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Subcellular co-localization and co-variations of two vitamin D-dependent proteins in rat ameloblasts.

The immunocytochemical patterns of calbindin-D9k (CaBP 9k) and calbindin-D28k (CaBP 28k) were compared by light and electron microscopy throughout amelogenesis. Labelling on serial sections and co-localization of CaBPs confirmed that the two proteins were restricted to a single cell type, the ameloblasts. Their quantity increased during presecretion, was stable during secretion and alternately high and low during the cyclic modulation of ameloblasts which occurs during maturation. Ruffle-ended ameloblasts contained the highest apparent concentration. Investigations with several fixatives indicated that the CaBPs were present in the cytosol and the nucleus, although there were slight differences with various fixatives by light microscopy. Their concentrations in these compartments varied in parallel throughout amelogenesis. However, mitochondria contained only immunoreactive CaBP 9k. While the distribution of CaBP 9k in zones containing Golgi apparatus and rough endoplasmic reticulum was similar, CaBP 28k concentration has, in another paper, been shown to be higher near the rough endoplasmic reticulum.

Amelogenesis↗

Histologic evaluation of human intrabony defects following non-surgical periodontal therapy with and without application of an enamel matrix protein derivative.

BACKGROUND: Surgical periodontal treatment with enamel matrix protein derivative (EMD) has been shown to promote periodontal regeneration. However, it is not known whether nonsurgical periodontal therapy with additional subgingival application of EMD may also enhance periodontal regeneration. The purpose of this study was to clinically and histologically evaluate healing of human intrabony defects following non-surgical periodontal treatment with and without application of EMD. METHODS: Sixteen patients, each of whom displayed one advanced intrabony defect around teeth or roots scheduled for extraction, were included in the study. The defects were treated as follows: 1) scaling and root planing with hand instruments and application of EMD; 2) scaling with an ultrasonic instrument and application of EMD; or 3) scaling with an ultrasonic instrument alone. Healing was uneventful in all cases. Six months after surgery, the teeth or roots were extracted together with some of their surrounding soft and hard tissues and processed for histologic evaluation. RESULTS: Clinical examination revealed a probing depth reduction and a gain of clinical attachment after all 3 treatment modalities. The histological evaluation, however, revealed that healing in all 3 procedures was predominantly characterized by formation of a long junctional epithelium along the instrumented root surface and no predictable regeneration of attachment apparatus. CONCLUSION: Within its limits, the present study failed to show periodontal regeneration in advanced human intrabony defects following non-surgical treatment with subgingival application of EMD.

Alveolar Bone Loss↗

Cytokeratins in epithelia of odontogenic neoplasms.

Neoplasms and tumours related to the odontogenic apparatus may be composed only of epithelial tissue or epithelial tissue associated with odontogenic ectomesenchyme. The immunohistochemical detection of different cytokeratins (CKs) polypeptides and vimentin has made it easier to explain the histogenesis of many epithelial diseases. The present study aimed to describe the immunohistochemical expression of cytokeratins 7, 8, 10, 13, 14, 18, 19 and vimentin in the epithelial components of the dental germ and of five types of odontogenic tumours. The results were compared and histogenesis discussed. All cells of the dental germ were positive for CK14, except for the preameloblasts and secreting ameloblasts, in which CK14 was gradually replaced by CK19. CK7 was especially expressed in the cells of the Hertwig root sheath and the stellate reticulum. The dental lamina was the only structure to express CK13. The reduced epithelium of the enamel organ contained CK14 and occasionally CK13. Cells similar to the stellate reticulum, present in the ameloblastoma and in the ameloblastic fibroma, were positive for CK13, which indicates a nature other than that of the stellate reticulum of the normal dental germ. The expression of CK14 and the ultrastructural aspects of the adenomatoid odontogenic tumour probably indicated its origin in the reduced dental epithelium. Calcifying odontogenic epithelial tumour is thought to be composed of primordial cells due to the expression of vimentin. Odontomas exhibited an immunohistochemical profile similar to that of the dental germ. In conclusion, the typical IF of odontogenic epithelium was CK14, while CK8, 10 and 18 were absent. Cytokeratins 13 and 19 labelled squamous differentiation or epithelial cells near the surface epithelium, and CK7 had variable expression.

Ameloblastoma↗

[The value of functional analyses for systematic periodontal treatment (clinical study)].

The relationship between periodontal disease and dysfunction of the stomatognathic system was examined with the usual analysis of function in the context of a clinical study. In addition to neuromuscular incoordination, premature centric contacts deflect the mandible from a muscularly stable contact position and traumatize the periodontium mechanically. After suitable treatment, the causes of functional damage to the tooth attachment apparatus may be demonstrated in connection with an exact clinical registration of the findings by a simple instrumental analysis of function. This analysis may be adequately carried out with a semiadjustable articulator together with a rapidly transmitted curve.

Dental Articulators↗

Tubes, lines, catheters, and other interesting devices.

Medical devices (tubes, catheters, lines, prostheses, etc.) are a common finding on radiologic studies. Sometimes they may be misdiagnosed as a pathologic process, or an important observation concerning a medical device may be overlooked because of lack of familiarity with a particular device. This review discusses a variety of tubes, lines, catheters, and other interesting and important medical devices found on everyday radiologic studies. Whenever an unusual radiologic finding is encountered, the first question to be asked is, "Is the finding a film artifact or an artifact of the imaging modality itself (computed radiography, computed tomography [CT], ultrasound, magnetic resonance imaging [MRI], nuclear medicine)? If not, does it represent a medical device or foreign material in or on the patient?" All those who interpret radiologic studies should develop the good habits of obtaining and reviewing the patient's prior studies and should, in addition, read the prior radiology reports. Good reading habits, combined with a knowledge of imaging artifacts, medical devices, foreign bodies, and normal anatomic variants, provide a solid starting point for the interpretation of radiologic studies. One very important factor often not appreciated by radiologists and referring physicians is that, in many instances, the radiologic visibility of a medical device has been given no thought, and the device has been designed with no input from the radiologic community. To compound this problem further, devices are often purchased by a hospital or medical center for the lowest price. Those purchasing devices frequently fail to seek advice from radiologists and other physicians concerning the radiologic detectability of the devices they purchase. Medical devices are manufactured from a variety of substances known as biomaterials. These include various types of metals, polymers, rubbers, ceramics, and composites. Biomaterials are substances brought into contact with living tissue for the purpose of treating a medical or dental problem. They must be compatible with human tissues chemically, mechanically, and pharmacologically. There are many ways to classify biomaterials, such as synthetic versus "natural," permanent versus transient, liquid versus solid, hard versus soft, and so forth. Although most life-support devices are within the patient's heart, blood vessels, lungs, or pleura, miscellaneous tubing, clamps, syringes, electrocardiograph (ECG) leads, and other apparatus often lie on or under the patient and appear on radiographs, especially chest studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Biocompatible Materials↗

Evolutionary relationships of Fusobacterium nucleatum based on phylogenetic analysis and comparative genomics.

BACKGROUND: The phylogenetic position and evolutionary relationships of Fusobacteria remain uncertain. Especially intriguing is their relatedness to low G+C Gram positive bacteria (Firmicutes) by ribosomal molecular phylogenies, but their possession of a typical gram negative outer membrane. Taking advantage of the recent completion of the Fusobacterium nucleatum genome sequence we have examined the evolutionary relationships of Fusobacterium genes by phylogenetic analysis and comparative genomics tools. RESULTS: The data indicate that Fusobacterium has a core genome of a very different nature to other bacterial lineages, and branches out at the base of Firmicutes. However, depending on the method used, 35-56% of Fusobacterium genes appear to have a xenologous origin from bacteroidetes, proteobacteria, spirochaetes and the Firmicutes themselves. A high number of hypothetical ORFs with unusual codon usage and short lengths were found and hypothesized to be remnants of transferred genes that were discarded. Some proteins and operons are also hypothesized to be of mixed ancestry. A large portion of the Gram-negative cell wall-related genes seems to have been transferred from proteobacteria. CONCLUSIONS: Many instances of similarity to other inhabitants of the dental plaque that have been sequenced were found. This suggests that the close physical contact found in this environment might facilitate horizontal gene transfer, supporting the idea of niche-specific gene pools. We hypothesize that at a point in time, probably associated to the rise of mammals, a strong selective pressure might have existed for a cell with a Clostridia-like metabolic apparatus but with the adhesive and immune camouflage features of Proteobacteria.

Bacterial Proteins↗

[A clinical analysis of a group of Down's patients].

The authors report their experience of the clinical analysis of 40 handicapped subjects: 28 suffered from various degrees of mental handicap and 12 had Down's syndrome. In particular, the authors focused their attention on anomalies of the stomatognathic apparatus in Down subjects, and examined and compared all those factors which are normally attributed to this pathology. An analysis of these findings shows a heterogeneity of clinical conditions which is not revealed in the literature. In the light of these new experiences, before applying pre-programmed protocols in Down's patients it is important to carry out a careful control of their dental, muscular and functional situation together with the prospects for growth and development.

Adult↗

Variations of Le Fort II osteotomies for correction of midfacial deformities.

For the correction of the retruded midface and simultaneous correction of the occlusion, 3 different types of osteotomies are presented. All 3 procedures are related to the originally described Le Fort II fracture lines. Whereas the anterior and pyramidal Le Fort II type osteotomies are only indicated in very special and rare deformities, the quadrangular type can be applied more widely. Technical details as well as possible complications are discussed. Damage to the lacrimal apparatus and the infraorbital nerve can be avoided when these structures infraorbital nerve can be avoided when these structures are handled are fully. Relapse, however, is still the main concern, particularly in the quadrangular type osteotomy. Overcorrection is therefore recommended.

Dental Occlusion↗

Crown lengthening: a surgical flap approach.

In many instances it is not possible to place a restoration margin without encroaching on the periodontal attachment apparatus. A surgical crown-lengthening procedure can provide a good solution to this common clinical problem. This article discusses indication and contraindication for surgical crown-lengthening procedures and presents an appropriate surgical technique.

Contraindications↗

[Prosthetic rehabilitation of cleft palate patients with fixed partial dentures].

Treatment of cleft palate patients demands a well coordinated work of medical and dental specialists. In spite of the surgical and orthodontic therapy a prosthetic rehabilitation is often necessary because of missing teeth, maxillary hypoplasia, malocclusion and palatal defects. The prosthetic phase begins immediately after the orthodontic treatment. In this way the fixed partial denture replaces the retention appliance and stabilizes the achieved status. The aim of the prosthetic treatment is to improve the function of the masticatory apparatus, speech and aesthetic appearance of the patient. An important task of the prostheses is to support and lift up the upper lip and the base of the nose. There are several factors, which make the treatment difficult, like underdeveloped and collapsed maxillary arch, retrognath position of the maxilla, missing alveolar ridge, defects of the bone and mucosa, scars and stiffness of the upper lip. The maintenance of the oral hygiene with the fixed restorations is often difficult because of the stiffness of the upper lip, therefore the design of the pontic is very important especially in the cases, when the missing processus alveolaris has to be replaced in order to improve the harmony of the face.

Adolescent↗

A new method for stabilization of periodontally involved teeth.

An approach is presented for the construction of an extracoronal temporary splint that meets the demands of stabilization in the presence of a compromised attachment apparatus. It is completely reversible and esthetically acceptable. It also combines the versatility of two often used materials--orthodontic grid material (for bracket placement) and self-polymerizing resins and composites, giving the combined effect of strength, stability and esthetics.

Acid Etching, Dental↗

[The distal transposition of the premolars and molars in the adult maxilla].

Clinical examinations of 100 patients and analysis of the diagnostic models of their jaws and teleroentgenograms of the head profiles (a total of 63 parameters were analyzed in 73 subjects) have revealed that distal transposition of the maxillary lateral teeth is indicated in their unilateral mesial transposition. There should be enough space for the teeth on the other side of the jaw in this case, and the median line between the central incisors should not be displaced from the center. An apparatus to carry out such transposition is suggested. The teeth were moved as far as 2 to 7.5 mm within 2.5-7.5 months. The late results are good.

Adolescent↗

Relative kinetic frictional forces between sintered stainless steel brackets and orthodontic wires.

The level of kinetic frictional forces generated during in vitro translation at the bracket-wire interface were measured for two sintered stainless steel brackets as a function of two slot sizes, four wire alloys, and five to eight wire sizes. The two types of sintered stainless steel brackets were tested in both 0.018-inch and 0.022-inch slots. Wires of four different alloy types, stainless steel (SS), cobalt chromium (Co-Cr), nickel-titanium (Ni-Ti), and beta-titanium (beta-Ti), were tested. There were five wire sizes for the 0.018-inch slot and eight wire sizes for the 0.022-inch slot. The wires were ligated into the brackets with elastomeric ligatures. Bracket movement along the wire was implemented by means of a mechanical testing instrument, and time dependent frictional forces were measured by a load cell and plotted on an X-Y recorder. For most wire sizes, lower frictional forces were generated with the SS of Co-Cr wires than with the beta-Ti or Ni-Ti wires. Increase in wire size generally resulted in increased bracket-wire friction. There were no significant differences between manufacturer for the sintered stainless steel brackets. The levels of frictional force in 0.018-inch brackets ranged from a low of 46 gm with 0.016-inch Co-Cr wire to a high of 157 gm with 0.016 x 0.025-inch beta-Ti wire. In comparing the data from a previous study by Kapila et al. 1990 performed at OUHSC with the same apparatus, the friction of sintered stainless steel brackets was approximately 40% to 45% less than the friction of the conventional stainless steel brackets.

Analysis of Variance↗

Healing following implantation of periodontitis affected roots into bone tissue.

The aim of the present experiment was to study whether new connective tissue attachment can occur to root surfaces which have been exposed to the oral environment and subsequently implanted into bone tissue. Twelve teeth in three beagle dogs were subjected to progressive periodontal breakdown to half the root length by placing cotton floss ligatures around the neck of the teeth. Following crown resection and root hemisection, the teeth were root filled and the roots thoroughly scaled and planed. Each root was extracted and implanted into bone cavities prepared in edentolous areas of the jaws in such a way that epithelial migration into the wound and bacterial infection were prevented during healing. Root implantation and sacrifice of the animals were scheduled to allow for observation periods of 1, 2 and 3 months. The results demonstrated that new connective tissue attachment did not occur to root surfaces which had been exposed to the oral environment, but healing was characterized by repair phenomena, i.e. mainly root resorption and ankylosis. In those areas of the roots where periodontal ligament tissue was preserved following tooth extraction, a functionally oriented attachment apparatus was reformed. The results indicate that in addition to apical migration of junctional epithelium and regrowth of subgingival plaque, the type of cells which repopulate the wound area may jeopardize new connective tissue attachment.

Animals↗

Synthesis and secretion of collagen by cells of connective tissue, bone, and dentin.

The production of type I collagen by fibroblasts, odontoblasts, and osteoblasts is reviewed on the basis of results obtained by electron microscopy, 3H-proline radioautography, and immunostaining for type I procollagen. In the three cell types, the precursors of type I collagen are processed along the rough endoplasmic reticulum (rER)-Golgi-secretory granule pathway in the same manner as secretory proteins, but the available evidence suggests a few special features: 1) From the rER site of synthesis, the initial collagen precursors, known as pro-alpha chains, are transported to the Golgi apparatus within tubular structures, referred to as intermediate tubules, rather than within vesicles. 2) The pro-alpha chains coil into a triple helix within spherical distensions present along the saccules on the cis side of Golgi stacks. 3) The resulting procollagens are fairly rigid and form bundles that cause spherical distensions to lengthen into cylindrical ones, whereas by an unknown mechanism these distensions become part of the saccules on the trans-side of Golgi stacks. 4) The procollagen-containing cylindrical distensions are released from trans-saccules to become secretory granules, and some procollagen material finds its way into lysosomes. 5) The secretory granules release their procollagen content by exocytosis at the cell surface. 6) The released procollagen is transformed into collagen before or, more probably, after associating with the surface of a collagen fibril.

Animals↗

[Fracture induced constriction treated by Continuous Passive Motion (CPM)].

Aspects of the history of treatment of painful joints are commented upon. It is pointed out, that the medical and dental professions have for more than 125 years been aware, that immobilization of joints may have harmful effects. Still, research on therapeutic motion of painful joints dates back only 25 years. A case is reported of fracture associated constriction, possibly due to secondary involvement of the temporalis muscle and especially its tendineous insertion on the muscular process of the mandible. When the patient was treated with the CPM apparatus Mobilimb J1 the interincisal distance increased from 13 mm to 46 mm. According to literature CPM has so far been used only as adjunctive physical therapy after surgical intervention. On the basis of data in the literature the author is studying the effect of CPM on reduced mobility of the jaws as primary treatment without surgery.

Contracture↗

[Treatment of mandibular fractures in children. Our therapeutic approach (author's transl)].

This is a study of 15 fractures of the mandible in children. We were able to make the following conclusions: --the usual causes of these fractures are road traffic accidents or accidents at play, --the fracture is usually single (7 cases) multiple (8 cases) and in 13 children out of 15 there was a fracture of the condyle. --the presence of the first dentition and dental germs posed special problems. The treatment is mainly orthopedic, and the fracture is maintained in place by metallic arches which may or may not be completed with a resin dropper. Condyle fractures are treated classically by functional mechanotherapy. The indications of osteosynthesis seem to be limited to cases of very unstable fractures or where these are comminutive. The treatment of sequelae requires techniques very similar to orthodontic apparatuses.

Child↗

[Judicious use of antibiotics in dental practice].

With the discovery of penicillin and entrance into the antibiotic era, the capability of dentists to treat dental infections have changed dramatically. Many antibacterial agents have developed since, but bacterial resistance using diverse mechanisms, have increased concomitantly. Since antimicrobial agents are frequently needed in dentistry, their judicious use is of prime importance. Dental infections can be divided to two main groups according to the origin of the infection. First, odontogenic infections (acute dento-alveolar abscess) originating from the dental pulp are most commonly caused by gram-positive anaerobic or facultative bacteria. Systemic antibiotic should be given concomitantly with drainage of the dento-alveolar abscess, debridment of the root canal of the infected tooth, and placement of inta-canal antimicrobial medication such as calcium hydroxide. Penicillin G, penicillin V (Rafapen) or amoxycillin (moxypen) are the first line systemic antimicrobial agents. In case of no improvement within 2-3 days, second line regimens such as amoxycillin-clavulanate (augmentin), cefuroxime (zinnat) or penicillin and metronidazole are recommended. In patients allergic to penicillin, clindamycinn (dalacin) is preferred over macrolides. The second group of infections originates from the periodontal apparatus, and is caused usually by gram-negative anaerobes bacilli, sometimes with Actinobacillus actinomycetemcomitance (Aa). Systemic antibiotics are only infrequently indicated in this situation, and always accompanied by scaling, root planning and curettage of the infected root and gingiva. In regenerative or post surgical periodontitis, augmentin, metronidazole or metronidazole in combination with penicillin or amoxycillin augmentin are recommended. In aggressive periodontitis the most common pathogen is Aa and therefore tetracycline, augmentin, or metronidazole and amoxicillin are recommended. In necrotizing ulcerative gingivitis, which is caused usually by fusiform bacilli and spirochetes, metronidazole or augmentin are appropriate. In patients with periodontal disease who are allergic to penicillin can be treated with a macrolides.

Aggregatibacter actinomycetemcomitans↗