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Repair of long-span mandibular defects with a free fibular flap is now a routine procedure. However, the bone height of the neo-mandible after reconstruction with a fibular flap is about half that of the dentulous mandible. When a fibular graft is placed only at the inferior border of the mandible, the resulting vertical discrepancy between the graft segment and the occlusal plane can adversely affect implant mechanics or denture stability and retention. To overcome these problems, we developed a technique for two-strut type mandibular reconstruction. A vascularized fibular segment is used to reconstruct the inferior basal portion of the neo-mandible, while a non-vascularized residual fibular segment is used to simulate the superior alveolar portion. We used this technique in 22 patients. Graft survival, graft resorption, and the ability to place implants were assessed as compared with those after the conventional one-strut type technique. The fibular segment grafted to the alveolar region was removed in one patient with intraoral wound dehiscence and in two with postoperative infection. All vascularized fibular flaps were successful. The resorption rate was 13.6+/-7.2% for non-vascularized segments and 3.0+/-3.7% for vascularized segments. Dental implants were placed in five of our 22 patients. The crown:fixture length ratio was improved to 1:1.7, as compared with a ratio of 1:1.21 with use of a conventional fibular flap. We conclude that our technique is very easy and safe and provides substantially improved lower-lip and cheek support and implant-prosthetic mechanics than conventional procedures for the repair of long-span mandibular defects.

Statement of Problem: The use of the platelet concentration technique is widespread in dental implant surgery. However, its effect or mechanism is not clearly understood., Purpose: This study introduced an animal model for the platelet concentration technique and evaluated its effect on bone formation with natural cancellous bovine bone mineral., Material and Methods: Adult New Zealand white rabbits were used as the animal model. A density gradient medium was used to obtain a constant platelet count for the preparation of platelet concentrates. In the experimental group, natural cancellous bovine bone mineral with added platelet concentrates was grafted onto critically sized bony defects of the rabbit calvarium. Bone formation in the tissue sections was evaluated with soft x-ray imaging and computer tomography., Results: The average platelet count of the rabbit platelet concentrates was 1487 x 10(3)/microL (287% concentrated). In all the tested parameters, greater bone densities were obtained in grafts that were combined with platelet concentrates., Conclusion: This study showed that the rabbit is a useful animal model for studying the platelet concentration technique. When combined with grafts of natural cancellous bovine bone mineral, the technique increased bone formation.

The purpose of this study was to evaluate the clinical availability of a bisphosphonate in autogenous free bone grafts. Bisphosphonate (0.01 mg/kg/day) was administered daily after an autogenous free bone graft on a rat calvarium. The effects of a bisphosphonate on the resorption of grafted bone and mRNA expression in bone specific genes, i.e. bone morphogenetic protein 2, bone morphogenetic protein 4, alkaline phosphatase, osteocalcin, osteoclast inhibitory factor and calcitonin receptor, were studied via a reverse transcription-polymerase chain reaction (RT-PCR), real time RT-PCR and tartrate-resistant alkaline phosphatase (TRAP) staining. In a clinical and histomorphological review, bone resorption decreased in the experimental group in contrast to the control group where active bone resorption was observed. Bisphosphonate altered not only the mRNA expression of the bone resorption associated genes but also the bone formation associated genes. The expression of the calcitonin receptor (CTR) mRNA was not detected and the osteoclast inhibitory factor (OCIF) was significantly up-regulated in the experimental group as opposed to the control group. The expressions of osteocalcin and alkaline phosphatase mRNAs were also higher in the experimental group. However, there was no significant difference in the mRNA expression of bone morphogenetic proteins between the two groups. The data suggest the possibility of a clinical application of bisphosphonates for decreasing resorption of grafted bone.

Odontogenic keratocyst (OKC) is of particular interest because of its high recurrence rate and aggressive behavior. Two hundred fifty-six cases of OKC were reviewed for the age of the patient at diagnosis, sex of the patient, OKC location, and radiographic findings, and 132 patients with OKC were observed to estimate recurrence, which was analyzed for age, sex, location, and several histopathologic findings. OKCs occurred more frequently in men (58.6%) than in women (41.4%), and they occurred in patients within a wide age range, most commonly in patients in the third decade of life (28.9%), followed by those in the second decade (25.0%); the mean age of patients with OKC was 30.8 years. One hundred ninety-six of the 256 cases (76.5%) occurred in the mandible, and the other 60 cases (23.5%) occurred in the maxilla. The mandibular molar and the premolar areas (51.2%) were the most common sites, and the most frequent clinical manifestations at first admission were swelling, pain, or both (82.4% of total cases). Radiographic impressions included dentigerous cyst (27.3%), OKC (25.4%), primordial cyst (14.8%), ameloblastoma (11.7%), residual cyst (9.8%), and radicular cyst (3.1%). The frequency of recurrence at the follow-up examination was 58.3%. There was no significant difference in the recurrence rate on the basis of the sex of the patient. However, OKCs had a significantly higher recurrence rate in patients in the fifth decade of life than in patients in the other age groups (P = .005).Recurrence rates were significantly dependent on the sites of involvement, and OKCs in the mandibular molar region had significantly higher recurrence rates than those in other sites (P = .001). The histopathologic presence of one or more daughter cysts was significantly related to recurrence (P = .03).

Objective: The coronoid process can be easily harvested as a donor bone by an intraoral approach during orthognathic surgery, especially during mandibular ramus surgery. This study was performed to provide an objective assessment of the coronoid process as a candidate material for paranasal augmentation., Study Design: The dimensions of the coronoid process and the paranasal area were directly measured in 15 dry skulls. Based on these data, the coronoid process was used for a paranasal augmentation in 54 patients., Results: The size and shape of the coronoid process was found suitable for paranasal augmentation; its thickness was 5.4 +/- 0.8 mm on the right and 5.8 +/- 1.2 mm on the left. All patients showed improved facial esthetics without complications when followed up for more than 12 months., Conclusion: The coronoid process seems to be suitable for paranasal augmentation in the dry skull study. Its clinical application is also favorable because its size and morphology fits into the paranasal region, with the additional advantages of biocompatibility, availability, and reduced operation time for harvesting.

Pigmented villonodular synovitis (PVNS) is a benign proliferative disorder of the synovial tissue, that usually affects the knee, ankle and other major joints. Involvement of the temporomandibular joint is, however, very rare. We describe a new case of recurrent PVNS arising from the temporomandibular joint that was classified as diffuse extra-articular type and was successfully treated surgically. The etiology and clinical features of PVNS are discussed and the previously reported cases in the literature are reviewed.

The finding of reporter gene expression in muscle cells after intramuscular injection of a reporter gene containing DNA has suggested that injection of a certain gene in its naked form could induce an expression of the injected gene. The result proposed the concept, namely DNA or genetic vaccine technology, that injection of an antigen gene could induce a specific immune response against the antigen. Although the concept was initially applied to vaccination technology, the result also means that administration of cytokine genes with anti-tumor activity could exert their functions when they are applied as a naked form of DNA. To test the possibility, plasmid vector containing granulocyte macrophage-colony stimulation factor (GM-CSF) and interleukin-12 (IL-12) genes, which are known as one of the most potent anti-tumor cytokines, were constructed and injected into mice together with syngeneic tumor cells. When the cytokine gene containing plasmid was injected on the same day of tumor cell injection, a tumor mass developed in 4 out of 5 mice tested. Even among the 4 mice, the tumor mass of a mouse disappeared 2 weeks after tumor development. In addition, tumor generation was significantly delayed in cytokine gene injected mice and the average tumor size was about 51.5% that of vector control injected mice. These results suggested that tumor treatment through the injection of multiple cytokine genes with potent anti-tumor activity significantly inhibits tumor development and growth, and that the method could be considered as one of the tools for efficient tumor treatment.

Purpose: The intraoral vertico-sagittal ramus osteotomy (J Craniomaxillofac Surg 20:153, 1992) can be used to reduce high condylar process fractures and recontour hyperplastic condyles while simultaneously correcting the malocclusion. This article presents the technique and reports the clinical results., Patients and Methods: A technique for removal and replantation of the condyloid process using the vertico-sagittal ramus osteotomy and rigid fixation was used to treat 23 patients with markedly displaced, high condylar process fractures and condylar hyperplasia associated with malocclusion., Results: The replanted condyles did not show ischemic necrosis or any functional disturbance when followed for more than 3 years. All patients showed nearly normal mouth opening, with slight mandibular deviation, usually in sixth postoperative month., Conclusions: In selected patients, this technique allows intraoral accessibility to the condyle and its repositioning. The method is particularly useful to treat vertical discrepancies associated with the hyperplastic or hypoplastic condyle.

Purpose: This article describes a vascularized bony window for access to the maxillary sinus and reports the clinical results., Patients and Methods: A bony U-shaped window in the anterior sinus wall was pedicled on the surrounding soft tissue and periosteum. After the described sinus was cleared of disease, the window was repositioned in its original site either using resorbable sutures or not. The method was used in 47 maxillary sinus operations in 45 patients. Twenty-four patients were followed-up for more than 48 months., Results: The vascularized bony window technique showed uneventful healing in all patients and none of the 24 patients reported any problems., Conclusions: The vascularized bony window technique provides a large antrostomy, which gives good access and visibility and results in satisfactory postoperative healing.

Purpose: Various designs for previously reported postauricular skin flaps have the disadvantages of being two-stage procedures, providing a limited pedicle, or requiring microvascular anastomoses. To overcome such problems, a new auriculomastoid fasciocutaneous (AMFC) island flap for orofacial reconstruction has been developed. This article presents the technique and reports the clinical results., Patients and Methods: A long ipsilateral AMFC island flap pedicled by the parietotemporal fascia and based on the parietal branches of the superficial temporal artery, the occipital artery, and the postauricular artery was designed. Twenty-five of these island flaps were used to reconstruct intraoral or external facial defects., Results: The fasciocutaneous flap could be extended to reach any orofacial defect as a single or compound design in a one-stage subcutaneous procedure. Compound types of AMFC island flaps, including scalp, parietal bone, or the parietotemporal fascia were performed successfully based on single vessels. The flap has the characteristics of providing thin and pliable skin, a good color match to the face, and restored sensitivity. The donor defect is designed to be closed directly and concealed behind the ear without ear deformity., Conclusions: This flap is very useful in orofacial reconstruction because the skin quality equals that of the radial forearm flap, without the need for microvascular anastomoses, with many additional advantages and various modifications of design.

The sagittal split ramus osteotomy (SSRO) and the intraoral vertical ramus osteotomy (IVRO) are long established methods for correcting mandibular prognathism, each having its own advantages. However, both procedures have the same disadvantage: the potential for postoperative condylar displacement. The displacement of the condyle is mainly due to the fact that the osteotomy plane is not parallel to the original sagittal plane in which the mandible is repositioned. The author has developed a new ramus osteotomy since 1985 in which the osteotomy plane is theoretically parallel to the original sagittal plane and thereby attempting to decrease the incidence of condylar displacement. This osteotomy was designed additionally to decrease neurosensory disturbances and has the advantages of both methods, and therefore has been named 'intraoral vertico-sagittal ramus osteotomy (IVSRO)'. Initial experience with the 24 prognathic patients operated on by means of the IVSRO indicated excellent clinical results. It has been noted clinically that the IVSRO is very effective in reducing postoperative iatrogenic TMJ symptoms and in treating preoperative TMJ symptoms. It has the additional effect of reducing neurosensory disturbances. This osteotomy seems to be more applicable in mandibular prognathism with excessive flaring of the ramus, particularly that associated with TMJ dysfunction, because the IVSRO has a 'condylotomy effect' and its splitting plane diverges less from the original sagittal plane than that of the SSRO and the IVRO.

The authors have performed 13 cases of vascularized cranial bone grafts for reconstruction of maxillofacial defects since 1986. Two types of flaps were used: the parietal osteofascial flap pedicled to the parieto-temporal fascia based on the superficial temporal artery and the temporalis osteomuscular flap pedicled to the temporalis muscle based on the deep temporal artery. Zygomatico-orbital complex, maxilla and mandible were reconstructed and hemifacial microsomia was also treated. The results of vascularized cranial bone grafts pedicled to fascia were as good as those of grafts pedicled to muscle. There were no major complications. Two types of vascularized cranial bone grafts seem to be useful in reconstruction of maxillofacial defects with avascular recipient beds because of their good blood supply. The parietal osteofascial flap has additional advantages including easy rotation of the flap to the defect, particularly a mandibular defect, and versatile use of fascia without bulkiness for reconstruction of soft tissue defects. This flap can be designed as a full- or partial-thickness cranial bone graft with good vascularity. In this paper, our technique for mandibular and maxillary reconstruction using the parietal osteofascial flap is introduced, and the results compared with our temporalis osteomuscular flap technique are reported.