Piezoelectric vs. magnetostrictive ultrasonic scaler: What’s the difference?

Dental clinicians know that using ultrasonic instrumentation saves time and reduces clinician muscle fatigue. But if you’re looking for a new ultrasonic scaler, temping, or working in multiple offices, it helps to know the difference between magnetostrictive and piezoelectric ultrasonic scalers.

The question of which one is better is still up for debate, and the research is conflicting. Some studies show that piezos are more efficient and leave a smoother surface,¹ while others found that magnetostrictive devices produced a better outcome.² Others concluded that both ultrasonic scalers produced similar results.^3,4

Likewise, some studies found that patients experienced less discomfort with the piezo,^5,6 while others concluded that more patients preferred the Cavitron.⁷ This perhaps leads to the conclusion that both types of ultrasonic instrumentation are effective and comfortable for patients when utilizing proper technique and tip selection.

What are the main differences between piezoelectric and magnetostrictive devices?

Piezos use electrical energy to activate crystals within the handpiece to produce vibrations of the powered working end. On the other hand, magneto devices, such as the Cavitron, transfer electrical energy to metal stacks or a ferrous rod to produce vibrations of the powered working-end.

Another difference is the amount of water flow needed to prevent overheating. With magneto devices, both the handpiece and working-end should be irrigated with water to prevent overheating the handpiece and working-end.⁸ However, for piezo devices, only the working-end needs to be cooled with water since little heat is generated to the tip.

You might also be interested in: Getting comfortable with the piezoelectric scaler

Additionally, magnetostrictive scalers have an elliptical or circular tip movement with all surfaces of the tip being active. Conversely, piezoelectric devices have a linear movement of the tip, no magnetic field, and only the lateral surfaces of the tip are most active.⁹

What these differences mean for clinicians

The main difference is that when using a piezo, you will primarily need to use the lateral surfaces of the tip, similar to using hand instruments. When using a magneto device, all surfaces of the tip are active, so you have a little more freedom in your technique. As well, you don’t need to turn the water up with the piezo as high as you do with magneto devices, since it will not heat up as easily.

You may also notice that while using a magneto device, calculus deposits tend to break off in chunks, whereas with the piezo the calculus deposits typically disintegrate into small particles. Another small but noticeable difference is that the piezo is adapted at a 0–5-degree angulation compared to the magneto, which is adapted at a 15-degree angulation. A high pitch sound can be heard with the piezo if the adaptation is too open, where you are starting to use the back of the tip rather than the lateral sides.⁹

These differences may seem daunting at first, but there are also many similarities between the two types of ultrasonic scalers. Both come with multiple tip selections and have similar device controls. The learning curve of switching from one device to another is typically not too challenging for clinicians. Which device is better is still up for debate and currently determined by clinician preference. The main takeaway is to understand the difference between magneto and piezo devices to ensure that your technique is correct so you can achieve the best results possible for your patients.

References

1. Yousefimanesh H, Robati M, Kadkhodazadeh M, Molla R. A comparison of magnetostrictive and piezoelectric ultrasonic scaling devices: an in vitro Journal of Periodontal & Implant Science. 2012;42(6):243-247. doi:10.5051/jpis.2012.42.6.243.
2. Busslinger A, Lampe K, Beuchat M, Lehmann B. A comparative in vitro study of a magnetostrictive and a piezoelectric ultrasonic scaling instrument. Journal of Clinical Periodontology. 2002;28(7):642-649. doi:10.1034/j.1600-051x.2001.028007642.x.
3. Singh S, Uppoor A, Nayak D. A comparative evaluation of the efficacy of manual, magnetostrictive and piezoelectric ultrasonic instruments – an in vitro profilometric and SEM study. Journal of Applied Oral Science. 2012;20(1): doi:10.1590/S1678-77572012000100005.
4. Mahiroglu MB, Kahramanoglu E, Ay M, Kuru L, Agrali OB. Comparison of root surface wear and roughness resulted from different ultrasonic scalers and polishing devices applied on human teeth: an in-vitro study. Healthcare. 2020;8(1):55. doi:10.3390/healthcare8010055
5. Muhney KA, Dechow C. Patients’ perception of pain during ultrasonic debridement: a comparison between piezoelectric and magnetostrictive scalers. Journal of Dental Hygiene. 2010;84(4):185-189.
6. Daly S, Newcombe RG, Claydon NCA, Seong J, Davies M, West, N. A randomized controlled trial to determine patient experience of a magnetostrictive stack scaler as compared to a piezoelectric scaler, in supportive periodontal therapy. Journal of Dentistry. 2020;93: doi:10.1016/j.jdent.2020.103279.
7. Ikeda Y, Kawada A, Tanaka D, Ikeda E, Kobayashi H, Iwata T. A comparative questionnaire study of patient complaint levels between magnetostrictive ultrasonic scaler (CavitronÒ) and piezoelectric ultrasonic scalers. International Journal of Dental Hygiene. 2020;19(3):273-278. doi:10.1111/idh.12478.
8. Gehrig JS, Sroda R, Saccuzzo D. Fundamentals of Periodontal Instrumentation & Advanced Root Instrumentation. Enhanced 8^th Jones & Bartlett Learning; 2019:661-667.
9. Tanner K. Cavitron or Piezo. Accessed August 15, 2023. https://www.bisco.com/blogs/cavitron-or-piezo/