Piezosurgery: Ultrasonic Bone Surgery Explained

Piezosurgery is a bone surgery technique that uses ultrasonic vibrations, rather than a rotary bur, to cut bone. The instrument, often called a piezotome, vibrates a tip at very high frequency and with tiny amplitudes: this is a cutting mode quite different from that of conventional rotary instruments. At the practice in Kénitra, piezosurgery is part of the clinical equipment used for certain bone procedures. This article describes what it is, the principle of selective cutting that spares soft tissue, its indications, what the scientific literature actually says, and its limits — drawing on identified medical sources and without any promise of superiority that has not been demonstrated.

The aim is not to present piezosurgery as an instrument that is necessarily better in every situation. It is one tool among others, with certain documented strengths and equally documented constraints, starting with an often longer operating time. Describing a piece of equipment means describing its advantages as well as its limits: that nuance is what makes for honest information.

# What is piezosurgery?

Piezosurgery relies on the piezoelectric effect: certain crystals, when an electric current is applied, deform and generate vibrations. Within the instrument, these vibrations are transmitted to a tip that oscillates at ultrasonic frequency. It is this micrometric movement, and not a rotation, that fragments bone on contact.

According to the review by Agarwal, Masamatti and Kumar published in the Journal of Clinical and Diagnostic Research in 2014, the device produces modulated vibrations in the range of 25 to 29 kHz, with tip amplitudes of roughly 60 to 200 micrometers. This description is useful because it pinpoints what sets piezosurgery apart: cutting through low-amplitude micro-vibrations rather than through the friction of a rotating instrument.

The introduction of this technology into oral surgery is attributed to the work of Tomaso Vercellotti, from 1988 onward, as several reviews recall, including that of Magrin and colleagues (The Open Dentistry Journal, 2015). It is therefore not a recent novelty, but a technique that is now well described in the literature, with several decades of hindsight.

# Selective bone cutting: sparing soft tissue

The central argument for piezosurgery is what is known as selective cutting. At the frequency used, the tip cuts mineralized tissue — that is, bone — effectively, but has far less effect on soft tissue in the event of accidental contact: mucosa, blood vessels, nerves, or the sinus membrane.

The review by Agarwal and colleagues (2014) explains this behavior by the working frequency: ultrasound settings tuned for bone do not have the same cutting effect on soft neurovascular structures. In practical terms, if there is unintended contact with a nerve or a membrane, the risk of severing it is lower than with a rotary instrument. That said, the wording must remain careful: we are talking about a reduced risk in the event of contact, not an impossibility of injuring these structures. Selectivity is an asset, not absolute protection.

This property explains why piezosurgery is often considered near structures that must be respected — for example the inferior alveolar nerve in the mandible, or the membrane lining the maxillary sinus. The clinical equipment and radiological planning, in particular with Cone Beam imaging, remain essential for locating these structures before the procedure: no instrument replaces a prior anatomical assessment.

# What are the indications for piezosurgery?

Piezosurgery is not used for everything. Its place is in situations where the bone cut must be precise and where soft tissue lies close by.

The review by Magrin and colleagues (2015), devoted to piezosurgery in bone augmentation procedures prior to implant placement, describes several applications: sinus floor elevation (sinus lift), harvesting autogenous bone (particles or blocks) from an intraoral donor site, lateralization of the inferior alveolar nerve, and ridge splitting to widen bone that is too thin. Alongside these pre-implant indications are difficult extractions, particularly those of impacted teeth, and more broadly pre-implant surgery.

In practice, the main indications group together as follows:

• sinus augmentation, where the lateral bone window is cut close to the sinus membrane, covered in detail in our article on sinus augmentation, or sinus lift;
• bone harvesting and preparation during a reconstruction, discussed in our article on bone grafting before an implant;
• difficult extractions, in particular the extraction of an impacted wisdom tooth, where bone sometimes has to be worked close to the nerve;
• pre-implant surgery, such as ridge splitting or site preparation.

The choice of technique is decided case by case, after the assessment. Piezosurgery is not automatic: for many procedures, rotary instruments remain perfectly suitable.

# What the literature says: recovery and precision

It is tempting to present piezosurgery as superior in every respect. The literature calls for more restraint: some benefits are documented, but with a variable level of evidence, and with a cost in operating time that comes up in almost every study.

# Wisdom tooth extractions

The meta-analysis by Liu and colleagues, published in the Journal of Dental Sciences in 2018, pooled five randomized controlled trials totaling 402 patients comparing piezosurgery with rotary instruments for third molar extraction. The authors report significantly less pain on day six or seven, less swelling at seven days, and better mouth opening on day one in the piezosurgery group. On the other hand, operating time was significantly longer, by about 6 minutes on average. The authors themselves point out the limitations: trials conducted in a single country, sometimes small sample sizes, and risk of bias in certain studies.

Another analysis, by Cicciù, Stacchi and colleagues (International Journal of Oral and Maxillofacial Surgery, 2021), points in the same direction while remaining cautious. Using trial sequential analysis, it concludes that there is firm evidence that piezosurgery lengthens the duration of the procedure, and only weak evidence that it reduces pain and trismus after extraction. The data were judged insufficient to draw conclusions about nerve complications and swelling. In other words, the benefit for postoperative comfort probably exists, but it is moderate and the level of evidence remains limited.

# Sinus augmentation

For sinus lift, the issue at stake is the sinus membrane, which is thin and easy to perforate. The meta-analysis by Jordi, Mukaddam, Lambrecht and Kühl (International Journal of Implant Dentistry, 2018), covering 69 studies, found an average perforation rate of 8% with the piezoelectric device compared with 24% with rotary instruments, a statistically significant difference. This result is encouraging, but the authors themselves call for caution: most of the included studies were neither randomized nor controlled, detecting perforations was not their primary objective, and some may have been missed. They consider the comparison not fully reliable and call for randomized trials. This figure should therefore be read as a favorable trend, not as a guarantee.

# Implant site preparation

For preparing the implant bed itself, the data are more nuanced. The systematic review by Stacchi and colleagues (International Journal of Oral Implantology, 2020) finds moderate evidence of better secondary implant stability at twelve weeks with piezosurgery, but insufficient data to draw conclusions about marginal bone loss and implant survival; here too, operating time is longer. The meta-analysis by Godoy-Reina and colleagues (Medicina Oral Patología Oral y Cirugía Bucal, 2020) finds no difference in primary stability or in marginal bone loss at medium term, and concludes that survival and bone loss are similar between the two techniques. Piezosurgery therefore does not appear to be a factor in implant success in and of itself.

The full course of implant placement, once the site has been prepared, is described in our article on dental implants in Kénitra.

# What are the limits of piezosurgery?

An honest presentation also means setting out the constraints, which are real and consistently reported in the literature.

The limitation most regularly reported is time. Ultrasonic cutting is slower than rotary cutting, especially in dense cortical bone, as noted by Agarwal and colleagues (2014) and Magrin and colleagues (2015). For the most demanding indications, this extra time may be partly offset by fewer instrument changes, but it remains a real factor to take into account.

It should also be remembered that piezosurgery is a technique, not a guarantee of results. The precision of the instrument does not remove the need for a proper assessment, a correct indication, or adherence to aseptic and healing conditions. Its presence in the clinical equipment describes a means; it does not replace clinical judgment and does not eliminate the risks inherent in any surgery.

# In summary

Piezosurgery is a technique for cutting bone with ultrasound, based on micro-vibrations that cut bone while reducing the risk of injuring soft tissue on contact. Its main indications in oral surgery are sinus augmentation, bone harvesting, difficult extractions and certain pre-implant procedures. The literature suggests a benefit for postoperative recovery after extraction and less membrane perforation during sinus lift, but often with a limited level of evidence, and with a longer operating time. As for the success of the implant itself, results are comparable to those of conventional techniques. It is therefore a useful tool in specific situations, to be chosen after assessment, and not an argument for absolute superiority.