Role of ultrasonic cleaning in control of cross-infection in dentistry.

The dye/paper method of mapping ultrasound fields has been used to demonstrate the non-uniform distribution of energy density and cavitational activity in an ultrasonic cleaning bath. It is also shown that removal of a layer of artificial contaminant from a surface proceeds at rates which vary considerably with position because of standing waves set up by reflections in the walls of the bath and at the liquid surface. In view of the use of such baths as part of the process of controlling cross-infection in dentistry, it is suggested that manual cleaning of reusable instruments may be necessary as well.