CHAPTER 25 PIEZOSURGERY RELATED TO IMPLANT RECONSTRUCTION
Piezoelectric bone surgery is a new osteotomy and osteoplastic technique created by the author to overcome the precision and safety limitations of traditional instruments. This technique is based on the use of microvibrations generated by an ultrasonic device developed with the scientific-technological collaboration of Mectron Medical Technologies (Mectron s.p.a., Carasco, Italy). This new technology was applied for the first time in 1999 for veterinary orthopedic surgery.1
In 2000 experimentation began on human patients and the first pilot study was published introducing Piezoelectric bone surgery to the international scientific community.2 In 2001 production and distribution of the technology began. At the same time intense educational activity began on an international level, which resulted in dissemination of the technology to thousands of professionals worldwide.3–15
Mectron Piezosurgery (Figure 25-1) cuts the bone using the mechanical microvibrations generated by multifrequency ultrasonic vibrations. The mechanical linear microvibrations range from 20-80 microns and the difference between 20 (low) and 80 (high) depends on the efficiency of inserts. Adjusting the variable frequency enables optimization of the ultrasonic cut, thus eliminating dispersion of energy in the form of heat.
The over-modulation of the ultrasonic wave generated by Mectron Piezosurgery (US Patent 6,695,047B2) has the dual effect of cutting the bone and at the same time eliminating bone fragments produced; if the bone fragments remain inside the osteotomy they act as soft and elastic tissue, preventing additional cutting action and resulting in dispersion of kinetic energy as heat.
Microprecision depends on the mechanical cutting action generated by microvibrations invisible to the naked eye. This process makes it possible to reduce pressure on the handle from 2 kg-500 g, thereby ensuring maximum control when working in the proximity of delicate anatomical segments (e.g., the alveolar nerve) and throughout the surgery.
Selective cutting capabilities are enabled by the diamond-coated insert and the type of ultrasonic vibration used, which is less than 30 KHz. This selectivity allows Mectron Piezosurgery to perform osteotomy and osteoplastic techniques without cutting soft tissues. Indeed, any accidental contact with soft tissues only results in stopping heat. Clinical studies demonstrate the extremely high degree of safety of Mectron Piezosurgery when used near nerves such as the alveolar nerve and infraorbital nerve.16
When the saline solution of Mectron Piezosurgery meets the insert, which vibrates at ultrasonic speed, cavitation occurs. Cold vapor bubbles form inside and a shock wave is produced by inertia that blocks blood from flowing out of the capillaries, both by a physical effect and by a biological denaturation process, which in turn activates instantaneous coagulation processes. This phenomenon ensures maximum surgical visibility even in situations in which the anatomical segments are not clearly visible (for instance, deep in an alveor during apex extraction).
Several histological studies conducted in vitro and on animals have demonstrated that the ultrasonic microvibrations generated by Mectron Piezosurgery reduce cutting trauma to a minimum. As a result, bone healing is much faster from both a histological and histochemical standpoint.14 Biomolecular studies comparing implant sites prepared with Mectron Piezosurgery and with a twist drill have demonstrated increased regeneration of bone tissues treated with Mectron Piezosurgery, with an increase of up to 18 times of BMP 4 (bone morphogenetic protein 4) and up to 19 times of transforming growth factor β (TGF-β).17
The clinical benefit is extremely clear immediately after the operation. Already on the day after the operation even soft tissues surrounding the operation site show a rosy color and reduced or absent postoperative edema. Considerable benefits also have been found in relation to patient symptoms, both in terms of increased comfort and better operation preparation, and in terms of faster postopertive recovery.
Mectron Piezosurgery inserts are classified based on features and morphology. Feature classifications include sharp, smoothing, and blunt. Sharp instruments are characterized by the highest degree of cutting efficiency, whereas smoothing instruments are used to perform cuts near sensitive anatomical structures.
The new Piezoelectric bone surgery technique developed by the author is based on the cutting characteristics of Piezosurgery described in the preceding sections. Its application enabled the development of several pioneer techniques for oral, periodontal, and implant surgery. The basic idea was to simplify existing techniques so that a higher number of clinicians could perform them with accurate predictability. This path of clinical scientific development was managed according to the following specific guidelines.
Scientific clinical research has always stemmed from the need to solve a clinical problem. This is why many in vitro laboratory tests on animal bone have been performed to develop instruments and define their effectiveness and efficiency. Scientific-histological research was carried out on animals to assess bone and soft tissue response. Multicenter clinical studies were carried out to establish a clinical protocol for each operation. Every technique is characterized by a protocol divided into subsequent phases indicating the purpose, type of insert, and potential application. This extensive work made it possible to streamline and simplify the following techniques:
The main objective of the extraction technique is to remove the root and preserve the integrity of the alveolar walls and the architecture of periodontal soft tissue. The characteristics of ultrasonic cutting produced by Mectron Piezosurgery, in particular cutting selectivity and micropressure, make it possible to achieve these goals of preservation of morphology and tissue conservation.
Mectron Piezosurgery for extraction surgery (Figure 25-2) is recommended in cases with particular anatomical difficulty such as cases with an ankylotic root or thin, scalloped periodontal biotype. With Mectron Piezosurgery surgical aggression during extraction is focused only on the root surface.
Figure 25-2. A, Canine root fracture. B, Root fraction of the ankylotic canine using Mectron Piezosurgery OT1 insert. C, Root fraction maneuver. D, Performed root fraction. E, The ankylotic apic of the root. F, The root extraction with preservation of the thin buccal cortical bone.
A surgical protocol has been developed for every anatomical condition, which enables the precise internal and external root movement needed for extraction. The primary extraction techniques applicable with Mectron Piezosurgery are root resection, which enables recovery of root movement in the alveolar space while protecting the walls against extraction stress (especially in cases of thin periodontium); Piezoelectric osteoplastic surgery, which consists of consuming the root surface (particularly the ankylotic), protecting the alveolar bone against overheating and improving healing; and extraction of the third molar, where use of Mectron Piezosurgery is particularly beneficial, thanks to improved operation visibility and control over cutting action.