The Usefulness of Piezoelectric Surgery in Sagittal Split Ramus Osteotomy.

Mandibular osteotomy carries with it a risk of damaging blood vessels and nerves when using traditional surgical techniques. Piezosurgery®, is a new technique that uses ultrasonic vibration to enable bone-selective sectioning without damage to the surrounding soft tissues. However, paralysis may not be completely eliminated using Piezosurgery® for osteotomy. We investigated how piezoelectric surgery in bilateral sagittal splitting ramus osteotomy (BSSRO) affected the surrounding soft tissue. Forty-four patients with skeletal mandibular prognathism underwent mandibular setback with BSSRO. Patients were divided into two groups, those treated by the conventional chisel technique and those treated by Piezosurgery®. Osteotomy time, blood loss, and incidence of paresthesia were compared retrospectively. Osteotomy time and blood loss in the piezo group were significantly reduced compared to the chisel group. Interestingly, whereas paresthesia incidence immediately after the operation did not differ between the groups, paresthesia in the piezo group 3 months postoperatively was significantly less than in the chisel group. However, a few cases of paralysis did not recover even in the piezo group. Blood loss and osteotomy time did not correlate with the paralysis. This study demonstrates that while piezoelectric surgery does impact the nerve tissue, the use of piezoelectric surgery in BSSRO leads to significantly less long term paralysis compared to surgery done by chisel.

Three-dimensional ultrastructural analysis of the interface between an implanted demineralised dentin matrix and the surrounding newly formed bone.

Previous investigators have reported that transplanted demineralised dentin matrix (DDM) influences bone formation in vivo. However, the specific mechanism of how dentinal tubules contribute to bone formation has not been determined with regard to DDM transplantation therapy. In this study, we ultrastructurally investigated how DDM contacted the surrounding newly formed bone using a scanning electron microscopy (SEM) three-dimensional reconstruction method that is based on focused ion beam slicing and SEM (FIB/SEM). A pulverised and processed DDM derived from human teeth was implanted into rat calvarial bone defects, and a series of X-ray computed tomographic images were obtained over 12 weeks. Implants with surrounding new bone were removed and histologically examined using FIB/SEM. After obtaining objective block-face images, the target boundary face was reconstructed three-dimensionally. The osteocytes of the new bone tissue surrounding the DDM formed a network connected by their cellular processes and formed bone tissue. It is also interesting that the cellular processes of the osteocytes extended into the dentinal tubules, and that bone tissue with canaliculi had formed and filled the DDM surface.

Metastatic gastric tube cancer detected in a resected mandibular bone with osteoradionecrosis.

Osteoradionecrosis (ORN) of the jaw is an intractable complication of radiotherapy for head and neck cancer. However, osteolytic lesions are often hard to distinguish from malignancies. We report a rare case of metastatic cancer in a resected mandibular bone after segmental resection for ORN of the jaw. A 63-year-old male with a history of subtotal oesophageal resection for oesophageal cancer and reconstruction of the oesophagus with a gastric tube subsequently developed ORN of the jaw. Conservative treatment was unsuccessful and pathological fracture of the necrotic mandible occurred. The patient underwent segmental resection of the mandible and adenocarcinoma was detected in the resected mandibular bone. Immunohistochemical staining for cytokeratin 7 and 20 revealed that the adenocarcinoma had metastasized from the reconstructed gastric tube. This case highlights the fact that cancers of the gastric tube may metastasize to radiation-induced necrotic bone tissue in the mandible.