To evaluate the efficacy of the Erbium, Chromium-doped Yttrium Scandium Gallium Garnet laser (Er,Cr:YSGG) in sealing dentinal tubules with the incorporation of multi-walled carbon nanotubes (MWCNTs) paste, and without, when used on exposed dentin. Thirty-nine natural posterior teeth were prepared, sectioned, cleaned, and made ready for treatment. Samples were split into 3 groups: Group G1 is the control group (N=10). Group G2 (N=10) was exposed for 2 seconds to a 2780 nm Er,Cr:YSGG laser (Waterlase iPlus, Biolase Technology) in the free-running pulse mode, with 0.25 W power, 20 Hz frequency, a pulse width of 60 μs, a fibre tip size of 600 μm, and non-contact mode, and Group G3 (N=10) was exposed to Er,Cr:YSGG with carbon nanotubes (CNTs) paste along with a pilot research group (N=9). Scanning electron microscopy (SEM) was used to analyze dentinal surfaces. SEM micrographs were obtained after treatment. A qualitative evaluation of the SEM micrographs was conducted to analyze the changes in surface features and calculate the mean difference of tubule occlusion between the groups. The SEM micrographs showed a decrease in the mean diameter of dentinal tubules from 3.13 µm in the control group to 0.733 µm in group G2, whereas group G3 had a diameter of 0.292 µm. The selected parameters of the Er,Cr:YSGG laser (0.25 W/2 s, 70 W/cm²) for groups G2 and G3 were effective in reducing and plugging any exposed dentinal tubules, with the highest effect for group G3 without any sign of fissures or cracks.