Objective: The purpose of this study was to evaluate the abrasiveness of a new air polisher on root surfaces. Method and materials: Fifty extracted human teeth were air polished for 5 seconds. Results: All root surfaces showed a circular defect visible with the naked eye. Scanning electron microscope examination showed smooth crater walls and a few open dentin tubules, but most seemed to be obliterated. Laser profilometry of the exposed areas revealed defects with an average depth of 484 µm, whereas the unexposed root surfaces showed irregularities with an average depth of 323 µm. The depths of the abraded areas were evaluated in relation to the values for the unexposed surfaces, and an average depth of 161 µm was found. The difference between the exposed and unexposed surfaces was statistically significant. Conclusion: The present study indicates that the air polisher has a strong abrading effect on exposed root surfaces and should therefore be used with caution on patients with gingival retractions.