Piezoelectric ultrasonic scalers rely upon linear movement.
The piezoelectric device uses aligned ceramic
discs to produce the straight micromovements of the tip
through alternating expansion and compression of the
ceramic discs when electricity fl ows over the surfaces of
the crystal (Figure 8). Piezoelectric ultrasonic units operate
at a frequency ranging from 25 to 50 kHz. Given the
linear fashion in which the tip moves, with piezoelectric
devices the tip’s two lateral surfaces are most active. If
adaptation to the tooth’s surface is incorrect the tip will
sound different against the tooth, letting the clinician know that the tip adaptation needs to be altered. Deposit removal should be accomplished by utilizing the lateral surfaces of a piezoelectric insert. Clinicians must develop defi nitive techniques to maximize effi ciency. The tip must be held lateral to the tooth surface, which is often achieved by pivoting the wrist. While clinical results are similar to those obtained with the use of magnetostrictive devices, the limitations of active surfaces afforded by a piezoelectric scaler make it a much more technique-sensitive device. Without successful technique, the clinical outcome of piezoelectric scaling may be compromised – potentially resulting in root surface damage and incomplete deposit removal. In the same vein, clinicians using magnetostrictive units should take care not to limit their instrumentation to the instrument’s lateral surfaces.