Air polishing units typically generate a stream of pressurized air, carrying specially graded particles of a mild soluble abrasive, such as sodium bicarbonate. The abrasive is directed, in the presence of a stream of water, at a tooth surface to be cleaned. The mixture of water and powderladed stream occurs on the tooth surface and forms a “slurry” that is responsible for the cleaning action.
More recent technology produces a slurry by introducing the water stream into the powder-laden air stream, within the spray head at a critical moment, to produce a fully homogeneous stream that is emitted from a single nozzle. This stream technology configuration has not only been shown to prevent nozzle clogging by preventing the buildup of deposits, but also results in a much more efficient cleaning action because the slurry is formed prior to emission.
Air polishing devices were originally designed to be standalone tabletop units. They have been considered to be the equipment of choice for the hygiene department, sometimes being combined with ultrasonic scaler. They offer a large powder chamber holding enough powder for multiple treatments, along with the convenience of a lightweight, fully autoclavable handpiece design. They are activated by a dedicated foot control that can select either a polishing or rinse mode and they require connections to water, air and electrical outlets. As such, they are normally allocated to a particular treatment room.
Three safety concerns regarding use of the dental air polisher appear in the dental literature including that of the patient, the operator, and others in the treatment room. Patient concerns include systemic problems from absorption of the sodium bicarbonate polishing powder, respiratory difficulties from inhaling aerosols that contain oral microorganisms, stinging of the lips from the concentrated spray, and eye problems from the spray entering the patient’s eyes, especially if contact lenses are worn. Some of these problems could be addressed by coating a patient’s lips with a protective lubricant, using the appropriate technique, removing contact lenses, wearing safety glasses, and placing a protective drape over the patient’s nose and eyes.
Effects of air polishing on gold foil, gold castings, porcelain, amalgam, and glass ionomers have been studied. Air polishing of amalgam alloys and other metal restorations has produced a variety of effects, including matte finishes, surface roughness, morphological changes, and structural alterations. One study found no detrimental changes to the marginal integrity of amalgams. Surface roughness, staining, pitting, and loss of marginal integrity were seen on porcelain surfaces.