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Magnetostrictive ultrasonic insert

Also called: Cavitron-type insert, magneto insert, stack insert, ultrasonic insert

A metal-stack insert that vibrates in an oval path; all sides of its tip work.

Ultrasonic scalers shake a thin tip thousands of times a second to break up calculus while water cools it and flushes the area. In a magnetostrictive unit, the insert has a stack of thin metal strips (or a metal rod) that grows and shrinks in a magnetic field, so the tip moves in an elliptical (oval) path and every side of the tip is active. Inserts are often rated 25 kHz or 30 kHz to match the unit.

How to spot it

  • A long insert with a metal strip stack or rod, a rubber O-ring, and a grip, which slides all the way into the handpiece.
  • Magnetostrictive vs. piezo: magnetostrictive inserts are long stacks; piezo tips are small and screw onto the handpiece.

What it is used for

  • Removing calculus and biofilm, with water lavage (flushing) and cavitation (tiny bursts of bubbles that disrupt bacteria).
  • Thin tips at low power go deeper; thicker tips at higher power remove heavy deposits.

Safety and care

  • Critical item (it goes into soft tissue or touches bone): clean it, package it and heat-sterilize it after every patient.
  • It makes aerosols (fine spray); use high-volume evacuation and proper PPE.
  • Check tip wear: a worn tip loses power; about 1 mm of wear cuts efficiency by roughly 25%.
  • Ask the clinician before using it on patients with older unshielded pacemakers or other listed precautions.

Related

Sources: RDH Magazine. The 411 on magneto and piezo ultrasonics, Gehrig JS, Shin DE. Fundamentals of Periodontal Instrumentation and Advanced Root Instrumentation, 9th ed. Jones & Bartlett, 2023 (plus Newman & Carranza's Clinical Periodontology), CDC. Guidelines for Infection Control in Dental Health-Care Settings, 2003. MMWR 2003;52(RR-17), Dentsply Sirona. Cavitron Ultrasonic Inserts, Directions for Use (IFU 79457)