	97.99±2.34a
50 μm	73.53±2.28c	74.32±2.81c	75.59±3.18bc	77.47±5.08b	75.46±3.54bc	75.86±3.68bc	98.84±2.26a
70 μm	73.92±2.04c	75.33±3.29bc	76.94±4.74bc	78.30±5.17b	75.71±3.24bc	76.40±4.51bc	99.60±0.79a
90 μm	75.35±3.49c	75.51±3.65c	78.76±6.18bc	82.04±6.19b	75.61±3.62c	80.59±5.65b	99.50±0.85a
110 μm	75.51±3.71d	77.11±3.85d	82.41±3.85c	93.40±3.86b	75.57±3.78d	83.69±3.63c	99.89±0.55a
130 μm	76.31±4.45c	75.59±3.84d	83.50±3.47b	99.20±1.20a	75.79±3.84c	86.42±5.01b	99.91±0.37a
150 μm	78.82±4.07b	84.48±3.61bc	85.90±3.26c	99.64±0.64a	77.07±3.58b	94.37±5.08ac	99.98±0.21a
170 μm	86.18±9.82b	90.73±7.46bc	95.20±5.97cd	99.81±0.39ac	81.40±10.78b	99.82±0.33ac	100.00±0.20ad
190 μm	90.20±8.55b	97.91±2.38bc	98.85±1.35c	99.87±0.28ac	86.37±11.08b	100.00±0.06ac	99.95±0.20ac
210 μm	92.55±8.94b	99.51±0.66bcd	99.87±0.31ac	99.98±0.12ac	90.81±9.64bc	100.00±0.09ad	99.98±0.14ac
230 μm	96.25±5.08a	100.00±0.06bc	100.00±0.07bc	99.89±0.25ac	97.47±2.30ac	100.00±0.07bc	99.90±0.25ac

ROD was calculated as ODR=ODl/ODs × 100%; ODl represents the OD of the enamel demineralized layer, ODs represents the OD of the sound enamel tissue (blank control) measured at the corresponding tooth specimen level. Values annotated with different superscripts (a–d) within the same row indicate statistically significant differences (p<0.05) between different groups