Recently tissue engineering concept has been developed and well recognized its usability in reconstructive surgery. In this article basic elements for tissue engineering such as stem cell scaffold and growth factors were described for young scientists in the field of oral surgery. Since 1985 we have fabricated several tissue and organs using tissue engineering concepts, for example, skin, cornea, nerve, cartilage and so on. Among them bone and periodontal tissue regeneration have been thought to be the most important target in dentistry. I will discuss the recent status of tissue engineering research and bone regeneration technique for dental implant. In modern dentistry, implant have become a standard of care for occlusion restoration. For dental implant placement, the presence of sufficient bone volume is the most important prerequisite. However, implant surgeon faces frequently with a large alveolar bone defect due to periodontal disease or other serious injuries. In this circumstances we have attempted to regenerate bone in a significant osseous defect with minimal invasiveness and good plasticity, and to provide a clinical alternative to autogenous bone grafts. The new technology we developed was called as “injectable bone”, and involves the morphogenesis of new tissue using constructs formed from isolated cells with biocompatible scaffolds and growth factors, which are established by the tissue engineering concept. In our previous study, we used mesenchymal stem cells (MSCs) as the isolated cells, and Platelet-rich plasma (PRP) as the growth factors and scaffold for bone regeneration and succeeded a progress bone formation in the grafted area. Based on the series of experimental studies, we applied the injectable bone for alveolar bone augmentation for implant installation.
A rare case of papillary cystadenocarcinoma of the sublingual gland was immunohistochemically studied. Regional lymph node metastasis was present at the time of diagnosis. Histologically, the tumor showed an invasive, cystic growth pattern and had a conspicuous papillary component. The predominant cell type of the tumor was a combination of tall columnar and large cuboidal cells. Immunohistochemical analysis indicated higher labelling indices of CD34 (31.9%) and Ki67 (40.1%) as compared with adenoid cystic carcinoma (ACC). Cyclooxygenase-2 expression was similar to that of ACC. These findings suggested a characteristic high-grade malignancy that required close follow-up.
In 1973, Nezelof et al. reported that the lesion cells in histiocytosis X represented either local or disseminated proliferation of Langerhans' cells. Therefore, the name of this disease has been changed from histiocytosis X to Langerhans' cell histiocytosis (LCH). Recently, we encountered a patient harboring a solitary LCH lesion in the mandible. Approximately 1 year after segmental resection of the mandible, disease recurred in the same region. To treat the recurrent lesion, radiotherapy was employed. In addition, LCH lesions were detected in the 12th thoracic vertebra by bone scintigraphy, radiography, computed tomographic scan, and magnetic resonance imaging. This lesion was orthopedically treated. Thirteen months after treatment, neither recurrence nor emergence of new lesions has been detected.
We treated a patient who had serious visual disturbance (blindness) caused by severe cranial and facial fractures. The patient had right-sided blindness and no response to light before surgery. Eight days after injury, the patient underwent surgery. Continuous or intermittent traction force was applied by means of an elastic band and wire. Immediately after surgery, visual acuity was restored. At about 2 months, visual acuity was 1.0. The traction force method we used is effective for reducing some cranial and facial depressed fractures. In our patient, the optic nerve was decompressed effectively.
Although synovial chondromatosis occurs frequently near the ends of long bones, such as the knee, elbow, and hip joints, it rarely affects the temporomandibular joint. A 52-year-old woman visited our hospital because of swelling in the left side of the temporomandibular joint and trismus. On magnetic resonance imaging, the lesion was found to be chondroid tissue between the left mandibular fossa and the condylar head. Magnetic resonance imaging revealed a high signal mass measuring 35×40mm around the left condylar head. The clinical diagnosis was synovial chondromatosis. Synovectomy and removal of the mass were performed with the patient under general anesthesia. Histopathologically, the mass was formed by typical chondrocytes and was diagnosed to be synovial chondromatosis. The patient has been followed up for 1 year 4 months. There has been no reccurence of the mass or temporomandibular joint disorder.
Garré's osteomyelitis of the jaw is a unique clinicopathologic entity that is characterized by asymptomatic focal osteomyelitis and exuberant periosteal deposition of bone. Odontodysplasia is a rare developmental anomaly of tooth formation in young children. Its causes remain unknown. A 9 -year-old boy presented for evaluation of a painless swelling in the right side of the mandible. The swelling was bone hard and nonfluctutant. Intraoral examination showed partial obliteration of the mucobuccal fold by a bony mass, and the erupted lower right second premolar was malformed. Several kinds of X-ray examinations revealed proliferative periostitis with new bone formation. In addition, the lower right second premolar showed a so-called ghost-like appearance radiographically. Biopsy of the periosteal mass was performed, and the histopathologic diagnosis was reactive bone formation of the periosteum. In this rare case, the periosteal bony reaction in the mandible was successfully treated by tooth extraction with curettage and antibiotic therapy. Osteomyelitis in our patient might have been caused by dental caries of the deciduous lower right second molar. Odontodysplasia resulted from periapical inflammation of the deciduous lower right second molar subsequent to osteomyelitis with periostitis.
Neuroleptic malignant syndrome (NMS) is a rare pathologic condition associated with serious adverse reactions to neuroleptics. We reported a case of gas-producing phlegmon that spread from the floor of the mouth to the cervical region and was accompanied by NMS. A 20-year-old man was referred to us because of painful swelling of the lower left buccal and cervical regions, which caused slight dyspnea. A computed tomographic scan revealed gas accumulation in the oral and cervical fascial spaces. A diagnosis of gas-producing phlegmon spreading from the floor of the mouth to the cervical region was made. After incision and drainage under general anesthesia with endotracheal intubation, the patient remained in intensive care and was given antibiotics and neuroleptic agents intravenously. Gradually, the swelling disappeared, and the endotracheal tube was removed. After extubation, hyperthermia, tremor, tachycardia, hypertension, tachypnea, sialorrhea, and altered consciousness developed. Laboratory results at that time revealed a WBC count of 11, 230/μl and a CK level of 11, 8051U/I, suggesting a diagnosis of NMS caused by haloperidol. He was treated with dantololene (60 mg) and bromocriptine (7.5 mg) and wash-out therapy of myoglobin to avoid acute renal failure. NMS gradually resolved. In severe infections, management of general complications and adverse reactions as well as rapid drainage and appropriate antibiotic therapy is essential.