Oral piezoelectric surgery

Piezoelectric surgery is an innovative technique that can be used in the field of oral and dental bone surgery, neurosurgery and vertebral surgery as well as in many other sectors. With this method, surgery to the mandible and maxilla can be carried out more conservatively, with less trauma to the patient and a better post-operative recovery in comparison to traditional surgery using periosteal retractors, scalpels, saws or other instruments. The ultrasounds for piezoelectric surgery have been specifically studied to cut bone while causing  minimum damage to soft tissues. The high frequency ultrasound oscillations between 24,000 and 36,000 Hz, modulated at a low frequency between 10 and 60 Hz, enable efficient and controlled cutting and improve tissue healing.
The continuous irrigation allows the bone to be cut, smoothed and removed, while keeping the temperature low, minimising trauma and maintaining an excellent view of the operating field. Various scientific studies have demonstrated that bone healing is better and faster following piezoelectric surgery than following operations carried out using traditional techniques.
The characteristics of equipment for piezoelectric surgery are:

• micrometric cutting for maximum surgical precision and intra-operative sensitivity;
• selective cutting to minimise damage to soft tissues, thereby maximising safety for both the surgeon and the patient;
• cavitational effect for maximum intra-operative visibility and a blood-free surgical field.

When traditional instruments such as scalpels, bone burs and bone saws come into contact with nerve fibres or blood vessels, they can cause permanent damage; in contrast, piezoelectric instruments do not cause damage to nerve fibres in the case of an occasional, involuntary contact, since they do not cut soft tissues. Furthermore, there is histological evidence of the difference between cuts made by various instruments (Figs. 1a, 1b and 1c – Courtesy of Mectron®) (Videos 1, 2 and 3 – Courtesy of Mectron®) demonstrating the superiority of the piezoelectric cuts.

The piezoelectric technique is indicated for all types of dental surgery: from periodontic to endontic surgery, from implantation procedures to extractions, from orthodontic surgery to reconstructive interventions, and others. In veterinary odontostomatology, the piezoelectric technique is of great use in maxillofacial surgery (Videos 4, 5 and 6), dental extractions (Video 7), bone biopsies (Figs. 2a, 2b, 2c and 2d), etc.

As regards maxillofacial oncological surgery, the piezoelectric technique is slower than the approaches using traditional instruments, but provides great benefits because the cavitational effect renders the surgical field almost bloodless, the cuts are clean and the bone edges can be smoothed effectively. The tips (inserts) for maxillofacial surgery are shown in Figs, 3, 4, 5, 6 and 7.

For dental extractions, particularly for those requiring surgery and for ankylosed teeth, the piezoelectric system enables easy alveolotomy without damaging the soft tissues: furthermore, the flow of physiological saline, necessary for cooling, cleans the surgical field, ensuring excellent visibility. Inserts for dental extractions are shown in Figs. 8, 9, 10, 11 and 12.

Although periodontic interventions are rare in veterinary practice because of the objective difficulty in preserving the results with domiciliary hygiene, when they are carried out, piezoelectric surgery is very delicate, ensuring optimal conservation of the periodontal tissues supporting the teeth.

USE AND CAUTIONS

Before using any new equipment it is important to understand the principles of how it works, its fields of use and its limitations and also to study the user’s instruction manual. These general rules apply to the equipment for piezoelectric surgery; particular attention must be paid to the following points:

• The inserts are very expensive and must, therefore, be stored in specific stands that can be autoclaved (Figs. 13 and 14), if possible divided according to field of use.

• The inserts must be screwed into the hand-piece correctly, using the specific dynamometric torque wrench (Figs. 15 and 16) (Video 8).

• The peristaltic pump used for irrigation of the operating field must be tested before the operation, the bag of physiological saline must be full and the infusion line must be connected to the hand-piece cord.
• The equipment must be set up for the intended procedure (maxillofacial surgery, dental extraction, periodontal intervention, etc.) and for the tissue to be treated.
• Washing: as the saline solution used for cooling evaporates, it leaves crystals within the hand-piece and the internal tubes, impairing the function of the equipment. It is, therefore, important to wash the system two or three times with demineralised water when work with the equipment has been finished (Video 9). The hand-piece and the cord must be washed, dried and placed in a clean, dry place or packaged, together with the hand-piece support, and sterilised in an autoclave.
• When preparing the set, before sterilisation, care should be taken to include all the pieces necessary (Video 10). The hand-pieces used for piezoelectric surgery, like the turbines and micromotors, have sunken parts: class “B” or better autoclaves are required for their correct sterilisation in packages.

Suggested reading

1. Vercellotti T. Technological characteristics and clinical indications of piezoelectic bone surgery. Minerva Stomatologia 2004;53:207-14.
2. Rud J, Andreasen JO, Jensen JE. Radiographic criteria for the assessment of healing after endodontic surgery. Int J Oral Surg 1972;1:195-214.
3. Kim S, Kratchmann S. Modern endodontic surgery concepts and pratice: a review. J Endod 2006;32:601-23.
4. Robiony M, Polini F, Costa F, Vercellotti T, Politi M. Piezoelectric bone cutting in multipiece maxillary osteotomies. J Oral Maxillofacial Surg 2004;62:759-761.
5. Stubinger S, Kuttenberger J, Filippi A, Sader R, Zeilhofer HF. Intraoral piezosurgery: preliminare results of a new technique. J Oral Maxillofac Surg 2005;63:1283-7.
6. Cohen S. Burns RC. Pathways of the pulp, 8ht ed. 2002, Mosby St. Louis.