1. The process by which caries undermines the hard tissues of a tooth causing a cavity to form.
2. The result of passing ultrasonic waves through a solution creating the sequential formation and collapse of vapour bubbles (hydrodynamic turbulence). It can be used to remove contaminating material on the surface of instruments. Cavitation is also produced by the action of ultrasonic scalers when removing hard tooth deposits such as calculus. Cavitation has been used with an irrigant to cleanse the root canal system when undertaking endodontic therapy.