Ultrasonic scalers are excellent devices for removing stains, hardened calculus, and plaque, compared to compressed-air-driven sonic scalers, which are effective for removing softer deposits.
Ultrasonic scalers use high-frequency vibration and water stream to cleanse gingival tissue and root surfaces. They transmit at 18,000 to 50,000 vibrations per second to a handpiece, compared to 2,500 to 7,000 cycles per second for sonic scalers. Various tips and inserts, such as such as universal, subgingival, and left and right curved, are available for ultrasonic scalers. These tips are better suited for certain procedures and areas of the mouth. Some newer ones use LED technology to offer better visibility.
Because they generate heat, ultrasonic scalers must be connected to an electrical outlet and a water source to cool the instrument and tissues.
The two popular types of ultrasonic scalers are magnetostrictive and piezo. Both offer a variety of inserts and tips, and both are excellent for removing stains and calculus. The choice usually amounts to personal preference.
Clinicians have been using magnetostrictive scalers since the 1960s. They use a pulsating magnetic field that vibrates from 18,000 to 45,000 cycles per second. Tip vibrations are produced by a resonating stack of metal strips or a metal rod attached to the insert.
Professionals who prefer magnetostrictive say that their elliptical or orbital motion is more effective because it generates pathogen-destroying cavitation bubbles 360 degrees around the tip. In contrast, the piezo design creates them only at the two ends of their back-and-forth cycle.
The metal stack in the magnetostrictive scaler generates heat. To prevent overheating, water irrigation must be used. Because the quartz crystal in the piezo scaler doesn't generate much heat, less water irrigation is necessary.
Piezoelectric scalers typically operate at 25,000 to 50,000 cycles per second. In piezo devices, the vibrations are created by oscillations of a quartz crystal in the handpiece. Two sides of the tip are active. There is little or no vibration in the handpiece. Some clinicians prefer the lighter weight and ergonomic design of the piezo scalers and say that their linear oscillation is less likely to abrade the tooth.