ULTRASONIC SURGERY: A BRIEF INTRODUCTION
Ultrasonic Surgery (Also known as Piezosurgery) technology has been used in periodontology and implantology for over 2 decades. Piezosurgery is a relatively new technique for osteotomy and osteoplasty that utilizes ultrasonic vibration. Probably, all dentists have used an ultrasonic scaler at some point in their careers to facilitate the removal of plaque and calculus from root structure.
How does it work?
The ultrasonic (or ultrasound) frequency, as the name implies, is a frequency above the audible range for humans, usually above 20 kHz. In dental applications, the frequencies used range from 24 kHz to 36 kHz, the frequency range capable of cutting mineralized tissue. An ultrasonic surgery device is essentially an ultrasound machine with modulated frequency and a controlled tip vibration range. By taking advantage of its settings and tips gives precise bone shaving, rasping, cutting and also can be used as a drill while preserving the surrounding soft tissues.
With piezoelectric ultrasonics, the frequency is created by driving an electric current from a generator over piezoceramic rings, which leads to their deformation. The resulting movement from the deformation of the rings sets up a vibration in a transducer and/or amplifier, which creates the ultrasound output. These waves are transmitted to a handpiece tip, also called an insert, where the longitudinal movement results in the cutting of osseous tissue by the microscopic shattering of the bone. A typical ultrasonic surgery unit is similar to an implant drilling system with a control panel, irrigant, and a handpiece with wire/tubing.
The Clinical Applications
Piezoelectric units provide clinicians with the ability to cut the mineralized tissue selectively. The units’ low kHz frequency allows the soft tissue to “move” with the vibrating insert, thus preventing incision or damage to soft tissue. With higher ultrasonic frequencies, this tandem movement does not occur, resulting in the incision or other damage to soft tissue.4 This “selective cutting action” is very desirable in bone surgery. For example, with piezoelectric bone surgery, a lateral sinus window access can be created without cutting the Schneiderian membrane.
Another characteristic of Piezosurgery units is the micro-vibration of the inserts. These micro-vibrations allow clinicians to make precise and narrow bone incisions, with cuts as small as 0.5 mm to 0.7 mm. The surgeon also benefits from good tactile sensation. Bone saws and dental drills do not have this level of control, precision, and tactile sensation because greater force often is needed with many rotary instruments, and/or there is a partial or complete loss of control of some parts of the cutting surface at any given time. This loss of control can result in damage to underlying structures, especially soft tissue, such as nerves and the sinus membrane in dentistry and other tissues in medical surgery. The micro-vibrations and selective cutting action, therefore, result in greater patient safety.4