bluuebunny/crossref_metadata_2025_split huggingface dataset:
The age structure and distribution of Atlantic salmon parr, Salmo salar L., in small tributaries and main stems of the subarctic River Teno, northern Finland
Authors: Erkinaro J. 
Published: July 2006

AbstractParr of the Atlantic salmon in subarctic River Teno, northern Finland (70°N, 28°E), are found to migrate to small tributaries that are not spawning areas for the adult salmon. The age distribution of the salmon differs significantly between these brooks and the natal rivers, the parr in the brooks being typically 2–4 years old, whereas those in the main rivers were mostly of age 0–2 years. The older fish were found in the uppermost regions of the brooks. The ratio of salmon to brown trout decreases towards the upper reaches of the brooks. At least some of the young salmon overwinter in the brooks. However, the number of fish and the area inhabited diminished towards the autumn in some occasions. It is suggested that this migratory behavior may be an adaptational phenomenon that could cause variation in survival among young salmon in the River Teno.
Bone tissue reactions to periodontal dressings.
Authors: Haugen Ellen , Majör Ivar A. 
Published: July 2006

78 rats weighing 180–200 g were used to assess the bone tissue responses to three periodontal dressings (Coe‐pak, Peripac and Ward's Wondrpak). The dressings were implanted subscutaneously on periosteal covered and denuded bone. Sham operated animals served as controls and a comparison btween the responses produced by the three dressngs were made.In one series the dressings remained in situ for 3, 7, 14, 30 and 90 days. Osteocyte damage of varying extent was recorded for all materials. Remodelling of the bone surface adjacent to the dressing was observed. Bone resorption was never foud in the gournd defect produced to denude the bone tissue, but repair of the defect by bone formation was observed after long observation periods. This repair was retarded in some animals were Ward's Wondrpak had been implanted.In another seiries Ward's Waondrpak was implanted against bone for three days, then re‐operated to remove the dressing and the defect allowed to heal for 30 days. The test group exhibited empty bone lacunae and the repair of the defect was retarded or lacking.
Longitudinal therapeutic effects on the periodontal attachment level and pocketdepth in beagle dogs
Authors: Lang N. P. , Morrison E. C. , Löe H. , Ramfjord S. P. 
Published: July 2006

Thirteen healthy Beagles, 3 1/2–5 years of age with moderate to advanced periodontal discase received a thorough scaling and prophylasis followed by four weeks of daily tooth cleaning. After one month, each of the fourposterior quadrants of each dog was subjected to one of the following treatments: 1) subgingival curettage, 2) modified Widman flap surgery with root planing, 3) apically repositioned flap and bone surgery for pocket elimination and 4) scaling and root planing as a control. Toothbrushings was carried out daily. In addition, every 14 days the dogs received a rubber cup and pumice prophylaxis throughout the entire length of the study. At the baseline, 1, 6, 12, 24 and 36 months following treatment, oral hygiene and gingival health were scored and the level of periodontal attachment and pocket depth were measured. The results at one Month suggested an increase in attachment levels which was grater after scaling or subgingival curettage than after flap procedures. Up to 36 months, the established attachment levels were maintained for all treatment groups and no significant difference was found between any of the treatments and the scaled controls. However, in advanced periodontal lesion attachment levels were not maintaned with scaling alone.The present study has shown that the more conservative approaches to the treatment of periodontal disease such as subgingival curettage and Widman flap surgery may be as effective in maintaining clincal attachment levels as elaborate surgical procedures involving osteoectomy.
Histopathogenesis of spontaneous periodontal disease in conventional rats
Authors: Garant P.R. , Cho M.I. 
Published: July 2006

Spontaneously developing gingiitis lesions in the interdental tissue of rats fed a regular pelleted chow and apowdered high sucrose diet were examined in the electron microscope. The subepithelial inlamed connective tissues demonstrated a loss of collagen fibers concomittant with the infiltration of neutrophils, macrophages and lymphocytes. Fibroblasts adjacent to the inflamed gingival epithelium demonstrated cytopathic changes such as dilation of the granular endoplasmic reticulum and diminution of the Golgi complex. Endothelial cells and pericytes were characterized by prominent Gogi apparatuses, numberous mitochondria and well developed granular endoplasmic reticulum. Cytoplasmic processes of both cell types penetrated the vascular basa lamina. Apical migration of the juntional epthelium was preceeded by denudation of the cemental surface by breakdown of the connective tissue attachment.These changes reflect subepithelial tissue breakdwon and a vascular and epithelial micgratory response, probably involving increased synthetic activities.
Preliminary observations on the inhibitory effect of tetracycline on alveolar bone loss in beagle dogs
Authors: Williams R. C. , Sandler M.B. , Aschaffenburg P.H. , Goldharber P. 
Published: July 2006

Alveolar bone loss of selected periodontally diseased teeth in four beagles receiving daily tetracycline per os. was compared to three untreated beagle dogs. The percentage and rate of bone loss was measured radiographically over a 47 month period. This included a preliminary period of 20 months when no animals received antibiotics, and 27 months in which 4 animals were each given 250 mg tetracycline hydrochloride daily. During the preliminary period, all dogs progressively lost alveolar bone. However, with the institution of tetracycline treatment further loss of alveolar bone in the treated animals was arrested or markedly diminished for various intervals of time before resuming the original more accel;erated rate of bone loss. Bone loss in one animal was arrested for 27 moknths, whereas in another dog, the period of arrested bone loss was only 5 monghs. In two animals, bone loss was arrested for 17 months.Bacterial samples from one periodontal pocket in each dog revealed that a Gram negative flora predominated in all animals. Tetracycline administration altered the pocket flora slightly with a shift to more gram positive organisms in the treated animals.The data suggest that daily tetracycline administered orally may be effective in slowing the progressive loss of alveolar bone in beagle dogs.
Effect of sampling on the composition of the human subgingival microbial flora
Authors: Mousquéegs Thierry , Listgarten Max A. , Stoller Norman H. 
Published: July 2006

Eighteen adults with chronic periodontitis participated in an experiment to study the effect of sampling the subgingival microbial flora of periodontal pockets on the subsequent microbial composition of the pocket contents. Samples of bacteria were collected atraumatically with a periodontal curette from periodontal pockets. The sample was suspended in 0.85 N saline containing 1 % gelatin. A drop of the suspension suitably diluted was applied to a microscopic slide and the specimen immediately examined by darkfield microscopy. The microbial flora was classified into coccoid cells, motile cells, spirochetes and “other” microorganisms. The proportion of bacteria in each of these 4 categories was expressed as a percentage, based on the examination of the first 200 bacteria detected in a series of high power fields (mag. × 1200). The microbial composition of the contents of each of 6 pockets was examined at day 0 (baseline data) and each pocket reexamined once either 3, 7, 14, 21, 28 or 42 days later. In addition to the microbial examination, GI and P1I scores and probing depth measurements were also obtained at day 0 and at the reexamination.The results indicated a tendency toward reduced P1I and GI scores at the various reexaminations in comparison to baseline scores. Probing depth measurements did not change significantly. A slight but significant proportional increase in coccoid cells was detectable at 3 days and persisted at more or less the same level for the remainder of the experiment. Spirochetes showed a proportional decrease from baseline during the first week, while motile cells were proportionally reduced only on day 3. No significant changes occurred in the “other” microorganisms. It is not clear from the results if the alterations in the microbial flora were due to the sampling procedure per se or to a change in oral hygiene habits in a population of new patients suddenly more aware of their periodontal status. The clear‐cut changes from baseline to day 3 levels and the subsequent lack of change from the 3‐day through the 42‐day intervals suggest that sampling per se may have contributed only to the changes from baseline noted in the first few days. The change in oral hygiene habits, however, may have contributed not only to the initial changes from baseline, but also to the maintenance of the new microbial proportions at a stable level for the remainder of the experimental period. Despite changes from baseline, all criteria remained well within the range of values that might be expected at periodontally diseased sites in patients with untreated chronic periodontitis.
Effect of scaling and root planing on the composition of the human subgingival microbial flora
Authors: Mousquéegs Thierry , Listgarten Max A. , Phillips Russell W. 
Published: July 2006

The effect of a single session of scaling and root planing on the subgingival periodontal flora of 14 adult human subjects was investigated by darkfield microscopy. At baseline, one randomly selected periodontally diseased site in each subject was assessed for GI and P1I scores, probing depth and the percentage distribution in subgingival debris of coccoid cells, spirochetes, motile cells and other microorganisms. Following a single full mouth scaling and root planing session, these criteria were reevaluated at other initially diseased sites, one per subject and time interval. The intervals tested were days 3, 7, 14, 21, 28, 35, 42, 49, 56, 70 and 90.The P1I and GI scores tended to decrease during the first 14 days, returning to baseline around days 21–28. After another transient decline around 35–42 days the values stabilized around baseline levels till the end of the experiment. Probing depth decreased below baseline during the first 7 days and with the exception of day 28, remained below baseline level till the end of the experiment. Coccoid cells increased from 25.1 % at baseline to 76.1 % on day 3. Return to the baseline level occurred by day 21. Spirochetes did not return to baseline until day 42. The percentage of motile cells decreased significantly from baseline on day 3 only (14.8 % to 3.8 %).The results indicated that a single session of scaling and root planing is capable of disturbing the proportions of certain bacterial forms in the subgingival periodontal flora, and that it may require approximately 42 days for the proportions to return to baseline levels. Probing depth was significantly decreased by the debridement throughout most of the 90‐day experimental period. The proportion of coccoid cells was negatively correlated with both GI and P1I scores, while the percentage of spirochetes was positively correlated with GI and P1I scores as well as probing depth measurements.
A microbiological study of dental calculus
Authors: Sidaway D. A. 
Published: July 2006

Cultures of microorganisms isolated from human calculus have been calcified using a simple in vitro system. All strains had previously produced hydroxyapatite (HAp) under similar experimental conditions.Ultra‐thin sections of specimens embedded in Epon 812 were examined, with a Philips 200 electron microscope, unstained or double‐stained with uranyl acetate and lead citrate.Intracellular crystals of HAp were seen in all strains examined. The majority of Grampositive rods produced only intracellular calcification, usually mesosome associated and extracellular vesicles were rarely seen. In contrast Gram‐negative rods produced extracellular material—vesicles and debris from disrupted cells—which was heavily mineralized. The association of initial intracellular calcification with mesosomes was not always observed.Extracellular calcification was also a feature of some Gram‐positive and all Gram‐negative cocci with cell‐associated deposits apparently originating from the cell wall. A feature of some species, particularly the Gram‐negative cocci, was the presence of randomly arranged spherules of amorphous calcium phosphate within the cytoplasm some of which appeared to be partially converted to HAp. In the majority of microorganisms examined early mineralization was apparently crystalline.It is suggested that extracellular mineralization of Gram‐negative microorganisms may be a significant factor in early matrix calcification in natural calculus.
Functional integrity of gingival crevicular neutrophil polymorphonuclear leucocytes as demonstrated by nitroblue tetrazolium reduction
Authors: Kowolik M. J. , Raebukn J. A. 
Published: July 2006

Gingival crevicular neutrophils were collected from 20 healthy subjects and their ability to reduce nitroblue tetrazolium was investigated by means of a semi‐quantitative histochemical test. 78.04 % (± s.e.m. 0.8 %) of the cells were vital. 42.9 % (± s.e.m. 3.3 %) of the crevice neutrophils were NBT positive as compared to 5.6% (± s.e.m. 0.89%) of unstimulated peripheral venous blood neutrophils from the same patients (p < 0.001). No difference between male and female was found. The results indicate a stimulation of crevicular neutrophils by bacteria. Furthermore, a slight correlation between blood and crevicular neutrophil activity in each individual was found, suggesting that even in the normal state some antigen or other bacterial product in the circulation is capable of stimulating the neutrophils.One patient with hereditary cyclical neutropenia, shown to have a greatly reduced number of crevicular cells, had normal activity of both blood and crevicular neutrophils as measured by this test. These findings, compatible with known immunological results, are compared with the neutrophil function test results in this patient and two other neutropenic subjects.This study supports the view that the gingival crevicular neutrophil is a functional cell capable of contributing towards host defense.
Histological and ultrastructural characteristics of the periodontal syndrome in the rice rat
Authors: Ryder Mark I. 
Published: July 2006

In this study on the periodontal syndrome in the rice rat, observations were made on rice rats fed stock diet and followed from six days to fifteen weeks after birth, and on rice rats fed a high sucrose diet (Diet 700) from weaning (3 weeks after birth) and followed to seventeen weeks after birth.In rats fed stock diet, early massive accumulations of bacterial plaque were seen on erupting posterior teeth with an underlying PMN exudate and a PMN infiltrate within the gingival epithelium and lamina propria. Inflammatory and resorptive changes were rarely seen in the transeptal fiber area and alveolar crest in this group of animals.In rats fed diet 700, similar patterns of bacterial plaque accumulations and PMN infiltrations were seen. At later time periods, this PMN infiltrate was commonly seen to extend through the transseptal fiber area to the alveolar crest where marked osteoclastic activity was noted. Such apical extension of the inflammatory infiltrate was associated with ulceration of the overlying gingival epithelium.
Inflammatory reactions in the gingival region during the development of bacterial plaque in alloxan‐diabetic dogs
Authors: Matsson L. , Attstrom R. , Granath L. 
Published: July 2006

The effect of experimentally induced diabetes on inflammatory reactions in the gingival region of the beagle dog has been studied in connection with the development of dental plaque.The investigation, which was undertaken in 5 dogs, had an intra‐individual design, the increases in the amounts of gingival exudate and crevicular leukocytes during plaque development being studied in each animal before and after the induction of alloxan‐diabetes.The increases in gingival exudate and crevicular leukocytes in response to plaque accumulation showed a tendency to be lower during diabetic compared with non‐diabetic periods. It is suggested that the lower vascular reaction and the reduced leukocyte migration that were observed shortly after onset of the experimental diabetes might reflect an impaired defense mechanism of importance in the longer run for the development of pathological changes in the periodontium.
Histological and ultrastructural characteristics of the periodontal syndrome in the rice rat
Authors: Ryder Mark I. 
Published: July 2006

The periodontal syndrome in the rice rat was studied in animals fed a high sucrose diet. Progressive degenerative and inflammatory changes within the coronal aspects of the rice rat psriodontium (viz. sulcus, epithelium and lamina propria) were noted. PMN's were seen to migrate from blood vessels within the lamina propria, through the basal lamina, and to either the cemental surface or to the bacterial plaque, where a minimal degree of PMN phagocytosis and degranulation was observed. The degree of PMN phagocytosis appeared to be inversely related to the density of bacterial plaque as viewed on the electron microscopic level.Progressive degenerative changes (viz. vacuolization, lipid accumulation, mitochondrial swelling, etc.) were seen in gingivai epithelial cells subjacent to the bacterial plaque, as well as at the basal layer. Similar changes were noted in fibroblasts in the underlying lamina propria. At later stages of observation (8–14 weeks post‐weaning) a prominent population of macrophages and mononuclear cells was seen within the lamina propria. “Clumping” of these cell types with degenerating fibroblasts was a common finding.
Histological and ultrastructural characteristics of the periodontal syndrome in the rice rat
Authors: Ryder Mark I. 
Published: July 2006

In this study on the periodontal syndrome in the rice rat, the progressive inflammatory and degenerative changes were noted in the transseptal fiber area and alveolar crest.The predominant inflammatory cell types within the transseptal fiber area were PMN's, monocytes and macrophages. Progressive degenerative changes were noted in fibroblasts and collagen fibers with replacement of these elements by the inflammatory infiltrate.At the alveolar crest, extensive osteoclastic activity was observed. Expressions of this activity included the presence of prominent osteoclast ruffled borders and osteoclastic phagocytosis of osteocytic cells. Degenerative changes within osteoblasts were noted at later stages.From these observations, the accelerated rate of destruction seen in this animal model can be explained in part by the increase in resorptive elements (macrophages, osteoclasts) with the simultaneous decrease in formative elements (epithelial cells, fibroblasts, osteoblasts).
Quantitation of in vitro cell adhesion to cementum, dentin and enamel
Authors: Brastins E. D. , Labant M. , Fletcher R. D. 
Published: July 2006

The William's blister test for adhesion was used to determine the strength of epithelial and fibroblast cell attachments to cementum, dentin and enamel. Differences of air pressure required (cm H2O) to debond the samples from a cell monolayer were measured and recorded on a strip chart recorder (Fletcher et al. 1977).Gingival and skin‐muscle cells detached at similar pressures from cementum, dentin and enamel. Higher pressures (of debond) were required with cells grown on a polystyrene surface.
Marginal fit and cervical extent of class II amalgam restorations related to periodontal condition
Authors: Arneberg Pål , Silness John , Nordbø Håkon 
Published: July 2006

In 18 dental students, 314 class II amalgam restorations were examined by probe and mirror as well as by radiographs. The examination was repeated subsequent to amendment of defective restorations through finishing procedures. Plaque, gingivitis and pocket depths were recorded at the initial examination and six months after the finishing procedures.Defects were found at the cervical margin of 50 per cent of the fillings at the first examination. Three out of four defects were overhangs, and five out of six overhangs were corrected by finishing. Overhangs, deep pockets and gingivitis were often recorded when the fillings extended beyond the gingival margin. On the other hand, neither the presence nor the elimination of moderately sized amalgam overhangs could be shown to influence the periodontal conditions.
Peripheral blood leucocytes with receptors for extracts of dental plaque
Authors: Hardy G. , Walker D. M. , Guest P. 
Published: July 2006

The proportions of T and B lymphocytes, monocytes and polymorphs have been investigated in blood leucocytes expressing receptors for plaque antigens.In both patients with periodontal disease and in normal subjects, at least 95 per cent of the antigen binding leucocytes were found to be T lymphocytes. Only a mean 2 percent of the leucocytes from diseased and normal groups were B lymphocytes according to their membrane immunoglobulin. Antigen binding monocytes or polymorphs detected by phagocytosis were uncommon (a mean of 0 and 2 per cent for patients and normal subjects respectively). No differences were found between the proportions of T and B lymphocytes or phagocytic cells constituting the antigen binding leucocytes in patients or controls.There is no evidence of clonal deletion or receptor blockade of a particular subpopulalion of leucocytes amongst the antigen binding cells in severe periodontal disease.
The influence of advanced periodontitis on the psychophysical threshold level of periodontal mechanoreceptors in man
Authors: van Sleenherghe D. , VAN DEN Bergh A. , DE Vries J. H. , Schoo W. H. 
Published: July 2006

Two groups of volunteers were examined with regard to the threshold level of a maxillary incisor for axialIy applied forces. One group showed an advanced periodontilis around the examined tooth, while the other group presented no clinical periodontal pathology. The ascending method of limits was used to determine the psychophysical threshold level.The relationship between the threshold level and the force application rate appeared to be linear on a lin‐log and a log‐log display. Higher rates gave lower threshold levels. For equal rales, the threshold level of the periodontilis group was significantly higher than for the control group.The results indicate that the periodontal mechanoreceptors are sensitive to the rate of force application, whatever the periodontal condition. Advanced periodontitis. however, clearly impairs the tactile function of the tooth supporting tissues.