Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MANDIBLE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources
PubMed1987

Electron microscopic study of chondroid tissue in the cat mandible.

This paper deals with electron microscopic appearance of chondroid tissue. Samples from eight cat mandibles were studied without decalcification. The ultrastructural characteristics of the chondroid tissue cells are common with young osteocytes. The interterritorial matrix of chondroid tissue is mineralized, being constituted of large collagen fibrils and calcospherites. The compositions of these parts of the chondroid tissue matrix and of bony matrix are similar but they are two different tissues. The pericellular matrix of the chondroid tissue consists of finely branched filaments, thin collagen fibrils, and an abundant ground substance. It resembles a cartilage matrix and contains type II collagen which is not present in bony matrix.

Animals↗
PubMedDate not supplied

Alterations in cefalosporin levels in the serum and mandible of hyperlipaedemic rats after co-administration of ibuprofen.

Several interactions between antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) have been described in the literature, and it has been reported that hyperlipidaemia induces significant changes in cefalosporin levels. The aim of this study was to determine the changes in the levels of several cefalosporins in the serum and mandible after ibuprofen co-administration in hyperlipaedemic rats. One hundred and forty male Wistar rats were used and divided in 4 groups (A-D), each of which was further divided into 5 subgroups (1-5), either with placebo or with various treatment regimes. The co-administration of NSAIDs led to increased cefalosporin levels in both control and hyperlipidaemic animals. Hyperlipidaemia was also found to augment cefalosporin levels. These observed increases might be due to the displacement of the cephalosporins from their binding sites in serum albumin and tissue proteins in the presence of ibuprofen. NSAIDs showed a greater binding affinity for tissue proteins compared to the cephalosporins, and probably play an antagonistic role in protein binding, resulting in higher concentrations of antibiotics.

Animals↗
PubMed2000

Fixed lingual arch appliance for compliance-free unilateral molar distalization in the mandible. Three case studies.

An asymmetrically activated lingual arch appliance enables rapid, unilateral molar distalization in the mandible without active patient compliance. Using the segmented arch technique, the biomechanics involve only the tooth moved, in accordance with the 2-tooth concept, with a large, multi-rooted tooth segment acting as an anchoring unit. The anchorage system requires no maxillary involvement.

Activator Appliances↗
PubMed2005

The cost of being an omnivore: mandible wear from plant feeding in a true bug.

Evolutionary and ecological transitions from carnivorous to omnivorous feeding may be constrained by the ability of the animal to cope with disparate types of foods, even if preadaptations for such behaviour exist. The omnivorous true bug, Dicyphus hesperus (Hemiptera: Miridae) requires both animals (small, soft-bodied insects) and plants in its diet and obtains the majority of its dietary and metabolic water from plant feeding. Serrations on the lateral margins of the mandibular stylets wear with age, and this wear is exacerbated when the insects feed on plants compared to those provided free water and no plants. D. hesperus that feed on plants attack fewer prey but consumed similar amounts of prey tissue compared to individuals that were provided free water. Although others have shown mandible wear for plant-chewing animals we show for the first time that plant feeding can impose similar wear on plant-piercing animals as well.

Animal Feed↗
PubMed1996

Myxoma of the mandible.

Myxoma of the jaw bone is a peculiar and rare tumor. A case of myxoma of the mandible is described in a 38-year-old man. The plain X-ray showed multiple osteolytic destructive lesions in the molar root area. CT scans demonstrated osteolytic expansile lesions with mild enhancement of the solid portion of the mass. Histologically, the tumor is composed of plump stellate cells with abundant amorphous myxoid stroma.

Adult↗
PubMed2003

Resection of the prominent mandible angle with intraoral and external approach.

Surgical resection of the prominent mandible angle is a common aesthetic procedure in Asian women. Many females want to change their square-shaped face to a round-shaped face, because the square-shaped face is, not considered attractive in Asian culture. Several approaches have been used for this procedure. Surgeons usually have used the intraoral approach because it can avoid the external scar. However, the intraoral approach can have many drawbacks due to the limited operative field and view. In particular, subcondyle fracture occurs more easily because of the limited motion of the saw. This article presents an operative method that avoids subcondyle fracture and makes the procedure easier to execute. The procedure has two main differences; one is the addition of an external stab incision to the conventional intraoral incision and the other is the use of the reciprocating saw instead of the oscillating saw. Forty-three patients were operated on and we recommend this procedure as an easier procedure with less complication than the intraoral-only approach.

Adult↗
PubMed2003

Deformation characteristics of the human mandible in low impact experiments.

A total of 11 human mandibles were subjected to physical impacts under standardised conditions. Two impact sites and directions were tested and the impact load was varied in four steps. Two occlusional strengths were applied and the influence of simulated soft tissue covering was recorded. The deformation of the bones was measured using strain gauge strips located at eight defined sites. In a series of frontal to occipital impacts the frontal areas and the collum showed the largest length changes. Increasing impact intensities led to a proportional increase of the length changes. An increase of the occlusional strength was either protective (at the collum) or it increased the deformation (frontal area). The soft tissue covering was only partly protective. Lateral impact was characterised by a compression on the side of the impact and stretching on the other side only. The intensity and speed of deformation increased with increasing distance from the site of impact. A fixed occlusion caused an increase of compression at the site of impact and an increasing stretching in the frontal part of the bone and at the opposite collum.

Adult↗
PubMed2003

Fracture properties of the human mandible.

A total of seven human mandibles were struck to breaking point under standardised conditions using a pendulum. The cortical deformation for two impact directions was measured with strain gauge strips located at eight defined sites. Fronto-median impacts led to mostly bilateral and always multiple fractures in the posterior area of the bone, especially in the collum and the condyle. The fracture threshold was between 2.5 and 3.1 kN. Lateral impact caused fractures near the impact area as direct fractures of the ipsilateral corpus. Mainly single and double fractures were observed. For lateral impact the fracture threshold was between 0.6 and 0.8 kN.

Adult↗
PubMed2001

Sexual dimorphism of the human mandible: demonstration by elliptical Fourier analysis.

A new quantitative approach of the mandibular sexual dimorphism, based on computer-aided image analysis and elliptical Fourier analysis of the mandibular outline in lateral view is presented. This method was applied to a series of 117 dentulous mandibles from 69 male and 48 female individuals native of Rhenish countries. Statistical discriminant analysis of the elliptical Fourier harmonics allowed the demonstration of a significant sexual dimorphism in 97.1% of males and 91.7% of females, i.e. in a higher proportion than in previous studies using classical metrical approaches. This original method opens interesting perspectives for increasing the accuracy of sex identification in current anthropological practice and in forensic procedures.

Female↗
PubMed2005

Architecture and mineralization of developing cortical and trabecular bone of the mandible.

Ossification of the presumptive trabecular bone in the mandibular condyle and the presumptive cortical bone in the mandibular corpus of the pig mandible was investigated during development, using micro-computed tomography (microCT). Three-dimensional architecture and mineralization characteristics were assessed from ten pigs of different developmental ages. In the condyle, increases in trabecular thickness and separation and a decrease in the trabecular number, led to an unchanged bone volume fraction. A conversion from rod-like into plate-like trabeculae was observed. Bone volume and trabecular thickness were always higher in the corpus, where an increase in bone volume fraction was caused by an increase in the trabecular thickness and a decrease in separation. A transition from a plate-like structure into a more compact structure took place. The average degree of mineralization in the condyle and the corpus increased with age. In the corpus, the degrees of mineralization were higher than in the condyle. The differences between the condyle and corpus and the changes with age could be explained by differences in the distribution of mineralization within the trabecular elements. Generally, the degrees of mineralization increased from the surface toward the centers of the trabecular elements, indicating growth of the trabecular elements by the surface apposition of new mineral.

Animals↗
PubMed2003

Epithelioid hemangioendothelioma of the mandible.

The authors describe a locally recurrent tumor of the mandible whose microscopic structure and immunohistochemical findings corresponded to an epithelioid hemangioendothelioma. The tumorous cells had an epithelioid character, they created rudimentary vascular lumina, and they focally expressed vascular markers CD 34, CD 31, and F VIII. Locally the tumor grew aggressively. During the last recurrence, the tumor even affected the already healed and rebuilt bone graft, which was incorporated after the primary resection of the mandibular body. From the histological point of view, the tumor approximated an angiosarcoma. No metastases occurred.

Aged↗
PubMed2003

[Primary implant stability with different bone surgery techniques. An in vitro study of the mandible of the minipig].

The treatment concept of osseointegration is based on a stable embodiment of implants in bone and the maintenance of stability during functional load. A goal of the surgical preparation technique is therefore to obtain a stable and firm implant anchorage. The aim of this study was to evaluate implant stability after different surgical treatment of the bony implantation bed. Thirty cylindrical solid-screw-shaped implants with standard SLA ITI configuration were implanted into the explanted mandibles of five minipigs. The implant sites were prepared either by a conventional burr technique (group A), by burr technique with additional thread cutting (group B), or by the osteotome technique (group C). Primary implant stability was evaluated by resonance frequency analysis and removal torque test. The average value of the resonance frequency analysis (RFA) was 6000+/-469 cycles/s in group A, 5700+/-557 cycles/s in group B, and 5540+/-527 cycles/s in group C. Removal torque values of group A (507+/-57 Nmm) were significantly higher than those of group B (466+/-45 Nmm) and group C (240+/-31 Nmm) (between group A and C p<0.05, group A to B p=0.39, and B to C p<0.05). It can be concluded from this study that the conventional burr technique achieves a statistically significantly better primary bone anchorage than the osteotome technique.

Animals↗
PubMed2003

[Preoperative determination of the position of mandibular canal for planning sagittal ramus osteotomy of the mandible].

BACKGROUND: In the literature the incidence of permanent nerve lesions ranges from 3 to 39%. Therefore, we think that it is necessary to discuss the procedure of individual risk assessment and management. Standard imaging techniques for the preoperative planning and preparation of a sagittal split osteotomy usually include a panoramic radiograph and lateral cephalometric radiograph. If an assessment of the transversal thickness of the lower jaw and cortical substance is required, or the position of the inferior alveolar nerve needs to be determined for preoperative planning, computed tomography of the viscerocranium has to be performed. By employing the conventional computed tomographic X-ray imaging system CommCAT, we are able to determine preoperatively both the transversal thickness of the lower jaw including the cortical substance and the diameter of the ascending ramus of the mandible at the proximal osteotomy site. PATIENTS AND METHOD: We examined prospectively the value of these additional investigations and compared them with the intraoperative findings in 29 patients. With these tomograms, the relation between the position of the inferior alveolar nerve and the vestibular cortical bone was metrically evaluated. In 17 of 58 jaw sides we detected the nerve at a distance from the outer cortical bone of 2 mm or less. The situation for the upper osteotomy was critical in eight cases where the thickness of the mandibular ramus was only 3 mm. RESULTS: By using of the conventional computed tomography system CommCAT, we have the preoperative opportunity to determine the transversal thickness of the mandibular ramus as well as the exact position of the inferior alveolar nerve and its distance from the cortical bone of the mandibular corpus. By predicting the nerve's position and its relation to the osteotomy site, we are able to individualize the operation procedure so that a high standard of safety can be achieved.

Adolescent↗
PubMed2006

[Computer assisted chewing power in patients with segmental resection of the mandible].

BACKGROUND: Surgical treatment of tumors of the oral cavity often requires a segmental resection of the mandible. This always implies a considerable loss in function and aesthetics. The aim of the present study was to measure the chewing force obtained by patients after mandibular resection. PATIENTS AND METHODS: In a group of 20 patients (twelve males, eight females, average age 59 years), chewing force were registered by means of a computerized measurement device. In 16 patients, the defect was bridged by a reconstruction plate, in three with an iliac bone graft stabilized by miniplates, and in one patient with only two miniplates. RESULTS: The maximum value in the molar region was 186 N und the minimum was 28 N. The average bite force in the molar region reached 81.1 N (+/-46.1) with 42.9 N (+/-35.7) in the front region. The highest value was registered in a patient with an iliac bone graft without soft tissue defect. The lowest was found in patients with bony chin defects. CONCLUSION: Based on these results, a reduction of 76% in the molar region and 59% in the incisor region was observed. These values might be helpful in providing a more realistic definition of the functional loadings found in patients after mandibular resection, which in turn may help in the development of new reconstruction devices.

Biomechanical Phenomena↗
PubMed2000

[Hyperbaric oxygen therapy. Clinical use in treatment of osteomyelitis, osteoradionecrosis and reconstructive surgery of the irradiated mandible].

The aim of hyperbaric oxygenation (HBO) is to increase transported oxygen in the blood over the rise of the physiologically solved part. In oral and maxillofacial surgery, treatment-resistant osteomyelitis and osteoradionecrosis are indications for HBO (according to Undersea and Hyperbaric Medical Society). Furthermore, there is an indication to apply HBO to compromised transplants of bone or soft tissue. Since 1994, 28 patients have been treated with HBO in the department of oro-, maxillofacial surgery of the Medical School Hannover. Sixteen patients had a treatment-resistant osteomyelitis. Two patients were suffering from an osteoradionecrosis in the irradiated mandible. Nine patients had received autogenous transplants, which were threatened by infection or an insufficient recipient-side. One patient was treated because of a chronic non-healing wound. In six patients we found that the chronic osteomyelitis had healed. This was proven by clinical examination and scintigraphic findings. In eight patients we had a decrease in turnover in scintigraphy and an improvement of the clinical situation. Two patients with osteoradionecrosis showed clinical improvement under HBO. In nine patients with threatened transplants we saw good healing of all critical grafts under HBO. One patient with a non-healing wound could be cured with HBO. It was shown that with HBO we could cure osteomyelitis, osteoradionecrosis and non-healing wounds to a large extent. Grafts which were threatened by infection or insufficient recipient-side healed after the application of HBO.

Adult↗