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Palaeopathological and variant conditions of the Homo heidelbergensis type specimen (Mauer, Germany).

Although early Homo specimens are now known from a number of African, Asian and European Middle Pleistocene sites, the taxon Homo heidelbergensis was initially introduced for the Mauer jaw recovered in 1907. Fossil hominids from the earlier Middle Pleistocene of Europe are very rare and the Mauer mandible is generally accepted as one of the most ancient, with an age of approximately 700 kyr. A new preparation of the mandible was conducted in 1996 and gave rise to the detailed palaeopathological examination which is presented here. Based on comparative analyses, the extreme breadth of the mandibular ramus and its flat intercondylar incision, in conjunction with the flattening and broadening of the coronoid process tip, results either from an idiosyncratic pattern of the course and insertion of the temporalis muscle on the coronoid process or from the temporalis possessing an accessory head. The incidence of periodontal pocketing, together with a vertical reduction of the alveolar margin to approximately 3.00 mm, and a slight protuberance formed in vicinity of the right M(2)can safely be interpreted as pathognomonic indications of periodontal disease. The short distance between the enamel-dentine junction of the teeth and the horizontal alveolar margins could either be an inherited variant or may result from incipient osteoporosis. In addition, an arthrotic condition with slight osteophytic peripheral exostoses and an arthrolit (i.e. an articular calculus or "joint mouse") on the left condylus articularisand a depression in the medial part of the left mandibular condyle extending into the inferior part of the ramus are present. These features are indicative of a trauma-induced osteochondrosis dissecans. The diagnosis therefore suggests that the observed depression results from a well-healed fracture. This traumatic event illustrates the demanding living conditions endured by humans during the European Middle Pleistocene. The variations and pathological conditions observed in Mauer do not question the mandible's role as type specimen for the taxon Homo heidelbergensis.

Alveolar Process↗

The colonization and establishment of invading bacteria in periodontium of ligature-treated immunosuppressed rats.

The morphologic features and pattern of bacterial invasion of the periodontal tissue in ligature-induced periodontal defects of immunosuppressed rats were studied. Silk ligatures were placed circumferentially on the maxillary left second molar of 24 Sprague-Dawley rats. The treatment group (14 rats) received Cytoxan (75 mg/kg) the day after ligature placement and at Day 4. The control group (10 rats) received no medication. All animals were sacrificed on Day 8 and the maxillae processed for light and electron microscopy. Only ligated sites in immunosuppressed animals exhibited bacterial invasion. Invading bacteria consisted of microcolonies of Gram-negative and Gram-positive coccoid cells and rods located near the tissue surface. Each microcolony consisted of morphologically homogeneous microorganisms. The deeper sites revealed a diffuse invasion of Gram-negative rods which appeared morphologically similar. Other features associated with invasion were complete destruction of epithelial tissue next to the ligature and the lack of inflammatory cells in the gingival region. These findings, when compared to those of other reports of tissue penetration by bacteria, point to the necessity of differentiating between bacterial invasion of gingival tissues, associated with penetration of tissues by proliferating bacteria, and bacterial translocation, a situation in which bacteria are passively carried into the tissues, for example by mechanical manipulation immediately before or during biopsy taking, or possibly during processing for histology.

Alveolar Process↗

Osseous coagulum: a histologic evaluation.

Chronic periodontitis can be successfully simulated in primates by the method employed in this study. Osseous defects can be created with a marked degree of similarity to one another and subsequently rendered into chronic lesions for healing-repair studies. The chronic periodontal ossious defects corrected by the osseous coagulum technique and by curettage in the rhesus monkey in this study were repaired by the regeneration of the architecture of the lost tissue. The use of the osseous coagulum in two- and three-walled periodontal osseous defects led to a more rapid osteogenesis in such defects as compared to correction by curettage alone. This rapid filling of the osseous defects may serve to inhibit the apical migration of the epithelial attachment during the early stages of repair, and thereby inhibit a subsequent recurrence of the defect. Clinically and histologically, no readily apparent distinction could be made in the healing process between the two- and three-walled lesions.

Alveolar Process↗

Digital image processing of crystalline specimens examined by electron microscopy.

Crystalline specimens imaged in the electron microscope are analysed using digital processing. Some principles of structural analysis using the method of Fourier decomposition are discussed. Complementary techniques, such as enhancement by gradient and Laplacian operators, have been found useful in analysing electron micrographs. The application of these techniques to some problems in Materials Science and Biology are reviewed. By selecting and phase-correcting spots in the computed diffraction pattern, it was possible to localize atoms, molecules, and their defective arrangement in evaporated gold, sputter-deposited tungsten films, and single crystals of cadmium selenide. Digital processing based on the theory of helical diffraction was used to explore the three-dimensional arrangement of molecules in cellular components of alveolar soft part sarcoma, Hirano bodies, and neurofibrillar tangles in the human brain.

Actins↗

Peridontal manifestations and treatment in a case of Sturge-Weber syndrome.

A case of Sturge-Weber syndrome, uncommon in its intraoral extent, is presented. The pathologic process involved both the soft and osseous tissues of both the maxilla and mandible of the affected side. The first known histopathologic description of alveolar bone involvement is presented. The patients was treated by means of extractions and periodontal flap surgery on both an outpatient and an inpatient basis, with good results and no untoward sequelae. common clinical findings in Sturge-Weber syndrome and specific signs and symptoms manifested by this patient are discussed.

Adult↗

Chronic sclerosing osteomyelitis: treatment considerations in an atypical case.

Chronic sclerosing osteomyelitis has been frequently described in the literature but little has been recommended for the management of the resistant cases that fail to respond to conservative treatment. This report describes the long term management of a particularly aggressive case of CSO and indicates maxillary sinus disease as a possible etiologic factor in CSO of the maxillary alveolus. Treatment required in more extensive cases must be as aggressive as dictated by the entire disease process and the total medical evaluation.

Adult↗

[The relationship of the mechanical properties of the dentoalveolar complex to the status of the bone tissue in traumatic occlusion].

The authors have developed a model of traumatic occlusion, simulating a swinging functioning overload of the periodontium in dogs; this model is adequate to the clinical conditions of occlusion disorders of dentitions. Experiments with 18 dogs have demonstrated a relationship between change in the biomechanical and physical properties of dentoalveolar tissues and the length of traumatic occlusion. Experiments have shown a progressive reduction of the ability of dental abutment tissues to resist the load and slowed down reparative processes in the periodontal tissues in swinging type traumatic occlusion.

Alveolar Process↗

The finite element method: a tool to study orthodontic tooth movement.

Orthodontic tooth movement is achieved by (re)modeling processes of the alveolar bone, which are triggered by changes in the stress/strain distribution in the periodontium. In the past, the finite element (FE) method has been used to describe the stressed situation within the periodontal ligament (PDL) and surrounding alveolar bone. The present study sought to determine the impact of the modeling process on the outcome from FE analyses and to relate these findings to the current theories on orthodontic tooth movement. In a series of FE analyses simulating teeth subjected to orthodontic loading, the influence of geometry/morphology, material properties, and boundary conditions was evaluated. The accurate description of alveolar bone morphology and the assignment of non-linear mechanical properties for the PDF elements demonstrate that loading of the periodontium cannot be explained in simple terms of compression and tension along the loading direction. Tension in the alveolar bone was far more predominant than compression.

Alveolar Process↗

[Bone resorption in orthodontic tooth movement: an attempted schematization].

The osteoclast is the major cellular agent of bone resorption. Hormonal stimulation of bone resorption is indirect and depends on the osteoblastic function. Protease production is the final common pathway through which osteoblastic cells initiate osteoclastic resorption. Exposition of the mineralised matrix and contact with the osteoclasts always comes before resorption, regardless of the stimulating agent involved in the resorption process. In orthodontic conditions, production and activation of osteoclasts may be attained through different ways. Inflammation subsequent to tissue damage and bioelectric perturbations associated to alveolar bending can be considered as two major events which may lead to increase bone resorption and orthodontic tooth displacement. The precise transduction mechanism of an orthodontic force into cellular resorbing activity is still obscure.

Alveolar Process↗

Effects of Stachybotrys chartarum (atra) conidia and isolated toxin on lung surfactant production and homeostasis.

This study evaluated the effects of Stachybotrys chartarum conidia and a trichothecene, isosatratoxin-F, on choline incorporation into DSPC by fetal rabbit alveolar type II cells and on alveolar surfactant subtypes in mice. Exposure of fetal rabbit type II cells to S. chartarum conidia at concentrations of 10(3) to 10(6) conidia ml(-1) significantly depressed [3H] choline incorporation after 24 h of exposure. Exposure of the rabbit cells to 10(5) to 10(6) conidia ml(-1) also resulted in significantly depressed [3H] choline uptake after 48 h. Additionally, fetal rabbit alveolar type II cells exposed to isosatratoxin-F in concentrations ranging from 10(-9) to 10(-4) M showed a significant reduction in [3H] choline incorporation into DSPC. Alveolar surfactant phospholipid concentrations in the different metabolic subfractions of lung lavage fluid of mice intratracheally exposed to either 50 microl of 10(7) ml(-1) S. chartarum conidia or 50 microl 10(-7) M isosatratoxin-F showed some significant changes at 12, 24, 48, and 72 h post-exposure, compared to the surfactant subfractions of control mice which were either untreated, exposed to saline or to 50 microl of 10(-7) ml(-1) Cladosporium cladosporioides conidia. In both the S. chartarum- and the isosatratoxin-F-treated mice, exposure significantly increased P10, P100, and S100 phospholipid concentrations, while the P60 phospholipid concentrations were depressed. In contrast, C. cladosporioides-treated mice showed only one significant change in subfraction phospholipid concentration: P60 was depressed at 48 h post-exposure. These results reveal that alveolar type II cells are sensitive to exposure to S. chartarum conidia and to isosatratoxin F. Sensitivity is manifest by alterations in the normal metabolic processing of alveolar surfactant. In exposed mice, this effect appears to involve a significant increase in newly secreted surfactant and an accumulation of the used surfactant forms.

Analysis of Variance↗