A titanium arch bar for maxillomandibular fixation in oral and maxillofacial surgery.
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Equipment Design↗
Biomedical subjects
Ichiro Seto
Publications and source records attributed to Ichiro Seto.
Mandibular reconstruction using a combination graft of rhBMP-2 with bone marrow cells expanded in vitro.
BACKGROUND: The aim of this study was to evaluate the efficacy of a combination graft, using recombinant human bone morphogenetic protein-2 (rhBMP-2) and culture-expanded cells derived from bone marrow, for bone regeneration in a nonhuman primate mandible. METHODS: Five Japanese monkeys were used. Three milliliters of bone marrow was obtained from the tibia and plated into culture flasks. Adherent cells were cultured until near confluence; then, the proliferated cells were transferred to a three-dimensional culture system using collagen beads as the cell carrier. The medium was supplemented with ascorbic acid, beta-glycerophosphate, and dexamethasone to promote osteoblastic differentiation. After further proliferation on beads, the cells were mixed with a collagen sponge that was impregnated with rhBMP-2 and grafted into surgically created segmental bone defects of the mandibles. Three animals received this treatment, and either culture-expanded cells alone or collagen beads without cells were implanted into the remaining two monkeys as controls. The animals were killed 24 weeks after surgery, and the results were assessed by radiographic and histologic evaluation. RESULTS: The combination graft of culture-expanded bone marrow cells with rhBMP-2 in a collagen sponge regenerated the mandibular bone completely. By contrast, the graft of culture-expanded cells alone resulted in only a small amount of bone formation, and the implantation of collagen beads alone led to no bone formation. CONCLUSION: The combination graft of rhBMP-2 and culture-expanded cells, which requires only a small amount of bone marrow, is a reliable method for the reconstruction of segmental bone defects of the mandible.
Animals↗
Reconstruction of orbital floor fracture with polyglactin 910/polydioxanon patch (ethisorb): a retrospective study.
PURPOSE: We sought to evaluate the effectiveness and the complications related to the use of Ethisorb (resorbable alloplastic material) in the reconstruction of orbital floor fractures. PATIENTS AND METHODS: We retrospectively reviewed the charts of all patients who underwent orbital floor fracture reconstruction with Ethisorb since 2001. We only included patients with a minimum follow-up of 3 months. The following data were recorded for every patient: age, gender, cause of trauma, time from trauma to surgery, signs and symptoms, concomitant ocular injuries, radiographic analysis, pertinent intraoperative findings (including the type of approach), follow-up time, and postoperative complications. RESULTS: Eighty-seven patients were included in the study. Twenty-one patients (24.1%) experienced postoperative complications. Of these, only 3 patients (3.4%) had permanent complications directly related to the Ethisorb membrane (diplopia, enophthalmos). Two of these patients required revision surgery and are discussed in the article. CONCLUSIONS: The results of our study demonstrate the effectiveness of Ethisorb in the repair of small-to-moderate orbital floor fracture defects (up to a maximum size of 2 x 2 cm).
Absorbable Implants↗
An alternative soft tissue analysis following mandibular setback by sagittal split ramus osteotomy.
OBJECTIVE: The objective of this study was to determine alternative ratios of soft-to-hard tissue movement after mandibular setback, taking skeletal relapse and differing patterns of facial divergence into account. STUDY DESIGN: Thirty patients were analyzed cephalometrically over a mean follow-up period of 14 months. RESULTS: The relationship between skeletal and soft tissue movements in the mentolabial folds and at the pogonion was 1:1. Final skeletal relapse was 0.8 mm at the B-point and 0.5 mm at the pogonion. Hence, the alternative ratios were 81% and 68%, respectively. The alternative ratio for the mentolabial sulcus was considerably lower in the low- than in the high- and medium-angle groups of patients. However, there was no statistically significant difference between the patient groups with different facial patterns. CONCLUSION: When the smallness of the measured relapse and the tracing error are taken into account, the difference between the alternative and the conventional ratios was insignificant.
Adolescent↗
Oral rehabilitation after mandibular reconstruction using an osteocutaneous fibula free flap with endosseous implants. Factors affecting the functional outcome in patients with oral cancer.
BACKGROUND: The development of endosseous implants and free vascularized bone grafting has permitted increased possibilities of oromandibular reconstruction in patients with oral cancer. In this study, a concept combining surgical and prosthodontic treatments for mandibular fibula free flap reconstruction after tumor surgery was made based on a classification of bone defects. A follow-up study was performed to evaluate the treatment concept for oral rehabilitation in order to identify possible factors which may influence the functional result. MATERIAL AND METHODS: A follow-up examination included 28 patients who underwent the ablative tumor surgery and mandibular reconstruction during a 4-year period. The follow-up protocol included clinical examination, radiological evaluation, and an interview using a standardized questionnaire. The timing of the study was set to allow for a minimum 2-year follow-up (mean 45 months). RESULTS AND CONCLUSION: At the time of examination, prosthesis-based oral rehabilitation was completed in six patients (21%), and the prosthodontic work was still unfinished in four other patients. The other 18 had no dental prosthetic rehabilitation. Thirteen patients received a total of 37 oral implants, and 23 implants were functionally loaded. No implant loss was recorded. Oral functions such as speech, diet tolerance and oral competence were not directly affected by the presence of dentures. A decisive factor affecting the oral function was the extent of soft-tissue loss. According to the classification described here, the extent of the mandibular defect did not correlate with oral functions. The application of oral implants seemed to be advantageous for the oral rehabilitation of patients who had undergone intraoral resections.
Bone Transplantation↗
Bi-directional distraction osteogenesis of the alveolar bone using an extraosseous device.
OBJECTIVES: In alveolar distraction, the bone segment tends to incline palatally or lingually, making rigid control of the segments difficult. The aim of this study was to evaluate the usefulness of a newly developed bi-directional extraosseous alveolar distractor (Medartis V2-Alveolar distractor) for pre- and perioperative vector management. MATERIAL AND METHODS: Seven patients with segmental alveolar atrophy following traumatic tooth loss were treated using the distraction device. The patients were followed up clinically and radiologically. Preoperatively, the initial vector for distraction was determined using CT by measuring the cross-section of the bone. The morphology of the alveolar bone was also analyzed in relation to the planned implant position. Postoperatively, the rate of osteogenesis was monitored with plane radiographs and CT scan. RESULTS: All cases had bone deficit at the anterior surface of the alveolar ridge, showing a typical inclination of the long axis of the bone. Using the distractor, vertical distraction and positioning of the segments with labial orientation was possible. After a consolidation period of 12 weeks on average, sufficient bone formation for implant installation was radiologically observable. Histologic and histomorphometric analysis of one bone biopsy showed very dense mineralized bone (area fraction=78%) with a multidirectional, complex architecture. Implant-supported prosthetic oral rehabilitation was successfully performed in all cases. CONCLUSION: All complications observed in this study were related to the bone deficiency at the anterior surface of the alveolar process. If the technique can be improved, this type of bi-directional distraction is a promising method for alveolar bone repair.
Adult↗
Restoration of occlusal function using osseointegrated implants in the canine mandible reconstructed by rhBMP-2.
Bone morphogenetic proteins have been found to be one of the most promising osteoinductive substances and they are expected to be utilized clinically for the reconstruction of defective mandibles. However, newly formed bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) has not yet been proven able to withstand the masticatory force applied by oral implants. In this study, we examined the qualitative changes in an rhBMP-2-induced mandible from the functional force of osseointegrated oral implants. Segmental (30 mm) bone defects were created in the mandibles of beagles. A poly D,L-lactic coglycolic acid-coated gelatin sponge impregnated with rhBMP-2 was grafted to the resected canine mandible. The new bone was formed 8 weeks after surgery and the Brånemark system fixtures were implanted into the reconstructed mandible. After another 8 weeks, the prosthesis was placed over the oral implants. The prosthesis was maintained in occlusion with the opposing natural dentition for 0, 4, 12, 24, or 48 weeks before the animal was euthanized. The quality of regenerated bone was then evaluated histologically and the osseointegration ratio between oral implants and the bonemeasured. During the first 4 weeks, the ratio remarkably increased from 48.9% to 64.5%. After 48 weeks, the ratio approached about 74.5%. The bone loaded for 48 weeks had undergone extensive remodeling and consolidation; its quality was better and maturer than that of bone that was not loaded. These results indicated that the newly formed bone induced by rhBMP-2 was able to withstand the masticatory force applied by oral implants and had become as functionally mature as a natural bone.
Analysis of Variance↗
[Bone regeneration using bone morphogenetic protein (BMP)].
Bone morphogenetic protein (BMP) is one of the most promising osteoinductive substances and is expected to be applied clinically for bone reconstruction. BMP has restored critical-size bone defects in numerous animal experiments, but the evaluation of bone formation by BMP in primates is a prerequisite for its clinical application. We attempted to restore the mandible bone defects in primates using BMP. The implantation of BMP with the carrier completely regenerated the mandible bone defects in the young primates, and the occlusal function was restored by the dental implants inserted into the regenerated bone. Although the use of BMP alone to regenerate mandible bone defects in old monkeys produced inconclusive results, the combination grafts of BMP and bone marrow, which contained osteoprogenitor cells, were successful. Furthermore, the combination of BMP and the culture-expanded cells derived form bone marrow grafts regenerate the segmental bone defects in the mandibles of old monkeys. Thus, the implantation of BMP with the BMP-responding cells could restore large bone defects even in elderly patients.
English Abstract↗