a b s t r a c tPurpose: Investigators have hypothesised that piezoelectric surgical device could permanently replace traditional saws in conventional orthognathic surgery. Methods: Twelve consecutive patients who underwent bimaxillary procedures were involved in the study. In six patients the right maxillary and mandible osteotomies were performed using traditional saw, whilst the left osteotomies by piezoosteotomy; in the remaining six patients, the surgical procedures were reversed. Intraoperative blood loss, procedure duration time, incision precision, postoperative swelling and haematoma, and nerve impairment were evaluated to compare the outcomes and costs of these two procedures. Results: Compare to traditional mechanical surgery, piezoosteotomy showed a significant intraoperative blood loss reduction of 25% (p ¼ 0.0367), but the mean surgical procedure duration was longer by 35% (p ¼ 0.0018). Moreover, the use of piezoosteotomy for mandible procedure required more time than for the maxillary surgery (p ¼ 0.0003). There was a lower incidence of postoperative haematoma and swelling following piezoosteotomy, and a statistically significant reduction in postoperative nerve impairment (p ¼ 0.003). Conclusions: We believe that piezoelectric device allows surgeons to achieve better results compared to a traditional surgical saw, especially in terms of intraoperative blood loss, postoperative swelling and nerve impairment. This device represents a less aggressive and safer method to perform invasive surgical procedures such as a Le Fort I osteotomy. However, we recommend the use of traditional saw in mandible surgery because it provides more foreseeable outcomes and well-controlled osteotomy. Further studies are needed to analyse whether piezoosteotomy could prevent relapse and promote bony union in larger advancements. Ó