The mandible is commonly disturbed by medication-related osteonecrosis of the jaws (MRONJ), and preservation of inferior alveolar nerve (IAN) function is critical after surgery. A piezoelectric device is an ultrasound instrument that can remove the bone without soft tissue damage. We evaluated the usefulness of the piezoelectric device for the removal of a sequestrum involving the IAN in MRONJ patients with comparison to a conventional device such as rotary burs. Piezoelectric device group (n=12) and conventional device group (n=8) were compared for age, sex, disease, medication, cause, stage, operation time, hospitalization, prognosis, and subjective neurological dysfunction of the mental region with a question. In the piezoelectric device group, the neurological function was also assessed objectively with neurosensory testing. Both groups were similar in age distributions and MRONJ stage. The piezoelectric device group tended to be associated with female patients with osteoporosis and those receiving oral bisphosphonates; however, no significant differences. A comparison of the clinical outcomes showed a tendency of the reduction in the operation time and hospitalization period in the piezoelectric device group; however, no significant difference. Almost good prognosis was obtained in both groups. Subjective neurosensory dysfunction of the mental region was observed in both groups at 1 week postoperation, but the incident rate was lower in the piezoelectric device group. At 8 weeks postoperation, no patients in the piezoelectric device group showed dysfunction while 2 patients in the conventional device group showed dysfunction. In the piezoelectric device group, objective neurosensory tests of the IAN showed 2 patients of dysfunction at 1 week postoperation, but improved within 4 weeks postoperation. Piezoelectric surgery safely removed the sequestrum adjacent to the IAN with good prognosis in MRONJ patients. Our results indicate that piezoelectric surgery may be helpful in shortening the operation and hospitalization time, and reducing the risk of nerve injury.