[Ultrasonic bone cutting in oral surgery: a review of 60 cases]

Surgical reconstruction of bony defects in the oral cavity can often be challenging since thin and fragile bony structures are especially prone to fracture cased by bulky cutting tips or the application of significant pressure by conventional mechanical instruments. The risk of accidental damage to adjacent soft tissue structures, such as nerves, by a dental drill or saw is also extremely high. The use of modulated ultrasound (piezosurgery) makes it possible to overcome such complications as a result of the precise and minimally invasive surgery technique which is limited to mineralized hard tissue.

In 60 patients (38 male, 22 female) a piezosurgery device was used for different bone augmentation procedures before dental implant placement. The instrument uses modulated ultrasound (25 - 30 kHz) and the amplitude of the working tip ranges from 60 mum to 200 mum. The device was employed for sinus floor elevation (25), alveolar ridge augmentation using an autogenous block graft (25), alveolar ridge splitting (5) or lateralization of the alveolar nerve (5). Physiological sodium chloride was used as a cooling solution. For all osteotomies mode boosted burst c and pump 5 were used.

Piezoelectric osteotomy permitted micrometric selective cutting and a clear surgical site due to the cavitation effect created by the cooling solution and the oscillating tip. No excessive bleeding was encountered. The risk of accidental soft tissue harm, such as perforating the sinus membrane or damaging adjacent nerves, was definitely lower than in the case of a conventional bur. No serious complications were encountered in the postoperative wound healing process after 2, 14, 30 and 90 days. However, the surgical procedures were time-consuming.

Piezosurgery is an advantageous osteotomy technique for delicate structures in the oral and maxillofacial region. With respect to osteotomies of thin and fragile bones, the application of ultrasound is superior to other mechanical instruments because of the extremely precise and virtually arbitrary cut geometries, easy handling, efficient bone ablation and minimal accidental damage to adjacent soft tissue structures.