This work presents the results concerning the damage quantification in human molar dentine surfaces after blasting with sodium bicarbonate. After selection and preparation, the samples were divided into two experimental groups (Control Group and Blasting Group). Initially, the roughness and local hardness (microhardness) of the Control Group were measured and adopted as standard values. In the sequence, the samples of the Blasting Group were subjected to different blasting conditions, making change in parameters as grain size of the sodium bicarbonate particles (60 and 200 mesh), water-sodium bicarbonate-air mixture outflowing (minimum and maximum) and instrumentation time (15 and 30 seconds). Finally, the roughness and the microhardness of the dentine region were measured, as well as the area of the surface depressions due to blasting. The results showed that all blasting conditions caused damages in the dentine region, characterized by an increase in roughness and microhardness, as well as the creation of cavities in this region. The minimum water-sodium bicarbonate-air mixture outflowing was associated with larger values of roughness and microhardness in the dentine region. On the other hand, larger areas of cavities in the same region were created by smaller particles of sodium bicarbonate when blasted with maximum water-sodium bicarbonate-air mixture outflowing.