• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.3
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• pp.220-230
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• 1995

In this report, a case is presented in which resected mandible was reconstructed immediately with vascularized bone graft and adjunctive implantation of osseointegrated dental implants. The primary was central odontogenic myxoma of mandible extending from symphysis to the left condylar neck. The hemimandibulectomy defect was restored with free fibular flap. Three months after 1st surgery, the transplant received five $IMZ^{(R)}$ implants. The masticatory function was restored with the implant borne denture. The result including facial appearance was very satisfactory.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.2
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• pp.122-129
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• 1994

This study was undertaken to determine whether the addition of calcium sulfate to toothash material (Toothash : plaster of paris=2 : 1) would improve its stabilizing property without adversely affecting its osteoconduction. The radiographic and histologic examinations of bone response of this composite material was performed after 1-, 3-, 5-, 8-, and 12-week implantation in calvaria of rats. No sign of extensive inflammatory response was detected. No movement could be observed with this composite material. Creeping substitution was observed in the surgical site. The direct union between toothash and growing bone after 12 weeks of implantation was observed in the defect margin. We could observe this composite implant material is resorbing slowly as time is over.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.3
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• pp.253-263
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• 1995

Microsurgical vascularized bone transfer has the disadvantages of limitation of available donor sites, loss of donor function, and the possibility of donor site defects or deformity. To overcome these shortage of current microsurgical tissue transfer, the method of creating the neovascularized free flap has been introduced. Potentially, this technique must be an innovation in providing the free vascularized bone grafts that are not limited by natural vascular anatomy. But, as could be imagined technique resulted in unavoidable donor bone defect and additional operation for harvesting the autologous bone. The purpose of this study was to evaluate the efficacy of demineralized allogeneic bone as a possible substitute for autologous bone in fabricating the neo-osseous flap. By histologic, microangiographic and radioisotope method, the viability and vascularity of neo-osseous flap, which has been fabricated using allogeneic bone or autologous bone, was assessed in rat model. After 6 weeks, demineralized allogeneic bone showed consistent bone formation and neovascularization. The clinical and microscopic findings of demineralized allogeneic bone group were inferior to those of autogenous bone with regard to bone regeneration. The amount of bone blood floow per dry weight of demineralized allogeneic bone group was significantly higher than that of autogenous bone, even higher that of control intact iliac bone. In conclusion, findings supported that allogeneic bone could be the potential substitute for autologous bone source in creating a prefabricated neo-osseous flap.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.167-172
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• 2009

The maxilla rarely undergoes necrosis due to its rich vascularity. Maxillary necrosis can occur due to bacterial infections such as osteomyelitis. viral infections such as herpes zoster and fungal infections such as mucormycosis, aspergillosis etc. Herpes zoster is a common viral infection, the oral soft tissue manifestations of which are widely known and recognized. Extremely rare complications such as osteonecrosis, and secondary osteomyelitis in maxilla were observed. But, reports of spontaneous tooth exfoliation and jaw osteonecrosis following herpes zoster infection in the distribution of the trigeminal nerve are extremely rare in the literature. We report a case of maxillary necrosis by herpes zoster in an uncontrolled diabetic patient. There was extensive necrosis of the buccal and palatal mucoperiosteum and exposure of the alveolar bone. This patient was successfully treated using a removal of necrotic bone and nasolabial flap. We briefly discuss different diseases which can lead to maxillary necrosis and a review. Analysis of the pathogenesis of herpes zoster and bone necrosis are discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.7.1-7.5
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• 2018

Background: Oroantral communicating defects, characterized by a connection between the maxillary sinus and the oral cavity, are often induced by tooth extraction, removal of cysts and benign tumors, and resection of malignant tumors. The surgical defect may develop into an oroantral fistula, with resultant patient discomfort and chronic maxillary sinusitis. Small defects may close spontaneously; however, large oroantral defects generally require reconstruction. These large defects can be reconstructed with skin grafts and vascularized free flaps with or without bone graft. However, such surgical techniques are complex and technically difficult. A buccal fat pad is an effective, reliable, and straightforward material for reconstruction. Case presentation: This report describes three cases of reconstruction of large oroantral defects, all of which were covered by a pedicled buccal fat pad. Follow-up photography and radiologic imaging showed successful closure of the oroantral defects. Furthermore, there were no operative site complications, and no patient reported postsurgical discomfort. Conclusion: In conclusion, the use of the pedicled buccal fat pad is a reliable, safe, and successful method for the reconstruction of large oroantral defects.

• Archives of Plastic Surgery
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• v.46 no.5
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• pp.480-483
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• 2019

Repairing surgical defects of the nose is still challenging due to its tridimensional shape and its aesthetic concern. Difficulty in reconstructing nasal subunits lies in their contour, skin texture and limited availability of adjacent skin. For lower nasal dorsum and supra-tip regions, we design a new combined local flap as existing local flaps may give disappointing results. This combination flap was performed on two patients for reconstruction of the lower nasal dorsum area after basal cell carcinoma excision. Size of the excision ranged from 20 to 25 mm diameter and safe margins were obtained. The defects were reconstructed with a local flap that combined a rotation nasal flank flap and a V-Y advancement nasolabial flap. Excision and reconstruction were performed in a one-stage surgery under intravenous sedation and local anesthesia. There were no postoperative complications and no flap loss occurred. Aesthetic and functional results after 6 months postoperatively were satisfying without modification of nasal shape. This flap is reliable and offers interesting functional and aesthetic outcomes. It can be considered as a new reconstruction alternative for supra-tip and lower nasal dorsum skin defects performed in a one-stage procedure under local anesthesia.

• Archives of Craniofacial Surgery
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• v.20 no.3
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• pp.203-206
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• 2019

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroectodermal carcinoma arising from mechanoreceptor Merkel cells. Multiple MCCs are even rarer. We report a case of two independent MCCs simultaneously present in the cheek of a patient, which were effectively and esthetically treated using a cheek flap. Punch biopsy performed in a 60-year-old woman admitted with a chief complaint of two skin-colored hard nodules in her left cheek, accompanied by an itching sensation, was suggestive of MCC. Accordingly, we performed sentinel lymph node biopsy through the modified Blair incision under general anesthesia, in cooperation with the head and neck surgery department. The defect was covered with a cheek flap by slightly extending the existing incision following wide excision with a safety margin of 1 cm. This paper is significant in that it introduces an effective reconstruction technique that maintains function using a cheek flap for the management of this rare case. In addition, this paper is the first to classify multiple MCCs according to the time of onset. We believe that this paper presents an effective alternative reconstruction technique with sentinel node biopsy through the modified Blair incision.

• Korean Journal of Metals and Materials
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• v.46 no.3
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• pp.144-149
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• 2008

Equal channel angular pressing (ECAP) has been studied intensively over the decade as a typical top-down process to produce ultrafine/nano structured materials. ECAP has successfully been applied for a processing method of severe plastic deformation to achieve grain refinement of magnesium and to enhance its low ductility. However, difficult-to-work materials such as magnesium and titanium alloys were susceptible to shear localization during ECAP, leading to surface cracking. The front pressure, developed by Australian researchers, can impose hydrostatic pressure and increase the strain level in the material, preventing the surface defect on workpiece. In the present study, we investigated the deformation and fracture behavior of pure magnesium using experimental and numerical methods. The finite element method with different ductile fracture models was employed to simulate plastic deformation and fracture behavior of the workpiece.

• Archives of Craniofacial Surgery
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• v.21 no.6
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• pp.384-386
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• 2020

This report describes osteotomy and iliac bone graft for malunion caused by failed mandibular fracture reduction. A 27-year-old man was referred 3 months after a motor vehicle accident. At another hospital, two operations had been performed for symphyseal fracture using two resorbable plates. Malocclusion was noted, and panoramic radiography and computed tomography revealed a misaligned dental arch, with a 9.37-mm gap between the central and the lateral incisor of the left mandible. A wafer was made from the patient's dental model, and a maxillary arch bar was applied. Through a lower gingivolabial incision, osteotomy was performed between the malunited symphyseal fracture segments. Both segments were reduced to their original position using the wafer and fixed with titanium miniplates via intermaxillary fixation (IMF). The intersegmental gap was filled with cancellous bone from the iliac crest. The gingival defect was covered with a mucosal transposition flap from the gingivolabial sulcus. IMF and the wafer were maintained for 5 and 9 weeks, respectively. At postoperative week 13, the screws were removed from the mandible and satisfactory occlusion was noted. His mouth opening improved from 2.5 to 3 finger breadths (40 mm). This case demonstrates the need for sufficient IMF when using resorbable plates.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.12-20
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• 2022

Delamination and burr defects are important problems in drilling fiber reinforced plastics. A method for measuring FRP drilling defects has been studied. Delamination and burr factors were defined as the relative length or area. Using these factors, the effects of tool shape and drilling conditions on delamination and burr were studied. In this study, the defects that occur when drilling a glass-carbon fiber hybrid composite were compared in terms of three factors. In the glass-carbon fiber hybrid composite, the effects of the feed rate and tool point angle on the delamination and burr factors were similar to those in previous studies. The diameter of the tool did not affect the defect factor. A circular burr was generated in a drill tool with a point angle of 184°, and a relatively small deburring factor was observed compared with a tool with a point angle of 140°.