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Treatment of endodontic perforations by guided tissue regeneration.

Case reports of mandibular molars with iatrogenic perforations are presented. Such perforations have been treated with internal amalgam repair or by surgical intervention. However, the potential exists for tissue migration and pocket formation. The use of guided tissue regeneration as a barrier for apical migration is beneficial in surgical treatment of perforations. Follow-up examination of perforated teeth treated with resorbable barriers showed successful repair. Results obtained with this technique offer the possibility of a successful repair for an otherwise hopeless complication of endodontic therapy.

Absorbable Implants↗

Tissue healing in implants immediately placed into postextraction sockets: a pilot study in a mini-pig model.

OBJECTIVE: A pilot in vivo study was conducted to evaluate (1) the rate of osseointegration at apical, middle, and coronal levels of oral implants immediately installed into fresh extraction sockets; (2) the maturation of the newly formed bone surrounding implants during 60 days of healing; and (3) the epithelium seal development. STUDY DESIGN: The premolars of 8 male adult mini-pigs were extracted at each mandibular site under general anesthesia. In the experimental side, Frialit-2 implants were immediately inserted. The gap between bone and implants ranged between 3 and 6 mm circumferencially. Bone specimens were obtained at 7, 15, 30, and 60 days after surgery for histologic and histomorphometric studies. Bone-to-implant contact (BIC), bone volume, trabecular thickness, number, and separation were recorded. Nonparametric exact tests were used to evaluate data. RESULTS: BIC at the coronal level was observed close to 0% at day 7 and increased up to 60% at day 60 after surgery on an average. BIC increased from 11.7% to 47.38% at middle level and from 53.4% to 67.38% at apical level from day 7 to day 60. With respect to bone maturation, in the earlier stages of healing, many thin trabeculae were observed, which, particularly at coronal level, became significantly fewer and thicker in more advanced stages. At day 60, the features of the bone were similar to those of baseline. The epithelium never migrated more than 1.8 mm apically to the top of the alveolar bone level. CONCLUSION: When implants are placed immediately into fresh extraction sockets, in minipig models osseointegration also occurs without initial bone contact.

Analysis of Variance↗

A human salivary protein which promotes adhesion of Streptococcus mutans serotype c strains to hydroxyapatite.

The aim of this study was to investigate the nature of one of the factors in human submandibular-sublingual (SMSL) saliva which promotes the adhesion of Streptococcus mutans serotype c strains to hydroxyapatite (HA) surfaces. Gel filtration chromatography of SMSL saliva on Trisacryl GF2000 gave a void volume peak which contained the major fraction of adhesion-promoting activity for S. mutans JBP to HA. Maximum adhesion-promoting activity, however, eluted slightly later than the maximum 220-nm absorbance of the void volume peak. Gel filtration of the void volume material after treatment with sodium dodecyl sulfate (SDS) gave an early-eluting larger peak followed by a smaller peak with which the adhesion-promoting activity was associated. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed the presence of relatively slowly migrating material associated with the larger inactive peak, presumably mucin, and a faster-migrating band(s) associated with the smaller active peak. SDS-PAGE indicated molecular weights in the range of 300,000 to 350,000 by extrapolation from size standards. Comparison of SMSL from five individuals showed the presence of single bands or double bands associated with adhesion-promoting activity, indicating genetic polymorphism. The active material did not resemble either secretory immunoglobulin A, based on SDS-PAGE and immunoassay, or fibronectin, based on SDS-PAGE, and also differed in molecular weight from salivary mucins and salivary constituents previously reported to promote aggregation of certain oral bacteria, but a relationship to these materials cannot be excluded. This adhesion-promoting material may play a significant role in the initial colonization of tooth surfaces by S. mutans strains.

Bacterial Adhesion↗

The effect of EDTA on the attachment and growth of cultured human gingival fibroblasts in periodontitis-affected root surface.

The purpose of the present study was to analyze the effects of 5% and 24% EDTA on the attachment of gingival fibroblasts to periodontally diseased root surfaces. A flat root surface was created on human teeth that were extracted due to severe periodontitis. The teeth were etched with the following concentrations of etylediaminetetraacetic acid (EDTA) for two minutes: 5% (group I) and 24% (group II). Group III was soaked in saline and served as a control. The specimens and fibroblasts were incubated in a culture medium for 24 hours each day for one and two weeks and photographed using scanning electron microscopy. Each specimen was examined for the migration of cells into the etched and non-etched root surface. No fibroblasts could be detected on the saline groups. More fibroblasts could attach to the surface treated with 24% EDTA than with 5% EDTA. It was concluded that supersaturated EDTA at 24% enhances the attachment of gingival fibroblasts to the root surface.

Acid Etching, Dental↗

Coronal displacement of cementum: correlation between age and coronal movement of cementum in impacted teeth.

This study was conducted on 48 impacted and 51 erupted maxillary permanent canine teeth extracted from healthy patients aged 13-73 years. Longitudinal buccolingual ground sections were prepared. The distance between the edges of cementum and enamel in each specimen was measured with an eyepiece micrometer. A correlation test was applied between age and the distance between enamel and cementum measurements. In impacted teeth, depending on age, cementum had a tendency to overlap the enamel; there was a linear correlation between age and coronal displacement of cementum (n-2 = 46, r = 0.69, distance (microgram) = 21.7* age (years) -440, p < 0.001). No correlation between age and coronal displacement was found in erupted teeth (n-2 = 49, r = -0.23, p > 0.05). Results of the study indicated that the cementum in impacted teeth migrated coronally during the ageing process. This may be related to continually erupting forces which affect the impacted teeth and may be a mechanism by which the teeth are protected at the cemento-enamel junction (CEJ). This phenomenon could be used in forensic dentistry to determine age. The absence of correlation in erupted teeth could be attributed to the masking effects of extrinsic factors.

Adolescent↗

Cytotoxic and genotoxic effects of resin monomers in human salivary gland tissue and lymphocytes as assessed by the single cell microgel electrophoresis (Comet) assay.

Malignant tumors of the three major pairs and the numerous minor salivary glands in humans are rare, and little is known about their various etiologies. Considering the fact that resin monomers from dental restorative materials are released into the saliva and diffuse into the tooth pulp or gingiva, mucosa, and salivary glands, this may potentially contribute to tumorigenesis. Resin monomers may also be reabsorbed and reach the circulating blood as well. Whereas the cytotoxic potential of some components has been clearly documented, data on genotoxicity in human target cells require further investigation. In the present study, genotoxic and cytotoxic effects of three common methacrylates are investigated in human samples of salivary glands and peripheral lymphocytes. The Comet assay was used to quantify DNA single strand breaks, alkali labile and incomplete excision repair sites in salivary gland probes and lymphocytes of 10 volunteers. The xenobiotics investigated were triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and 2-hydroxyethylmethacrylate (HEMA), with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and dimethyl sulfoxide (DMSO) as controls. DNA migration was analyzed using the tail moment according to Olive (OTM). Cytotoxicity was monitored using trypan blue staining. With TEGDMA concentrations at 10(-5)m (10(-3)m), UDMA at 10(-7)m (10(-7)m), and HEMA at 10(-3)m (10(-5)m) significant enhancements of DNA migration were achieved in tissue cells (lymphocytes) as compared to the negative controls. At higher concentrations of up to 2.5x10(-2)m, induced DNA migration was expressed by OTM at 10.7 for TEGDMA in tissue cells (8.7 in lymphocytes), 10.5 for UDMA (6.4), and 9.7 for HEMA (6.1). The viability of the cell systems was not affected as concerns the threshold level for the assay of 75% viable cells except for the highest concentration tested for TEGDMA and UDMA in tissue cells. At higher concentration levels, all tested substances induced significant enhancement of DNA migration in the Comet assay as a possible sign for genotoxic effects in human salivary glands and lymphocytes. These data add to the results of prior studies in human peripheral lymphocytes and give evidence of a possible risk factor for tumor initiation in human salivary glands.

Aged↗

Cell and fiber attachment to demineralized dentin from periodontitis-affected root surfaces.

This study assessed connective tissue and epithelial responses to dentin specimens obtained from periodontitis-affected roots of human teeth after surface demineralization. Rectangular dentin specimens with opposite faces of root and pulpal dentin were prepared from beneath root surfaces covered by sheets of calculus. One half of the specimens were treated with citric acid, pH 1, for 3 minutes, while the remainder served as untreated controls. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. Four specimens in each group were available 1, 3, 5 and 10 days after implantation. Histologic and histometric analyses included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. Analyses within each group comparing root and pulpal surfaces showed no differences between any of the parameters. Comparisons between experimental and control groups showed that demineralized surfaces had a greater number of cells attached, fiber attachment occurred and epithelial downgrowth was inhibited. Surface demineralization of dentin from periodontitis-affected roots predisposed toward a connective tissue attachment.

Animals↗

[The dilemma of the 2d primary molar].

Extensive carious lesions in primary molars often confront the dentist with a dilemma: extraction or restoration. The primary molar constitutes an important element in the development of the dentition. If extraction is considered, the dentist should be aware of the possible risks towards malocclusion or malposition. In order to understand these consequences a brief summary of normal dentition development is given, followed by a description of factors influencing development of dentition after premature extraction of a second primary molar. Premature extraction causes a disturbance in the eruption of the successor and migration of the neighbouring teeth. The eruption of the bicuspid can be delayed or accelerated according to the stage of root formation. The rate, amount and direction of migration depends on the extracted element, time of loss, spacing or crowding, eruption sequence, dental relationship, intercuspation, interaction of soft tissues and dental arch, supra-occlusion and the leeway space. To conclude the treatment modalities of pulp pathologies in primary molars are outlined. In children with deep carious lesions a treatment plan involves the child's medical history and social development as well as orthodontic, preventive and restorative aspects.

Child↗

Localized bacillary angiomatosis in the oral cavity: observations about a neoplasm with atypical behavior. Description of a case and review of the literature.

Bacillary angiomatosis is a rather frequent infectious pathology appearing mainly in the skin but can also affect the liver, spleen, heart, bones, lungs, muscles, central nervous system and other organs. The localization of the lesion in the oral cavity is rather rare, as it is evident in the literature. Bacillary angiomatosis can be clinically similar to the Kaposi's sarcoma and histologically confused with angiosarcoma, epitheloid hemangioma and pyogenic granuloma. A case of bacillary angiomatosis of the oral cavity in an immuno-competent patient is described. The high tendency to relapse, the capability in migration and to involve several localizations at the same time have induced the authors to deepen the research to exclude the possibility that it could be a Kaposi's sarcoma or a pyogenic granuloma and to get to an accurate diagnosis in order to resolve the disease.

Adolescent↗

Identification, partial characterization, and distribution of versican and link protein in bovine dental pulp.

The dynamics of changes in the cellularity and extracellular matrix composition of dental pulp varies considerably during tooth development and maturation. In this paper, we studied matrix proteoglycans where we hypothesized that they played important roles in structural, spatial, and transport aspects of pulpal development and maintenance. The pulpal tissue was collected from partially erupted bovine incisors, pulverized, and then extracted with 6 M guanidine-HCl. The extract was subjected to anion column chromatography (DEAE-8HR), and the fractions collected were screened by dot-blot immunoassay by means of monoclonal antibodies generated against 4- and 6-sulfated chondroitin sulfate isomers, and keratan sulfate, 2-B-6, 3-B-3, and 5-D-4, respectively. The chondroitin-6-sulfate was the major glycosaminoglycan species and occurred as a large-molecular-weight proteoglycan (> 500 kDa). After further purification, it was subjected to agarose/acrylamide composite gel electrophoresis, and it migrated as a single band stained with Stains-All. The band was immunopositive against antibody 3-B-3 by Western blot analysis. The partial amino acid sequence analyses of the core protein clearly indicated this molecule to be versican. The presence of link protein was also confirmed by Western blot analysis with an anti-link protein monoclonal antibody, 8-A-4. Furthermore, immunohistochemical study indicated that the distributions of versican and link protein coincide in the dental pulp and are enriched in the peripheral area of the tissue just beneath the odontoblast layer. Since the dental pulp contains hyaluronan, versican may bind to hyaluronan via its hyaluronan-binding domain, where this association is stabilized by link protein. This complex, then, could form large hydrated proteoglycan aggregates that fill the extracellular space, support odontoblasts, and/or facilitate the transport function of metabolites and nutrients within the tissue.

Amino Acid Sequence↗

A neutrophil disorder induced by capnocytophaga, a dental micro-organism.

We recovered capnocytophaga, a gram-negative anaerobe implicated in the pathogenesis of periodontal disease, from two patients with a history of dental infections. Neutrophils from both patients failed to acquire the asymmetric shape characteristic of normal neutrophils. Fluorescein staining of the patients' living neutrophils remained diffuse and patchy instead of showing the normal pattern in which the fluorescence is swept into the rear of the cell. The locomotion of one patient's neutrophils in vitro was less than 50 per cent of that of normal neutrophils, and migration of this patient's neutrophils into dermal abrasions was reduced, although phagocytosis and nitroblue tetrazolium reduction were normal. All abnormalities of neutrophil morphology and function disappeared after eradication of the capnocytophaga infections. Sonicates and culture medium of capnocytophaga contained a dialyzable substance that caused normal neutrophils to behave like neutrophils obtained from the infected patients.

Adolescent↗

Contraction and organization of collagen gels by cells cultured from periodontal ligament, gingiva and bone suggest functional differences between cell types.

Monkey periodontal ligament fibroblasts (MPLF cells), human gingival fibroblasts (HGF cells), rat embryonic calvaria cells (REC cells), porcine periodontal ligament epithelial cells (PPLE cells) and rat osteosarcoma 17/2 cells (ROS cells) were incorporated into 3-dimensional collagen gels plated in 60 mm Petri dishes in order: first, to measure the capacity of these cell types to contract; second, to investigate cell-collagen and intercellular relationships during contraction; and third, to define the cellular contribution to tissue contraction in an in vitro system. Measurements at times up to 72 h on 3 ml gels containing 5 x 10(5) cells and with a collagen concentration of 1.20 mg/ml showed that MPLF cells contracted the gels at a significantly greater rate (P less than 0.001) than did the other cell types. In addition, contraction started sooner and was of greater extent than with the other cells. HGF cells contracted the gels more rapidly than REC and PPLE cells, while ROS cells caused no contraction. Several stages of gel compaction could be defined: (1) the attachment of cells to collagen; (2) cellular spreading within the collagen fibre matrix; (3) organization and alignment of collagen fibres by cell processes; (4) cell migration; (5) establishment of intercellular contacts; and (6) the development of a cellular reticular arrangement within the gel and the extension of this arrangement into a 3-dimensional, tissue-like, honeycomb network. Electron microscopic observations on 0.1 ml gels containing MPLF cells showed that, in the early contractile phase, numerous cell processes attached to or enclosed collagen fibrils. These processes contained microfilamentous material and few organelles. In compacted gels, the cells contained an increased amount of distended rough endoplasmic reticulum and Golgi membranes. Since MPLF cells have the capacity for vigorous contraction of the collagen gels and since they develop a reticular, 3-dimensional structure in compacted gels that is reminiscent of the relationship of periodontal ligament fibroblasts to collagen fibres in vivo, it is suggested that they could provide the major force necessary for tooth eruption in vivo. This system also provides a well-defined in vitro model to study the sequential stages that occur during contraction processes.

Animals↗

Specific cementum attachment protein enhances selectively the attachment and migration of periodontal cells to root surfaces.

A specific cementum attachment protein (CAP) was identified in human cementum and found to bind with high affinity to non-demineralized root surfaces, hydroxyapatite and fibronectin. Attempting to elucidate the biological function of this protein and its possible role in cementogenesis the capacity of CAP to promote selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro was assessed. Human gingival fibroblasts (HGF), periodontal ligament cells (HPC), and alveolar bone cells (HABC) were labeled with [3H]Thymidine during their exponential growth phase. Root slices, 300 microns thick, were incubated with increasing concentrations of CAP. Untreated and fibronectin (FN) treated root slices served as negative and positive controls, respectively. Migration was assessed by placing root slices on confluent layers of labeled cells maintained in serum free medium and determining the number of cells migrated onto the root surface 3 days thereafter. Attachment was assessed by incubating root slices with labeled cell suspensions for 2 h and determining the number of attached cells. CAP promoted both cell migration and attachment dose dependently. HABC responded better than HPC and HGF to CAP treated root slices, and HPC response was higher than that of HGF. Cell attachment was dose dependently inhibited by synthetic RGD peptides. FN did not affect the migration of HGF, barely enhanced that of HABC, and was less potent than CAP at enhancing the migration of HPC. FN was more effective than CAP in promoting the attachment of HGF to root slices, but it was as potent as CAP in supporting the attachment of HPC and HABC.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗

[Health status of asylum seeking children].

INTRODUCTION: The aim of this investigation was to describe asylum seeking children's social and family situation, health status, strain factors connected with migration, and to unveil practice relevant indicators, which can furthermore delimit children with special needs. MATERIAL AND METHODS: A cross section investigation of asylum seeking children, who in the first half of 1997 were accommodated in The Danish Red Cross Reception Centre and examined by a doctor and/or a public health nurse according to the rules laid down by The Danish Red Cross Social and Health Department. If language problems occurred, an interpreter was present at the examination. Data were collected from the medical record of the child and the parents. RESULTS: The investigation included 364 children. 59% of the children had 306 diagnoses or symptoms, 17% of the diagnoses or symptoms were referred to a specialist or a psychologist. The children came from 25 different countries. 43% came with both parents. The most frequent symptoms in the children were tooth and skin problems and enuresis. DISCUSSION: On the background of disease prevalence, asylum seeking children do not seem to be more frequently ill than children living in Denmark. It is considered that the present investigation could successfully be repeated with a view to universal validity. In the medical records, asylum seeking children's physical health situation is well described, whereas symptoms arising from the flight and experiences are sparsely described. It is recommended that an investigation is carried out, in which both the children's physical and mental health situation is described.

Adolescent↗

Root exposure in the primary dentition studied in human skulls.

The aims of the present study were to examine, on the primary dentition of 75 human dried skulls, the distance from the cemento-enamel junction (CEJ) to the alveolar bone crest, and to evaluate its relation to developmental age, bone morphology and attrition. The measurements from the CEJ to the alveolar crest were longer for the maxillary teeth, the second molars showed the shortest measurements, while the cuspids showed the longest. Significant positive partial correlations were found between age and the distance from the CEJ to the alveolar crest when controlling for attrition (r = 0.64), and between age and attrition when controlling for the distance from the CEJ to the alveolar bone crest (r = 0.54). The partial correlation between migration and attrition when controlling for age proved to be not significant (r = 0.13). Significant correlations were found between age and the distances from the mental foramen to: the alveolar crest (r = 0.90), and to the lower border of the mandible (r = 0.97). These findings suggest that root exposure takes place in the primary dentition, as the result of continuous eruption at a faster rate than formation of alveolar bone, presumably to compensate for facial growth.

Age Factors↗

Significance of early healing events on periodontal repair: a review.

Wound healing in an incisional wound is a highly predictable process which has been studied extensively hour-by-hour and day-by-day. Healing in a periodontal defect following gingival flap surgery is, conceptually, a more complex process as one wound margin consists of calcified tissue, including the avascular and rigid root surface. Another complicating factor in this wound healing is the transgingival position of the tooth. Experimental studies, however, have indicated that healing at a dento-gingival interface under optimal conditions occurs at the same rate as in a skin wound. Generally, periodontal healing is characterized by maturation of gingival connective tissue, limited regeneration of alveolar bone and cementum, and the formation of a long junctional epithelium. Such observations have nurtured the hypothesis that the epithelium of the surgical flap needs to be prevented from early access to the root surface during the healing period to achieve connective tissue repair of the root surface-gingival flap interface. Recent experimental findings suggest, however, that connective tissue repair to the root surface following reconstructive periodontal surgery is a function of the establishment and maintenance of a root surface-adhering fibrin clot. Since fibrin adherence to the wound margins is a natural event, it is additionally suggested that apical migration of the gingival epithelium in periodontal surgical wounds may only follow interruption of the adherence of the fibrin clot to the root surface.

Animals↗

Accidental swallowing of a gold cast crown during orthodontic tooth separation.

Accidental swallowing of a gold cast crown that became loose after separation with brass wire for orthodontic band placement, is reported. The intervention to remove the ingested crown subsequent to its location in the GI tract on immediate radiographic examination of chest and abdomen included endoscopic examination. Since the crown had past distal to the duodenum it was decided to keep a watch on its movement by daily radiographic examination. The crown passed with excreta on the 5th day uneventfully. Literature on ingestion of foreign bodies of dental origin is reviewed. Possible emergencies and their management is discussed.

Adolescent↗

Autoradiographic analysis of odontoblast replacement following pulp exposure in primate teeth.

Cell migration and replication associated with odontoblast replacement occurring soon after pulp exposure in primate teeth were studied. Class 5 cavity preparations resulting in pulp exposures were restored with a calcium hydroxide-containing capping agent and amalgam. Eighty-four and 96 h after this the animals were injected with 0.5 microCi/g body wt tritiated thymidine (sp. act. 6.7 Ci/mM). Teeth were extracted 6, 8, 10 and 12 days after treatment. The number of labelled cells as well as the number of grains per labelled cell were counted for odontoblast-like, fibroblast-like and perivascular cells in three 60 x 260 microns zones. These zones represented the odontoblast and cell-free (zone 1), cell-rich (zone 2) and deep pulp (zone 3) areas of normal pulp tissue. Ten sections centred around the mid-point of the exposure were counted for each tooth. Matrix formation and labelled odontoblast-like cells were observed at the interface between the capping agent and the pulp as early as day 8. Other significant findings were: (1) an increase in labelled odontoblast-like cells in zone 1 over time, suggesting a continual influx of differentiating cells; (2) an increase in labelled cells in zone 1 over time with a concurrent decrease in zone 3, suggesting that the influx of cells in zone 1 was from the deeper pulp; and (3) differences in grain counts between zones, treatment times and cell types, indicating that at least two DNA replications had occurred between initial treatment and final odontoblast-like cell differentiation.

Animals↗