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At least 1,117 records · Page 62Linked to original sources
PubMed2004

Bone mineral content of the mandible and spine in ovariectomized rats with estrogen deficiency.

The aim of this study was to assess the bone mineral content of the mandible and spine in rats with estrogen deficiency after ovariectomy. Female rats were divided into the following groups: CL--control, SH--sham-operated, OV--after ovariectomy, OVH--after ovariectomy receiving 17beta-estradiol in three different doses (1.25, 12.5, 125 microg) during seven weeks. After the experiment densitometric examinations of the mandible and spine were made using DEXA method and there was measured bone mineral content (BMC). The results of the examination indicate that estrogen deficiency after ovariectomy leads to decreasing of BMC index of the examined bones, and densitometric examinations allow to carefully evaluate changes in the mineral part of the examined bones.

Animals↗
PubMed1992

The position of mandibular and mental foramina in Kenyan African mandibles.

Analysis of 79 adult African mandibles indicated that 64.6% of the mandibular foramina were located below the level of the posterior extension of the occlusal plane while 30.7% were located along this plane. 56.1% of the mental foramina were located below the second premolar while 31.1% were between the second premolar and first molar. The remainder were located between the premolars. The mental foramen opened posterosuperiorly in 72.5% of the surfaces. Multiple mental foramina were found on 4.5% of the mandibles. While emphasising the importance of palpation prior to administration of mental nerve block, these observations suggest that in case of uneffective mandibular nerve block, for a significant proportion of Kenyan Bantus, attempts to place the anaesthetic solution slightly below the occlusal plane be considered.

Adult↗
PubMed2006

[Clinical experience of treatment of 275 mandible fractures].

OBJECTIVE: To evaluate the treatment effect of mandible fractures. METHODS: Clinical data of 275 mandibular fracture patients of Tongchuan people's hospital were analysed. RESULTS: (1) The systemic health of 27 non-surgery cases were influenced during the intermaxillary ligation and 3 cases of them had deformity of maxillofacial region. (2) In the surgery group, 5 of 73 cases fixed by steel wire had disorder of occlusion, 6 of 169 cases fixed by titanium mini plate accepted secondary operation of removing the plates, and 6 cases fixed by bioabsorbable mini plate had better effect. CONCLUSION: The internal rigid fixation is an appropriate and effective method for the mandible fractures.

Bone Plates↗
PubMedDate not supplied

Preliminary report on a staged ridge splitting technique for implant placement in the mandible: a technical note.

PURPOSE: Narrow edentulous alveolar ridges less than 5 mm wide require horizontal augmentation for the placement of screw-type dental implants. A staged approach to ridge splitting in the mandible to decrease the risk of malfracture during osteotomy is presented. MATERIALS AND METHODS: Five consecutive patients with 6 long-span edentulous areas of the mandibular ridge were included in this study. After corticotomy of a rectangular buccal segment and a 40-day healing period, the mandibular ridge was split, leaving the buccal periosteum attached to the lateralized segment. Seventeen dental implants were placed, and the gap between the implants and the bone filled with a mixture of venous blood and a porous algae-derived hydroxyapatite. RESULTS: All buccal segments fractured as planned at the basal corticotomy during ridge splitting. After 6 months, all implants were stable and surrounded by bone; prosthetic loading with fixed partial dentures was successful in all cases. DISCUSSION: In the mandible, greenstick fracture during widening with osteotomes has not been controllable to date because of cortical thickness of the bone; the risk of malfracture during single-stage ridge splitting was high. With this approach, the location of the greenstick fracture is predetermined, and the perfusion for the buccal segment remains intact, although vascularization shifts from internal perfusion from spongy bone after the first intervention to external perfusion from the periosteum after the second intervention. The buccal cortical segment remains a pedicled graft after ridge splitting. CONCLUSION: The preliminary results of this report indicate that staged ridge splitting can be a safe technique which overcomes the problems associated with single-stage ridge expansion/ridge splitting procedures without causing significant delay in treatment.

Adolescent↗
PubMed2006

Development of a static and dynamic simulator for osteosyntheses of the mandible.

The development of new methods and materials for osteosynthesis requires in vitro testing prior to clinical use to exclude major problems or difficulties. In the field of oral and maxillofacial surgery no standardized testing procedures have so far been established. From a biomechanical point of view the lower jaw can be described as a lever that during the chewing cycle various forces at various points of the bone act upon. Standardized solid foam polyurethane mandibles (Sawbones, Malmö, Sweden) were used for the testing of various types of screws and different types of fractures. Via linkages that were connected to hydraulic cylinders defined forces were exerted on the polyurethane mandibles and the deformation was registered depending on the force. Monitoring was carried out contactless and therefore without back coupling by the use of a video system that recorded well-defined points on both sides of the fracture line. The photographs were then evaluated by special software (SIMI MOTION CAPTURE). The control of the cylinders was performed through a processor that besides static forces also allowed dynamic testing (e.g. sinusoid oscillation with defined amplitude and number of cycles). For the standardized and realistic three-dimensional static or dynamic testing of new methods and materials for osteosynthesis of the lower jaw this test stand has proved to be optimally suitable. Independent on the type of fracture and the material used the field of application for our test stand is the complete lower jaw. Therefore an ethically correct and economically reasonable testing of industrial products and clinical methods of osteosynthesis can be performed with this simulator.

Absorbable Implants↗
PubMedDate not supplied

Impact of experimental trauma and niflumic acid administration on antimicrobials' concentration in serum and mandible of rats.

Administration of antibiotics and analgesics in surgery or trauma is of great importance for an effective treatment. Trauma, as stress stimulus, causes alterations in various functions of the organism as well as in drug pharmacokinetics. The aim of this study was to determine the effect of trauma upon the serum and bone levels of the antimicrobial ampicillin and cefapirin, with and without co-administration of a non-steroidal anti-inflammatory analgesic (NSAIDs). Fifty-six male Wistar rats were divided into two groups A (control) and B (experimental). Each group consisted of 4 subgroups (n=7) receiving ampicillin, ampicillin with niflunic acid, cefapirin, and cefapirin with niflunic acid. In group B traumatic injury was performed by incision (7 mm length) in the right cheek. The levels of the antibiotics were estimated by the inhibition zone of B. subtilis. An increase in antibiotic levels was observed in group B, being statistically significant only for cefapirin level in the mandible. Upon niflumic acid co-administration a statistically significant rise in serum ampicillin and mandible cefapirin levels was observed in both control and experimental groups (student t-test). It can be concluded that the combination of antibiotics and non-steroid antiinflammatory drugs (NSAIDs) may enhance the antibacterial drug concentration.

Ampicillin↗
PubMedDate not supplied

A quantitative genetic analysis of localized morphology in mandibles of inbred mice using finite element scaling analysis.

We analyzed patterns of mandibular genetic and phenotypic morphological integration and the relationship of genealogy to interstrain molecular and morphological differences in ten inbred strains of mice. Positions of mandibular landmarks in two-dimensional space were used to construct a finite element mesh for each individual, then all individuals from the ten strains were compared to the average mandible from a standard strain (SEA/GnJ). Measures of size and shape associated with finite element scaling analysis were then used in a quantitative genetic analysis of mandibular variation. Significant genetic variation for mandibular size and shape was uncovered. Patterns of both genetic and phenotypic correlation for measures of landmark-specific sizes were consistent with models of morphological integration based on the developmental origin of parts of the mandible and on the effects of muscle attachment on mandibular morphology. Shape differences local to particular landmarks did not show these forms of morphological integration. Although interstrain distances based on local shape magnitudes were significantly correlated with genealogical relationship, distances based on local size differences were not. Even higher than the correlation of genealogy with distances based on local shape magnitude was the genealogical-molecular distance correlation. Patterns of morphometric mandibular variation corresponded to expected effects of epigenetic developmental processes. Also, when detailed shape differences were considered, morphology served as a rough guide to genealogy, although molecular distances showed a stronger relationship.

Animals↗
PubMed1991

Cortical thickness in human mandibles: clinical relevance to the sagittal split ramus osteotomy.

Human cadaver hemimandibles were subjected to sagittal split ramus osteotomy, and the cortical thickness of each mandible was then measured in several areas. A measurable difference in morphology was found in the proximal segment of the mandible. Because cortical bone thickness is directly related to bone-screw holding strength, these results have important implications for the use of rigid internal fixation. The results suggested that the areas that coincide with the most anterior and superior extent of the osteotomy would be the ideal locations for screw placement.

Adult↗
PubMed1991

Osseo-integration of dental implants in radiated mandibles: an experimental study with beagle dogs.

This investigation was planned to detect the ability of radiated bone to integrate with dental implants and to study the load-bearing capacity of these implants. In five beagle dogs, the premolars were extracted, after which one side of the mandible was radiated with 40 Gy. Three months later, two hollow-cylinder implants were placed on each side of the mandible. After a three-month period of osseo-integration, bridges were constructed on the implants, and they were loaded for six months. Both clinical and x-ray examinations showed that all implants had integrated well and bore load without change in their host sites for a six-month period, at which time the dogs were killed.

Animals↗
PubMed1991

Alloplastic augmentation of the anterior mandible.

Alloplastic implantation of the anterior mandible--and when indicated, the posterior mandible--is not only a surgical technique but also a carefully and meticulously learned art form. The day of stuffing preformed and poorly thought out commercial implants into a chin without consideration of host contour is hopefully behind us. During the decade of the 1990s and in subsequent years, the demand will continue to be for a carefully conceived, carefully prepared, and exactly executed repair of mandibular contour defects. The availability of new implant designs makes this actualization a simpler task. Familiarity with osteoplastic techniques and orthodontic possibilities, constraints, and processes allows the aesthetic surgeon to select properly those cases for which alloplastic implantation offers the best solution to the existing problem.

Humans↗
PubMedDate not supplied

[Position of the mandibular foramen in relation to the width of the ramus and the gonial angle of the mandible].

The aim of this study was to investigate the position of the mandibular foramen in relation to the width of the ramus and the gonial angle of the mandible. One hundred fourty-two dry human mandibles of adults were used. It was found that only the size of the gonial angle affects the anterioposterior position of the foramen. We didn't observe any relation between the inferior-superior position of the foramen and the above parameters.

Adult↗
PubMed1990

[Research of condylar movement on nonworking side during quantitative lateral movement of mandible].

Cephalometric laminagraphs were taken on 40 left and right sides of 20 adults with normal occlusion. It was found that condyle of nonworking side during quantitative lateral movement at incisal region with 1mm interval up to 3mm. The results were analyzed by computer superposition graph. The results were as follows: 1. The displacement of condyle during quantitative lateral movement of the mandible was 1.00mm, 1.93mm and 2.88mm at condylar top from intercuspal position to a maximum 3mm, 1mm by 1mm average, respectively. The displacement at condylar center was 0.97mm, 1.92mm and 2.85mm average, respectively. It was noticed that condyle on nonworking side with lateral movement translated equal distances. 2. The inclination of condyle by the quantitative lateral movement of the mandible was 45.41 degrees, 49.13 degrees and 48.59 degrees at condylar top from intercuspal position to a maximum 3mm, 1mm by 1mm average, respectively. The inclination at condylar center was 44.21 degrees, 48.06 degrees and 48.44 degrees average, respectively. Directional stabilizing with condylar movement, was seen. 3. The range of condylar movement from intercuspal position, at condylar center was maximum; 40.1 degrees, minimum; 0.0 degrees, average; 10.05 degrees, SD; 7.98 degrees. 4. The results of the survey on rotation factor with condylar movement revealed that there was a slight difference, and the movement of condyle was like bodily shift.

Adult↗
PubMed1990

[Relationship between late adolescent growth of mandible and maturity indicators--mandibular third molar, hand bones, body height--in Japanese boys].

The study was undertaken to investigate the individual growth timing of the mandible during late adolescent period. Materials used in this study were lateral cephalometric X-rays, hand bones X-rays, panorama X-rays and data of standing height of eighteen Skeletal Class I Japanese boys, all were longitudinally taken from 15 to 18 years old. Results were as follows: 1. Mandibular growth was continued to increase until 18 years old, but annual growth rate was decreased every year. 2. Growth increments of mandibular length was widely varied during 15 to 18 years old. 3. Ossification timing of MP3u and R-IJ stage were tended to delay in cases, represented large amount of growth. 4. Cases showing large amount of growth in the mandible tended to have large increments in body height. 5. There was less correlation between mandibular growth timing and maturation of lower third molars. In conclusion, the growth behavior of hand bones and body height could be used as indicators for predicting mandibular growth potentiality during late adolescent period.

Adolescent↗
PubMed1990

[Classification of edentulous mandibles in preventive implantology].

The aim of preventive implantology is to prevent or delay the resorption of edentulous alveolar ridges. The classifications of the resorption stages of the mandible which are now in use, are not applicable to preventive implantology. After anatomic research it was concluded that the resorption of the alveolar ridge of the mandible should be classified in three stages. Loaded as well as unloaded implants can function as tooth root analogues in maintaining the volume of the edentulous ridge.

Alveolar Bone Loss↗
PubMed1990

A precise radiographic method to determine the location of the inferior alveolar canal in the posterior edentulous mandible: implications for dental implants. Part 2: Clinical application.

An analysis of implant placement in the posterior region of eight edentulous cadaver mandibles was performed. The results demonstrated that the radiographic technique developed can be employed to safely place implants adjacent to the inferior alveolar nerve in the posterior mandible by using radiographic laminography and a specially designed intraoral reference splint.

Adult↗
PubMed1989

[Validation of the concept of morphofunctional unity of the structural components of the human mandible].

Interconnections of the mandibular macro- and microsigns have been studied in 98 corpses of men. By means of the multidimensional analysis discreteness and autonomy of the mandibular structural components are revealed; this demonstrates that there is a possibility of an active arrangement of parts and structural components of the mandible depending on the external environmental conditions in order to reach optimal terminal functional effect--chewing. The most discriminative signs of contrasting variants in the structure of the mandible are revealed.

Adaptation, Physiological↗
PubMed1989

[Individual growth study of the effects of chin cap force to the mandible].

This study was undertaken to investigate a certain regulation of the chin cap force to a growing human mandible, especially with regard to the effect on the growth amount and timing by means of allometric relation between stature and craniofacial complex. Materials were consisted of roentgencephalograms which had been taken from fifteen Japanese females with skeletal class III malocclusion and records of time length of chin cap use and stature. The results were as follows: 1. Chin cap had a great influence on mandible during the preadolescent and adolescent periods (P less than 0.01). 2. What was most influenced by orthopedic force was intercondylar width, followed by mandibular length, intergonial width, mandibular body length, and ramus height. 3. Restraint of growth was found in mandibular length, mandibular body length, and ramus height, but on the other hand acceleration of growth in intercondylar width and intergonial width was also found. In conclusion, it would be possible to say that if it is used propertly, chin cap therapy can be effective within certain limits for skeletal class III malocclusions in view of restraint and acceleration of mandibular growth.

Cephalometry↗