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At least 289 records · Page 16Linked to original sources
PubMed2004

Collagen type I and III metabolism in assessment of mandible fractures healing.

PURPOSE: The aim of this work was estimation of the PIIINP, PICP and ICTP concentrations in blood serum during non-complicated mandible fracture healing; settlement of dependences between kinetics of changes of examined markers with reference to particular bone fracture phases and applied treatment methods; the determination of usefulness of collagen metabolism markers type III and I for the monitoring of mandibular fracture healing. MATERIAL AND METHODS: The material was blood serum of men aged 20-30 years, who were treated for mandible fractures in Maxillofacial Clinic Medical University of Bialystok. Depending on the treating method, examined patients were divided into two groups. Patients treated with non-operative method were I group (n = 31), II group was made of patients treated with surgery (n = 33). The concentrations of markers measured on the 2nd, 14th, 42nd, 90th day after trauma and in II group these substances were measured additionally on the 2nd and 14th day after surgery. Control group consisted of 20 healthy men the same age. Concentrations of markers were measured with the radioimmunological method (RIA). RESULTS: Regular process of mandible fracture healing in men in various periods occurs with PICP, PIIINP and ICTP concentration changes in blood serum. CONCLUSIONS: Changes of maker concentration show that, mandible fracture healing treated non-operatively is a more dynamic process than stable osteosynthesis method applied. Lack of positive correlation of the PIIINP and PICP concentration in blood serum of patients in two examined groups can indicate on the different mechanisms of mandible fracture healing connected with different methods of the treatment.

Adult↗
PubMed2005

[Elimination of mandibular defects with dosed distraction. Part III. Use of dosed distraction for restricted osteoplasty in subtotal and end defects of the mandible].

Two variants (3(rd) and 4(th)) of non-free mandible osteoplasty with the use of compression-distraction apparatus (CDA) elaborated during the war in Afghanistan are described by the author. The 3(rd) variant was used in cases of vast combined defects of lower part of the face when two-sided osteotomy of both mandible stumps in order to create mobile mandible fragments of the length of 2.5 cm and their follow-up shift to the middle line of the face with the help of CDA is made. Distraction of callosity and soft tissues stimulated histogenesis that led to substitution of big osseous-soft tissue defect of lower part of the face. The 4(th) variant had two stages: 1(st) stage resulted in reconstruction of mandible branch, the 2(nd) -- in reconstruction of mandible head. In such a way the new temporomandibular joint using own tissues of the patient was created without application of allotransplant or titanium explant.

Afghanistan↗
PubMedDate not supplied

Comparison of tensile strength of resorbable plating systems used in monocortical mandible angle osteotomy repair.

OBJECTIVE: To determine the usefulness of resorbable plating systems in load-bearing applications of the mandible and the location of critical failure. METHODS: An osteotomy was created in 24 fresh cadaveric mandibles at the angle and fixated by the Champy technique with similar resorbable craniofacial plating systems from 4 manufacturers. Each mandible was held rigid as a material test system applied a downward force anteriorly. The critical tolerance was measured and the type of failure was noted. RESULTS: Critical failure occurred at forces from 34.6 to 137.8 N. We found a statistically significant difference between the plating groups (P<.001 for all comparisons). The point of failure was almost uniformly at the plate. CONCLUSIONS: Critical failure was overwhelmingly due to rupture of the plate rather than to stripping or shearing of the screws as had been strongly expected. We found differences in plate strengths for this particular application and did not evaluate their respective long-term resorptive properties. We do not advocate that single resorbable plate fixation be the sole means of mandible angle fracture fixation, regardless of the plating system used.

Absorbable Implants↗
PubMed1981

Sagittal ostectomy of the mandible for floor of mouth cancer.

The removal of a full-thickness portion of the anterior part of the mandible can result in significant cosmetic deformity and serious functional disability. Anterior sagittal ostectomy of the mandible obviates the need for resection of the mandible. This surgical technique has the following advantages: (1) permits an en bloc resection of the entire lingual cortical plate of the mandible and the floor of the mouth, (2) maintains facial contour and oral cavity function, (3) can be combined with any soft-tissue reconstructive procedure, and (4) does not require a future mandibular reconstructive procedure.

Carcinoma, Squamous Cell↗
PubMed1997

An adolescent female Neandertal mandible from Montgaudier Cave, Charente, France.

In 1974, an incomplete human mandible was discovered in the site of Montgaudier Cave, along the Tardoire (Charente), France. The mandible was found in association with stone tools and animal bones in geological deposits referable to the very end of the Middle Pleistocene or the beginning of the Upper Pleistocene. The mandible preserves much of the anterior part of the body and three permanent teeth: left lateral incisor, canine and first molar. Estimates based on tooth eruption of modern humans, as well as occlusal wear and root development, suggest an age at death of between 12.5 and 14.5 years. Morphologically, the fossil possesses features, such as a lack of a chin and multiple mental foramina, which have been observed on immature Neandertal mandibular specimens from Europe. Comparison with these immature European Neandertals indicates that the jaw and teeth of the Montgaudier mandible are small for its chronological age, suggesting it was that of a female.

Adolescent↗
PubMed1992

Three-dimensional finite element stress analysis of the dentate human mandible.

The biomechanical events which accompany functional loading of the human mandible are not fully understood. The techniques normally used to record them are highly invasive. Computer modelling offers a promising alternative approach in this regard, with the additional ability to predict regional stresses and strains in inaccessible locations. In this study, we built two three-dimensional finite element (FE) models of a human mandible reconstructed from tomographs of a dry dentate jaw. The first model was used for a complete mechanical characterization of physical events. It also provided comparative data for the second model, which had an increased vertical corpus depth. In both cases, boundary conditions included rigid restraints at the first right molar and endosteal cortical surfaces of the articular eminences of temporal bones. Groups of parallel multiple vectors simulated individual masticatory muscle loads. The models were solved for displacements, stresses, strains, and forces. The simulated muscle loads in the first model deformed the mandible helically upward and toward its right (working) side. The highest principal stresses occurred at the bite point, anterior aspects of the coronoid processes, symphyseal region, and right and left sides of the mandibular corpus. In general, the observed principal stresses and strains were highest on the periosteal cortical surface and alveolar bone. At the symphyseal region, maximum principal stresses and strains were highest on the lower lingual mandibular aspect, whereas minimum principal stresses and strains were highest on its upper labial side. Subcondylar principal strains and condylar forces were higher on the left (balancing or nonbiting) side than on the right mandibular side, with condylar forces more concentrated on the anteromedial aspect of the working-side condyle and on the central and lateral aspects of the left. When compared with in vivo strain data from macaques during comparable biting events, the predictive strain values from the first model were qualitatively similar. In the second model, the reduced tensile stress on the working-side, and decreased shear stress bilaterally, confirmed that lower stresses occurred on the lower mandibular border with increased jaw depth. Our results suggested that although the mandible behaved in a beam-like manner, its corpus acted more like a combination of open and closed cross sections due to the presence of tooth sockets, at least for the task modelled.(ABSTRACT TRUNCATED AT 400 WORDS)

Computer Simulation↗
PubMed1985

A study of the position of the mandibular foramen in the adult human mandible.

Eighty dry, adult human mandibles of East Indian ethnic origin and bilateral eruption of third molar teeth were examined to measure the location of the mandibular foramen. The position of the foramen was found to be variable. However, the foramen was predominantly located at the anteroposterior midpoint of the ramus halfway between the mandibular notch and the lower surface of the mandible and two thirds of the way down a line joining the coronoid process to the angle of the mandible. In the majority of the mandibles studied the foramen was located below the occlusal surfaces of the molar teeth. It is concluded that the marked variability in the position of the mandibular foramen may be responsible for an occasional failure to block the inferior alveolar nerve.

Humans↗
PubMed2006

Radiological trace of mandibular primary growth center in postnatal human mandibles.

The mandibular primary growth center (MdPGC) of human fetus was conspicuously defined in the soft X-ray view of fetal mandibles. As the peripheral adaptive growth of mandible advances during the postnatal period, the MdPGC image became overshadowed by condensed cortical bones in soft X-ray view. In this study, we traced a sclerotic sequela of MdPGC during the postnatal period. Panoramic radiograms of 200 adults and soft X-ray views of 30 dried adult mandibles were analyzed by statistical methods. The former clearly showed an MdPGC below the middle portion of apices of canine and first premolar, which was distinguishable from mental foramen, and the latter also showed the MdPGC at the same area as a radiating and condensed radiopaque image, measuring 0.5-1.0 cm in diameter. This MdPGC position was seldom changed in the elderly people, even in the edentulous mandibles. Additionally, in the radiological examination, the benign tumors including odontogenic cysts hardly involved the MdPGC, while the malignant tumors of both primary and metastatic cancer frequently destroyed the MdPGC.

Adolescent↗
PubMedDate not supplied

Patterns of spread of squamous cell carcinoma to the ramus of the mandible.

Patterns of spread of squamous cell carcinoma to the ramus of the mandible have been studied. In nonirradiated mandibles, tumor in the ramus was found to have spread in continuity from tumor within the body. In 22 of 27 specimens (81.5%) with established invasion of the molar region of the body, tumor spread was either confirmed to the body or to the body and the anterior part of the ramus. The remaining five cases showed extensive spread within the ramus. It was concluded that a more conservative approach to resection of the ramus may be safe on pathologic grounds in the nonirradiated mandible. In postirradiation mandibles, direct invasion through cortical bone was seen in addition to direct spread from the body. Tumor spread to the ramus was seen in nine of 12 specimens (75%), and in each case was both diffuse and extensive. It was concluded that a conservative approach to resection of the ramus is not safe on pathologic grounds after radiotherapy.

Carcinoma, Squamous Cell↗
PubMed1989

MRI of the mandible.

Eighteen patients with abnormalities of the mandible and two normal volunteers were studied with MRI. Correlation was made with MR, CT, plain X-rays, clinical examination, and surgical findings when possible. In primary tumors of the mandible, MR was able to differentiate between solid and cystic lesions. In the cases of secondary invasion of the mandible by malignant tumors, MR was able to demonstrate replacement of the normal high signal bone marrow by low signal tumor. In some cases, the extent of marrow involvement shown on MR and confirmed at surgery was significantly underestimated by clinical examination, plain films, and CT. From this limited experience, it appears that MR may play an important role in imaging pathology of the mandible.

Humans↗
PubMed1994

[Morphometric studies on the fetal development of the human mandible].

Serial sections of eleven human mandibles of embryos and fetuses ranging in size from 18 mm CRL to 66 mm CRL were computer-graphically reconstructed. The extension of the Meckel cartilage and the mandibular bony structures were morphometrically studied. In emphasis the study encompassed measurements portraying length, width, dorsal opening angle, and the position of the mental foramen. In addition five mandibles of human embryos and fetuses with a size range between 30 and 50 mm CRL were radiographically examined. Results showed that in the younger specimens between 21 and 29 CRL size development of the structures of the mandible and the development of overall fetal body size take place independently from each other. During further development a change in the form of the mandible from a wide V over an acute V to a more rounded U form was observed.

Cartilage↗
PubMed1993

[Cephalometric studies on the mandible following the dorsal transposition of the masseter. An experimental animal study].

Changes in growth dimension and growth direction in three to four week old rabbits were studied cephalometrically after surgically repositioning the anterior part of the superficial masseter muscle dorsally to the angle of the mandible (n = 14). Only a sham operation was performed on 13 animals. Twelve months after the procedure the lower jaws were taken out and cleaned by boiling. X-rays were taken of the right and left part of the mandible. All x-rays were measured cephalometrically and the measurements evaluated statistical (alpha = 0.05) with the U-test (Mann/Whiteney). We found a statistically significant shorter mandible and an enlargement of the gonion angle, which indicate a vertical growth direction. The processus condylaris was unchanged. It can be assumed that the growth of the mandible can be altered permanently by muscle reposition, especially in cases with dysmoysis, a term in the literature first proposed by Eschler.

Animals↗
PubMed1999

[Comparative studies of Brånemark implants in the irradiated and not irradiated mandible].

A comparative study was carried out of 276 Brånemark fixtures in the irradiated and nonirradiated anterior mandible with a mean follow-up period of 58.2 months. Postoperative radiotherapy with 60 Gy and 100% isodose for the anterior mandible using a 6-MV linear accelerator, conventional fractioning, and a split-course technique was administered in the irradiated patient group. HBO therapy was not applied. A statistical difference in the 5-year success rate between the irradiated and nonirradiated group was not found. Nevertheless, a significantly higher rate of perioperative soft tissue complications at implant insertion was seen in the irradiated group. The statistical analysis showed no significance for sex, interval between radiation and implant insertion (with a minimum of 10 months), or type of periimplant soft tissue (regional vs. flap). The prognosis for implants in the irradiated mandible was, however, statistically improved (n = 0.0035) when the healing period was longer than 4 months. Mobile periimplant soft tissue proved to be the main problem regardless of radiation load. Late complications have not been observed so far. The available results and clinical studies support a positive assessment of the regenerative potential of the irradiated mandible with regard to osteointegration of endosseous implants. A preceding radiotherapy up to 60 Gy should therefore not be considered as a contraindication for an implant/prosthetic rehabilitation.

Adult↗
PubMed1999

[Augmentation of the extremely atrophied maxilla and mandible by autologous calvarial bone transplantation].

Rehabilitation in patients with severe alveolar ridge atrophy of the maxilla or mandible is problematic and can often only be achieved by long-term treatment. In most cases, autologous bone grafting with iliac crest bone has been used to augment severely atrophied upper jaws. In our experience, iliac bone grafts are less useful, since iliac bone appears to be of inferior quality; in elderly osteoporotic women, the bone is soft, indentable, and of poor osteogenic potency. In our department, we have been using only autologous calvarial bone grafts for augmentation of alveolar ridge atrophy since 1993. The bone is removed from the outer table of the skull only, trimmed to the alveolar ridge, und fixed with titanium lag scews. The skull defect created is covered with crushed bone or a titanium mesh to avoid aesthetic problems. Insertion of dental implants follows after a healing period of the bone grafts of 5-6 months. A total of 63 patients underwent calvarial split-graft augmentation; augmentation of the maxilla and mandible was carried out in 15 of these patients, of the maxilla only in eight, and of the mandible only in 40. The investigations 1 year later showed a resorption rate of approximately 10%. This is lower than when using iliac bone grafting. The resorption results were stable between 6 and 12 months after augmentation. Using dental implants (12 patients with 32 implants), the resorption rate was low and constant. We have never seen total loss of bone grafts or intracranial complications. All patients were pleased with the treatment. In our opinion, severe alveolar atrophy of the maxilla or mandible should be compensated for by augmentation with autologous calvarial bone grafts to obtain good long-term results.

Adult↗
PubMed2006

Osteoradionecrosis of the mandible: minimized risk profile following intensity-modulated radiation therapy (IMRT).

BACKGROUND AND PURPOSE: Osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between < 1% and ~ 6%. Intensity-modulated radiation therapy (IMRT) is expected to translate into a further important reduction of ON. The aim of this descriptive study was to assess absolute and relative bone volumes exposed to high IMRT doses, related to observed bone tolerance. PATIENTS AND METHODS: Between December 2001 and November 2004, 73 of 123 patients treated with IMRT were identified as subgroup "at risk" for ON (> 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12-46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance. RESULTS: Using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm(3) were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with lingual decortication, was observed. CONCLUSION: Using IMRT, only very small partial volumes of the mandibular bone are exposed to high radiation doses. This is expected to translate into a further reduction of ON and improved osseointegration of dental implants.

Adult↗
PubMed2001

[Quantitative computerized tomography of bone mineral density of the mandible. Imaging of topographic distribution of bone mineral density in automated segmentation of mandibular structures].

PURPOSE: Confirmation of a new technique for evaluating bone mineral density (BMD). Colored coded imaging of topographical distribution of bone mineral density in the spongy substance. METHOD: For 20 patients, dental CT examinations of the mandible were made in axial slices. Spongy substance and cortical bone pixels were automatically segmented at foramina mentalia level by means of threshold fixation. The segments were separated in areas relevant to implantology. For each region, BMD was measured by means of quantitative computed tomography (QCT). Spongiose substance of 20 mandibles was segmented by using three threshold intervals to image topographical BMD distribution. RESULTS: Cortical bone and spongy substance could be automatically segmented for 20 mandibles. BMD could be measured in each region. The results were comparable with those of other techniques. Three threshold intervals were segmented for 20 mandibles in the spongy substance to depict topographical BMD distribution. CONCLUSIONS: Areas of low BMD can be detected by imaging topographical BMD distribution. This way, subjective rating by the examiner is eliminated.

Adolescent↗
PubMed2001

Effects of running exercise on the mandible and tibia of ovariectomized rats.

To examine the effects of running exercise on the mandible and tibia of ovariectomized (OVX) rats, 26-week-old sham-operated (Sham) and OVX rats 1 week post-ovariectomy were subjected to non-exercise (Sham-Cont and OVX-Cont) and exercise (Sham-Exc and OVX-Exc) for 8 weeks. OVX induced a significant decrease in alkaline phosphatase (ALP) and an increase in tartrate-resistant acid phosphatase (TRAP) activity and a reduction of 17beta-estradiol in the serum. In OVX-Cont rats, histology and bone mineral density (BMD) showed bone loss in the proximal tibia, and histology, soft X-ray photographs and bone marrow area (BMA) revealed enlargement of the bone marrow cavity in the neck of the condylar process. In OVX-Exc rats, exercise significantly increased ALP activity, decreased TRAP activity and markedly elevated serum progesterone levels. Histology and BMD in the tibia and histology, X-ray photographs and BMA in the mandible were comparable to those in Sham rats. In Sham-Exc rats, unexpected decreases were observed in serum enzymes and hormones, but the histology and BMD in the tibia and histology, X-ray photographs and BMA in the mandible were very similar to those in Sham-Cont rats, suggesting a decrease of bone turnover with no change of bone mass in the tibia and mandible. We conclude that exercise has a beneficial effect not only on bone loss in the tibia, but also on differential changes in the neck of the condylar process, perhaps by increasing serum levels of progesterone in OVX rats.

Alkaline Phosphatase↗
PubMed2006

[Mental neuropathy and pathologic fracture of the mandible as initial symptoms of metastatic prostate carcinoma].

BACKGROUND: Distant metastases of solid tumors account for about 1% of all malign neoplasms. In about 30% of all patients who present with an oral metastasis, the distant primary tumour has not been diagnosed yet. CASE REPORT: We report the case of a 71-year-old man who clinically demonstrated unilateral mental neuropathy as well as pathologic fracture of the mandible. Prostate carcinoma was identified as a primary tumor. Clinically, there was significant hypesthesia of the skin area innervated by the left inferior alveolar nerve. X-ray examination revealed an osteolytic lesion of the ascending ramus of the mandible as well as a pathologic fracture of the mandible. Further imaging showed an extensive neoplasm of the mandible and adjacent soft tissues and significant supraclavicular lymph node enlargement. The diagnosis of metastatic carcinoma of the prostate was histopathologically confirmed. CONCLUSION: Mental neuropathy without a dental focus indicates screening for an osseous metastasis. In cases of left-sided supraclavicular lymph node enlargement in men over 45 years, metastatic prostate carcinoma must be excluded.

Aged↗