Improvements are provided for a dental air abrasive system of the type which utilizes a compressed gas or air which creates a gas stream. Abrasive particles are introduced into the gas stream and expelled out through one end of a nozzle whereupon the abrasive laden gas stream impinges upon the target, i.e. tooth amalgam, composites, stain and/or tooth dental filling materials. The improvements include the use of two or more hoppers each containing different sized abrasive particles, which are selectively fed, either together or independently of each other, into the gas stream. Different sized abrasive particles are provided in each hopper for cutting different types of tooth structures. Other improvements include the use of fluorescent and/or colored abrasive particles to facilitate the aiming process, a laser beam, strobe, white light or other illuminating sources for aiming the abrasive stream and/or illuminating the target area as well as a disposable nozzle for hygienic reasons. Other improvements include the use of a vacuum evacuation system to minimize dusting of the abrasive particles, as well as a dam removably positioned within the patient's mouth which reflects the abrasive particles back towards the evacuation system. Still other improvements include the use of a microvalve adjacent the nozzle which, when closed, terminates gas flow through the fluid passageway in order to further minimize dusting of the abrasive particles.