The bone surgery has always used manual and rotary instruments. The biomedical engineering with ultrasound working principle has given a new surgery instruments, which allow a selective cutting action of bone tissue and the protection of soft tissue. Our case shows an uncommon clinical lesion surgically dangerous for the narrow adjoining of important anatomical structures as the lower alveolar artery and the lower alveolar nerve. The clinical result and recovery time go toward a smaller traumatic situation of this methodology of the cutting of bone tissue.