Dentin hypersensitivity is a short, severe pain with fast onset. Therapy aims to either prevent or decrease neural transmission or physically occlude the dentinal tubules. This study aimed to evaluate the effectiveness of commercial desensitizing dentifrice by means of an ex vivo method. Samples (n=8 lower human premolars for each group) were randomly allocated into: G1- brushing with Colgate®Sensitive Pro-Relief; G2- brushing with Sensodyne®Rapid Relief; G3- brushing with Sensodyne®Repair and Protect; and G4- brushing with Colgate®Maximum Cavity Protection. The test bodies were submitted to simulated toothbrushing and dentifrices were analyzed regarding their hydrodynamic size, polydispersity index (PI) and zeta potential. Specimens were evaluated using: scanning electron microscopy (SEM); spectroscopy energy dispersive X-ray (EDS); and profilometry. A qualitative analysis of the photomicrographs and topographies was performed. The dentifrices showed statistical similar physical and chemical characteristics. They also demonstrated obliteration of dentinal tubules when micrographs were observed. Regarding the chemical elements present in the dentin samples, there was a statistically significant difference between the control and experimental surfaces in the four groups. Joint data analysis shows that the desensitizing dentifrice showed better results with regards to the obliteration of dentinal tubules compared to positive and negative controls.