SummaryAir‐powder abrasive systems are used in dentistry to remove dental plaque, calculus and stain from the surfaces of teeth. A model system consisting of a thin layer (14 μm) of vacuum‐deposited aluminium was used to demonstrate the effectiveness of such a system. Photomicrographic analysis showed two distinct areas of removal: an inner area where removal of aluminium was complete, surrounded by an area where removal was incomplete.With the aid of a relocation pin attached to the nozzle of the instrument it was demonstrated that nozzle–target distance, the air pressure input, the flow of water and the time of operation were all factors which affected the clinical efficiency of the inst