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PubMedDate not supplied

[Histomorphology of secondary cartilage in human fetal mandibles].

The aim of this study was to provide a histomorphological analysis of some secondary cartilages of mandible and temporal bone as observed in human fetuses 18-22 weeks old. The behavior of cartilage was studied in both these regions, which were decalcified, cut at 10 mu, stained with Mallory staining and examined by optical microscopy. In mandible symphysis menti and condylar cartilage were described. The symphysis appeared to be formed by a fibrous cartilagineous structure surrounded by membranous bone. This structure seems be round in the caudal sections and ovoidal in the rostral sections with the major axis perpendicular to the mean sagittal plane. Meanwhile the condyle is formed by secondary cartilage which may be appreciated in this development stage 5 zona. Secondary cartilage was observed also in the temporal bone nearby the primitive glenoid fossa. The development and the importance of these cartilagineous structures are discussed.

Abortion, Spontaneous↗
PubMed1998

Problems associated with the atrophic mandible.

A range of treatment options has been presented regarding the use of dental implants to rehabilitate patients who otherwise have compromised function using conventional tissue-borne prostheses. This patient population offers significant challenges to both the surgeon and the prosthodontist. Generally speaking, IODs retained on two or more endosteal osseointegrated implants; transosteal, subperiosteal, ramus frame implant-supported and implant-retained prostheses, and a totally implant-supported design offer options to treat the severely atrophic mandible. When bone support or volume is so lacking that augmentation procedures are required, bone grafting can be considered as a treatment option. The state-of-the-art of implant treatment for the atrophic mandible offers to the dental professional and patient a variety of options. Thus far, it is too early to make specific recommendations as to which treatment offers the best option for each patient. It is fair to say that the ISP remains the gold standard against which other treatments can be compared.

Alveolar Ridge Augmentation↗
PubMed1997

Repair of bone defect in primate mandible using a bone morphogenetic protein (BMP)-hydroxyapatite-collagen composite.

The purpose of this study was to evaluate a hydroxyapatite (HA)-collagen (Col)-bone morphogenetic protein (BMP) composite as an osteoinductive bone substitute. Partially-purified BMP from bovine bone was mechanically mixed with highly purified type I collagen from calf dermis and then subsequently mixed with pure synthetic hydroxyapatite granules or block. The HA-Col-BMP composite, or the HA-Col composite as a control, was implanted in a surgically-induced mandible bone defect (6 x 7 x 10 mm) in an adult Japanese monkey. The mandible was excised three months after implantation and studied histologically. The BMP-containing implant induced much more new bone than the control implant in all experimental animals of each group, with either HA granules or HA block. Newly formed bone was attached tightly to HA and infiltrated deeply into the pores of the HA of the BMP-containing implant, while fibrous tissue existed between the host bone and HA in the control implant. Thus, we conclude that an HA-Col-BMP composite could be a superior biomaterial for a bone substitute.

Animals↗
PubMedDate not supplied

A comparative clinical study of three different endosseous implants in edentulous mandibles.

The purpose of this prospective study was to investigate the clinical outcome and marginal bone resorption of three different endosseous implants placed in the anterior mandibles of 15 elderly patients. Eleven women and 4 men (ranging from 65 to 80 years, mean 71 years) had three different endosseous implants placed in the anterior mandible; one titanium plasma-sprayed cylinder implant (4-mm diameter), one titanium cylinder implant with hydroxyapatite coating (4-mm diameter), and one standard threaded titanium implant (3.75-mm diameter). Three months later, at the second-stage surgical procedure, ball abutments were connected and an overdenture was placed. At 12, 24, and 36 months, marginal bone resorption and Periotest values were recorded. None of the implants was lost in this period. An analysis of variance with repeated measurement was performed annually to test the existence of significant differences between the implants. When differences appeared, paired t tests were used to identify which differences were significant. Bonferroni multipliers were used to adjust for multiple testing. When marginal bone resorption was concerned, threaded titanium and hydroxyapatite-coated implants had significantly better scores than titanium plasma-sprayed cylinder implants. Periotest values for hydroxyapatite-coated implants were significantly better than test values for the other implants after 2 years. After 3 years significance was obtained between hydroxyapatite and screw-shaped implants only (P < .05). It was concluded that titanium plasma-sprayed cylinder implants have a less favorable prognosis than the other implants used in this study.

Aged↗
PubMed2000

Reconstruction of the pediatric maxilla and mandible.

BACKGROUND: The creation of osseous defects in the upper and lower jaws in children is an uncommon occurrence. It is therefore likely that a head and neck reconstructive surgeon will accumulate only limited experience in restoring such defects. We have reviewed 7 pediatric bone-containing microvascular free flap reconstructions in 6 patients for reconstruction of the upper or lower jaws. Three patients were available for long-term follow-up to evaluate the effect of osseous free flap reconstruction on function and growth and development of the donor site. DESIGN: Retrospective review. SETTING: Academic tertiary referral center for otolaryngology. PATIENTS AND METHODS: Six pediatric patients ranging in age from 8 to 16 years underwent 2 fibular, 4 scapular, and 1 iliac free flap procedure for restoration of 2 maxillary and 5 mandibular defects from 1992 to 1997. Three of the 6 patients were available for long-term follow-up to assess the postoperative donor site function in an effort to determine the effect of this surgery on long-term donor site morbidity and development. RESULTS: Two patients were lost to follow-up, and 1 died secondary to complications related to distant metastatic disease. Three of 6 patients were observed for 2 years 6 months, 4 years, and 4 years 2 months, respectively. Two of the 3 patients who were observed long term have undergone full dental rehabilitation and currently maintain a regular diet and deny pain with mastication or deglutition. One patient did not require dental rehabilitation. All 3 patients demonstrate gross facial symmetry and normal dental occlusion. Assessment of the fibular donor site demonstrated normal limb length and circumference. The patients denied pain or restriction to recreational activity. Scapular donor sites demonstrated normal range of motion, strength, and shoulder stability. CONCLUSIONS: Free flap reconstruction of the pediatric maxilla and mandible requires harvesting bone from actively growing donor sites. We have found no evidence of functional deficit after bone harvest from the fibular or scapular donor sites. Patients demonstrate normal growth at the donor sites, and symmetry of the mandible and maxilla is preserved.

Adolescent↗
PubMed1975

Surgical management of osteogenic sarcoma of the mandible.

Osteogenic sarcoma is the most common malignant tumor of the mandible. It is less aggressive than osteogenic sarcoma of the long bones, and mortality is often due to local persistence or intracranial extension. We report such a case to emphasize that disarticulation of the mandible is necessary, since clinical and pathologic evaluation of tumor extent may be impossible. Except for parasymphysial lesions, disarticulation with midline hemimandibulectomy and frozen section assessment of all margins is recommended.

Adult↗
PubMed1979

Treatment of osteogenic sarcoma of the mandible.

Osteogenic sarcoma of the mandible is a rare tumor, comprising less than 0.5% of all head and neck tumors, and, even in large institutions, the experience in management of such tumors is limited. Current therapy for osteogenic sarcoma of the long bones is based on a more extensive experience in large centers and includes a major role for chemotherapy. We report two cases of osteogenic sarcoma of the mandible that were treated by combined chemotherapy, radiation therapy, and surgery. The expected disease-free survival of patients with this disease, treated by surgery alone, would have been less then 50% in the first year. The survival of these two consecutive patients for more than one year, free of disease, is significant and encourages further use of this type of treatment.

Adolescent↗
PubMed1982

Treatment of fractures of the edentulous mandible.

The reduction and fixation techniques for treatment of fractures of the edentulous mandible are varied, although all the operative techniques are based on the fundamental principles of adequate bone fragment apposition and immobilization. The techniques include the following: (1) analgesia and soft diet, (2) closed reduction with splint fixation, (3) open reduction (intraoral or extraoral) with transosseous wire ligation, (4) percutaneous intramedullary pinning, (5) intraoral open reduction with bone graft and maxillomandibular fixation, (6) external splint fixation appliance, (7) extraoral open reduction and fixation with malleable mesh, and (8) extraoral open reduction and fixation with bone plating (metacarpal, lateral compression, and eccentric dynamic compression plate [EDCP]). We review the various modalities of therapy for this challenging problem, with the strengths and weaknesses of each technique. In addition, we discuss a relatively new method of fracture fixation in North America, the EDCP, and our experience using it to treat 17 fractures of the edentulous or nearly edentulous mandible, with a 94% bony healing rate.

Bone Transplantation↗
PubMed1989

Aneurysmal bone cyst of the mandible.

Aneurysmal bone cyst is an uncommon benign lesion that rarely presents in the craniofacial region. No prior reports of this entity involving the mandible could be found in the otolaryngologic literature, and it has been reported only infrequently in the maxilla. Two previously unreported cases originating in the mandible are presented with a review of the literature, pathology, and diagnosis of this lesion. Treatment of this lesion consists of complete surgical removal and immediate bone grafting for reconstruction.

Adolescent↗
PubMed1998

New syndrome? Prominent, constricted ears with malformed condyle of the mandible.

We report on several relatives in 5 generations of one family with prominence of the ears, with a marked constriction at the junction between the lower and middle thirds of the pinna. Computerized tomography and radiographs in the propositus and his affected father showed abnormalities of the condyle of the mandible. The propositus had more severe changes in the condyle with microstomia and reduced range of motion of the mandible in the temporomandibular joint. There was no hearing loss or abnormalities of the bones of the middle ear.

Child↗
PubMed1998

A modified protocol for early treatment of osteomyelitis and osteoradionecrosis of the mandible.

BACKGROUND: The treatment of osteoradionecrosis (ORN) and early chronic osteomyelitis (COM) of the mandible and maxilla is controversial. Hyperbaric oxygen (HBO) at two to three times the atmospheric pressure at sea level can result in tissue oxygen tension of almost 400 mmHg. Herewith HBO increases oxygen supply in hypoxic tissue, thus inducing fibroblastic proliferation and capillary formation. METHODS: From 1981 to 1991, we used a monoplace chamber and since 1992, we have also had a multiplace chamber for HBO treatment. Hyperbaric oxygen was given at 2.5-2.8 atmosphere absolute pressure (ATA) for 90-120 minutes, once per day. The patients had five to 10 preoperative and five to seven postoperative sessions. Surgical therapy consisted of decortication of the affected bone, subsequently covered with a free periosteal transplant from the tibia. RESULTS: Thirty-six patients with ORN and 33 with COM of the mandible and maxilla was treated with this protocol. The median follow-up time in this material is 34 months, with a minimum of 10 months. Thirty-six ORN patients (92%) and 26 COM patients (79%) have remained symptom-free after the first treatment period. Three failed ORN patients were successfully treated with a free microvascular flap. The seven failed COM patients have been retreated, and five of them have occasional clinical symptoms. CONCLUSIONS: Hyperbaric oxygen is a promising adjunct to surgery in the treatment of mandibular and maxillary ORN and COM. Using this protocol, the necessary HBO treatment sessions have been reduced from earlier protocols, without adverse effect on the outcome.

Adolescent↗
PubMedDate not supplied

Bone resorption of the mandible in progressive systemic sclerosis.

Five of 16 patients with progressive systemic sclerosis were found to have bone resorption at the angle of the mandible. This finding appears to be closely related to the tightness of the skin of the face, atrophy of the masseter and pterygoid muscles, small size of the oral orifice, and a significantly high frequency in blacks. The mandible must therefore be added to the list of those bones that can be resorbed in progressive systemic sclerosis.

Adolescent↗
PubMedDate not supplied

Comparative study of technetium-99m bone scans and orthopantomography in determining mandible invasion in intraoral squamous cell carcinoma.

The accuracy of preoperative assessment in determining invasion of the mandible by intraoral squamous cell carcinoma was analyzed in 48 patients who underwent mandibulectomy, and the results correlated with the histopathological reports of the resected specimens. Only 50% of the patients underwent the "ideal" surgery based primarily on clinical judgement, whereas 10 patients in the series were significantly undertreated. Clinical judgement and routine preoperative x-rays are accurate in cases where there is gross involvement of the mandible (17 of 19) but are significantly less successful in determining early bone invasion, invasion of the periosteum, or periosteal new bone formation. In such cases (26 of 48), a technetium-99m bone scan provides additional information. A grading system for reporting orthopantomographics (OPTs) and bone scans has been developed and utilized to form a reference grid to determine the optimum extent of mandibular surgery. The results show that using this protocol, unnecessary mandibular surgery may be reduced and inadequate surgical excision avoided.

Carcinoma, Squamous Cell↗
PubMed2006

A clinical case report: interface analysis of a successful well-functioning transmandibular implant from a cadaver mandible.

Transmandibular implants (TMI) are indicated both for functional reconstruction of the severely atrophic mandible and when routine augmentation is unpredictable. This study investigates the interface of bone around a TMI, retrieved from the cadaver. The TMI had successfully functioned for 7 years. The mandible was immersed in 10% formaldehyde and sectioned into nine appropriate pieces. Samples were embedded in polymethylmethacrylate, and cut around the transosseous posts and cortical screws in both vertical and horizontal sections. Samples were analyzed at 400 MHz (nominal lateral resolution, 2.5 microm) using a UH3 Scanning Acoustic Microscope (Olympus, Tokyo, Japan). The middle of implant specimens 1-4 were cut to 50 microm, and stained by toluidine blue for light microscopy. Dental X-rays showed no bone resorption around any implant. On a 2-mm lateral scan, almost uniform interface space was seen between bone and implant surface in cortical screws. There are wider spaces around the transmandibular posts in the superior area. Histology revealed the small area of direct contact. There is bone marrow space in the interface, with no significant fibrous tissue. We interpret these results at the interface to be because of adaptation for stress distribution.

Adaptation, Physiological↗
PubMed1981

Primary tumours and tumour-like conditions of the mandible.

Reports on comprehensive mandibular tumours are very rare. The present article describes a total of 81 primary tumour and tumour-like lesions of the mandible seen at the University Hospital, Banaras Hindu University, during last 16 years. In the mandible the ratio of odontogenic to nonodontogenic tumors is 1.6:1. Ameloblastomas constitute 56% of the odontogenic tumors. Among the benign mesenchymal tumours of the jaw 58% are neoplastic and 42% are nonneoplastic in which cementoostoid tissue is laid down secondary to inflammatory process. Over all 40 cases are benign 28 potentially malignant (ameloblastoma) and 13 are malignant lesions. Among the malignant mandibular tumours, bone tumours are more common than the soft tissue sarcomas. Microscopically mandibular osteosarcomas are better differentiated than similar tumours in the long bones. Local, segmental, or radical surgery seems to be the treatment of choice in the mandibular tumours.

Adolescent↗
PubMed1983

Management of osteoradionecrosis of the mandible with myocutaneous flaps.

Involvement of large areas of the mandible or the entire mandible with osteoradionecrosis may result in severe functional disability and cosmetic deformity. The use of a well-vascularized pectoralis major myocutaneous flap from outside the original field of irradiation has been successful in obtaining functional and cosmetic goals. Myocutaneous flaps provide bulk for contour and tissue support, and their rich vascular supply promotes healing of the heavily irradiated soft tissue and bone. Successful bone grafting for mandibular reconstruction may follow control of the osteoradionecrosis.

Carcinoma, Squamous Cell↗
PubMed1988

Primary malignant lymphoma of the mandible.

From 1945 through 1985, 32 cases of primary lymphoma of bone were treated at the University of Iowa Hospitals and Clinics. Sixteen cases (50%) demonstrated the lesion in the long tubular bones with a predilection for the lower and upper extremities. The frequently involved flat bones (six cases) were the bones of the pelvis. There were only three cases (9%) where the mandible was the primary site. In this report, the literature is reviewed and three cases with primary lymphoma of the mandible are presented.

Adolescent↗
PubMed2004

Use of Kirschner wire in mandible reconstruction: a case report and review of the literature.

Reconstruction of massive defects in head the and neck usually requires different tissues such as skin, bone, and muscle in three-dimensional organization. Therefore, reconstruction of mandibular defects in particular include many difficulties for the head and neck, and for reconstructive surgeons. Various techniques and materials are available, and each has some advantages and disadvantages. But no materials or methods have all the reconstructive requirements. The surgeon's choice of techniques should be safe, simple, economic, and effective. We present a patient with a massive facial defect that was reconstructed successfully by using a 2-mm K wire with a free transverse rectus abdominis myocutaneous flap, and we also review the literature about the use of K wires in mandible fixation and reconstruction. We think that K wires should be kept in mind as a readily available, easily applicable, safe, inexpensive, and stable prosthetic material for mandible reconstruction, especially in cases with advanced disease.

Bone Wires↗