Dentin slices were etched with 350 g/L phosphoric acid (Gluma, USA) for 20 s and washed thoroughly with plenty of water for 20 s to avoid excessive drying and to maintain wettability
Energy groups (Er:YAG laser treatment; variable energy; frequency of 10 Hz)
50 mJ group
10
Dentin slices were irradiated using an Er:YAG laser (Fotona, Slovenia) with the R14 handle. The laser was adjusted to the multi-streaming processor (MSP) mode and the optical fiber (diameter 0.6 mm) was applied vertical to the surface of the sample for about 1 mm, followed by irradiation using the mesh scanning mode for 10 s at a frequency of 10 Hz and wavelength of 2940 nm, with 60% water, 40% steam, and variable energy (50 mJ, 100 mJ, 150 mJ, 200 mJ, 250 mJ, and 300 mJ)
100 mJ group
10
150 mJ group
10
200 mJ group
10
250 mJ group
10
300 mJ group
10
Frequency groups (Er:YAG laser treatment; variable frequency; energy of 100 mJ)
5 Hz group
10
Dentin slices were irradiated using the Er:YAG laser with the R14 handle. The laser was adjusted to MSP mode and the optical fiber (diameter 0.6 mm) was applied vertical to the surface of the sample for about 1 mm, followed by irradiation using the mesh scanning mode for 10 s at an energy of 100 mJ and wavelength of 2940 nm, with 60% water, 40% steam, and variable frequencies (5 Hz, 10 Hz, 15 Hz, 20 Hz, 25 Hz, and 30 Hz)
