During air abrasion, an instrument that works like a mini sandblaster is used to spray away decay.  This procedure is primarily for small conservative cavities and the polisher is aimed at the area of decay.  Small particles of decay on the tooth surface are removed as the stream of particles strikes them. The small particles of decay are then "suctioned" away.  In many cases no injections are required because the decay has not broken completely through the enamel.