Background: Dentin hypersensitivity (DH) is a painful condition associated with challenging treatment options.

Aims: This study aimed to evaluate the effectiveness of a diode laser (976 nm) for occluding dentinal tubules in vitro and to compare the effectiveness of this laser with that of the conventional chemical agent sodium fluoride gel in occluding the Dentinal Tubules.

Materials and Methods: Ten extracted human premolars were utilized in the current in vitro experimental scanning electron microscopic (SEM) study. Using a diamond saw with coronal dentin from each tooth specimen, dentin disks 1.0 mm in thickness were cut perpendicularly to the long axis of each tooth. Ten dentin disks were prepared, and each specimen was divided into four equal parts, pretreated with ethylenediaminetetraacetic acid (17%), and subsequently divided into four groups: (Group 1) the control group, (Group 2) the 976 nm diode laser with a power of 1 watt, (Group 3) the sodium fluoride only group and (Group 4) the combined laser and sodium fluoridearnish group. The samples were analysed using a scanning electron microscope at different magnifications (100 µm, 50 µm, 20 µm, and 2 µm). ANOVA was used to compare the differences in dentinal tube diameter among the four groups, with the level of significance set at a P value ˂0.05.

Results: Group 1 (control, no treatment) had all the dentinal tubules opened. Both the laser group and the sodium fluoride group demonstrated partial occlusion and narrowing of most of the dentinal tubules, while the combined group showed total occlusion of almost all of the dentinal tubules. There was a statistically significant difference between the four groups regarding the diameter of the dentinal tubules.