Is air polishing safe for enamel and dentine?

Air polishing safety differs between enamel and dentine, and depends heavily on the powder used. For dentine and cementum, glycine powder causes significantly less hard tissue modification than sodium bicarbonate or calcium carbonate powders, and may be safely applied to root surfaces ^[1]. Erythritol powder on exposed root dentine produces a slight but statistically significant increase in average surface roughness, which subsequent polishing with a cup and paste does not reduce ^[2]. In terms of substance loss, air polishing with low-abrasive powders (glycine or erythritol) results in a mean loss of around 8.65 µm, and substance loss per second is highest with air polishing devices compared to ultrasonic scalers, even when using these gentler powders ^[3]. Most studies report higher substance loss with hand curettes than with ultrasonic scalers, placing air polishing in an intermediate position depending on the metric used ^[3]. The indexed literature does not contain passages specifically addressing air polishing effects on intact enamel surfaces, so a direct safety statement for enamel cannot be drawn from this evidence base. Overall, the available evidence suggests that low-abrasive powders such as glycine represent a safer choice for hard tissues than conventional sodium bicarbonate or calcium carbonate powders, but some degree of surface alteration on dentine should still be anticipated ^[1][2].