bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histopathology of artificial periodontal defects in beagle dogs before and after ligature removal
Authors: Jansen Jan 
Published: July 2006

The aim of the resent study was to investigate the histopathological characteristics of artificial periodontal defects before and after removal of ligatures. The defects were created in 12 young adult beagle dogs using cotton floss ligatures. The supracrestal dentogingival fibres were dissected around 6 lower premolars (2P2, 3P3, and 4P4) after which closely adapted copper bands were cemented to the teeth. After 3 weeks these copper bands were replaced by subgingival cotton floss ligatures which were left in place for a further 11 weeks. The placement of ligatures around the different teeth and their removal prior to sacrifice was scheduled to provide histological observations of the periodontal defects both with ligatures in situ, and 1 day and 1, 3, 7, 15, or 31 weeks after their removal.Defects with ligatures in situ showed histopathological characteristics of advanced chronic periodontitis. Removal of the ligatures and the subsequent production of a notch (to mark the bottom of the pocket) resulted initially in an exacerbation of the inflammatory process but 3 weeks after ligature removal, a distinct decrease in size of the infiltrated connective tissue (I. C. T.) could be observed especially in the deeper part of the lesion. The tissues of the periodontium showed signs of repair whack became more pronounced with time. There was no indication that the lesion had become progressive in the remaining period of 7–31 weeks after ligature removal.It is concluded that the maintenance of the established lesion is dependent on the persistence of subgingival plaque containing ligatures.
Loss of connective tissue attachment in the marginal periodontium of the mouse following blockage of eruption
Authors: Beertsen Wouter , Everts Vincent , Hoeben Kees 
Published: July 2006

Following blockage of eruption of continuously erupting teeth in rodents, regressive changes occur in the marginal periodontium resulting in detachment of periodontal ligament from the root surface and concomitant apical migration of the functional epithelium. In the present investigation we attempted to identify the mechanisms that are possibly responsible for these changes which occur in the absence of dental plaque.Mice were killed at time intervals varying from one hour up to nine months following pinning their lower right incisor to the surrounding alveolar bone. Stereologic analysis of ultrathin sections revealed that, on the pinned side, the collagen content of the periodontal ligament adjacent to the apical termination of the functional epithelium was substantially less as compared with the ligament at more apical levels. The low volume density of collagen close to the functional epithelium was accompanied by a relatively high amount of phagocytosed collagen in fibroblasts. The volume density of collagen‐containing vacuoles in these cells correlated well with the rate at which the periodontal ligament was detached from the tooth, thereby suggesting that collagen degradation in this area is likely to be performed by connective tissue cells. In addition, it was observed that layers of afibrillar cementum were deposited against the root surface. This would seam to suggest a local disturbance in the incorporation of periodontal ligament fibers in the cementum and could possibly facilitate therapid apical progression of the junctional epithelium during the course of the experiment.
An attempt to simulate junctional epithelium of human gingiva in vitro
Authors: Salonen J. , Santti R. 
Published: July 2006

Pieces of human masticator mucosa were maintained in a Trowell‐type organ culture. The explants were placed on their side on either microporous filters or decalcified dentin matrix slices. The presence of serum in the culture medium enhanced epithelial outgrowth (epibolus) from the explants. The epibolus grew longer in contact with the substratum than along the free connective tissue surface of the explant.When grown on microporous filters, the flow of migrating cells was directed between the explant and substratum. As a sign of epithelial attachment to the filter, a structure morphologically similar to basal lamina and hemidesmosomes was seen. The decalcified dentin matrix, however, caused the epithelial cells to migrate outwards from the explant. The explants became loosely attached to the matrix. Although some electron‐dense material was secreted into the contact area, a typical basal lamina was not seen.
New sustained release dosage form of chlorhexidine for dental use
Authors: Soskolne Aubrey , Golomb Gershow , Friedman Michael , Sela Michael N. 
Published: July 2006

This study was carried out to examine the release kinetics of chlorhexidine from a sustained release device (S. R. D.) prepared from ethyl cellulose (fast S. R. D.) or ethyl cellulose with polyethylene glycol (slow S. R. D.) and to examine the effects on the bacterial flora of pockets in patients with periodontal disease.It was shown that fast S. R. D.'s release up to 80% of the chlorhexidine within the first 3 days in insertion in periodontal pockets, whereas the slow S. R. D.'s release 50% of the chlorhexidine content after 6 days. The release kinetics of chlorhexidine from S. R. D.'s placed in pockets as expressed by the Higuchi system (Higuchi 1963) indicate that it is diffusion controlled. The rate of chlorhexidine release is dependent on the structure of S. R. D., the drag concentration within the device, and the effective surface area.The microbial flora of sixteen pockets from 6 patients were examined using darkfield microscopy at day 0, 3, 10, and 14 after treatment with S. R. D.'s containing, chlorhexidine or placebo S. R. D.'s. The pocket depths ranged from 5–8 mm. The chlorhexidine‐treated group showed a marked decrease in the relative proportions of motile rods and spirochetes and a corresponding increase in non‐motile organisms compared to the flora prior to chlorhexidine treatment or compared to the flora of the placebo treated pockets. These differences were significant up to 10 days post treatment (P < 0.0025).The study indicated the effectiveness of ethyl cellulose polymers as S. R. D.'s in vivo and their ability to reduce the relative proportions of the motile organisms of periodontal pockets to negligible amounts.
ELISA and conventional techniques for identification of black‐pigmented Bacteroides isolated from Periodontal pockets
Authors: Dzink J. L. , Socransky S. S. , Ebersole J. L. , Frey D. E. 
Published: July 2006

Conventional biochemical characterization and an ELISA technique were compared for their ability to identify reference cultures and fresh isolates from suppurating and non‐suppurating periodontal pockets, as well as healthy gingival sulci in the same individual. Antisera to Bacteroides gingivalis strain 381, Bacteroides intermedius strains 581 and VP1 8944, and Bacteroides melaninogenicus ss. melaninogenicus strain 287 were prepared by immunizing rabbits. The antisera were conjugated with peroxidase and appropriate dilutions were chosen to minimize cross‐reactions in the ELISA technique. Conventional characterization of the isolates included cellular and colonial morphology, biochemical characterization, and gas liquid chromatography of acid end products. The antisera appeared to be specific for each black‐pigmented species, since cross‐reactions were not observed to reference strains of heterologous species. There was a 94% agreement between the ELISA and conventional identifications of over 300 fresh isolates from periodontal sites.The predominant black‐pigmented Bacteroides species isolated from suppurating sites was Bacteroides intermedius using either identification technique. The median value of proportions of this species was significantly increased in the suppurating periodontal pockets (16.5%) when compared to non‐suppurating deep periodontal pockets (3%) and healthy gingival sulci (0%). Significant differences in proportions were not observed for the other species of black‐pigmented Bacteroides.
Furcation development of human mandibular first molar teeth
Authors: Bower Robert C. 
Published: July 2006

A study was performed to clarify the temporal sequence of bifurcation development in human mandibular first molar teeth and to investigate the development of features of bifurcation morphology previously described in extracted teeth. This report presents the histometric findings from graphically reconstructed teeth at varying stages of development.Sixteen developing teeth were graphically reconstructed from tracings of serial sections of thirteen grossly and histologically normal human foetuses ranging in post fertilization age from 17 to 38 weeks. Accuracy of reconstruction was tested by retracing and repeated reconstruction and found to be acceptable.Furcation development began at about 24 weeks post fertilization with the appearance of two epithelial nodes which approximately maintained their position relative to one another at a time when the rest of the developing tooth expanded. These nodes were joined to the epithelial cap by isthmuses of epithelial cells. As furcation development occurs prior to root formation, it should be considered part of crown development. In the area of the developing furcation entrance the buccal isthmus of epithelial cells was narrower mesio‐distally than the lingual isthmus. The epithelial nodes and associated isthmuses were located within the ectomesenchymal tissue of the base of the dental papilla.These findings suggest the embryologic origins of enamel projections into the furcation, the difference in diameter between the buccal and lingual furcation entrances, and the abundance of cementum in the furcation area.An incomplete epithelial diaphragm, such as has been described in the marmoset, was not observed in any of the specimens examined.
A longitudinal study of crevicular fluid in periodontal disease in beagles
Authors: Mukherjee Sabyasachi , Das Arup K. , Patel Minu K. 
Published: July 2006

A longitudinal study on the composition of crevicular fluid (CF) and serum was carried out in seven beagle dogs during a period from health to 16 weeks of gingivitis and then 8–10 weeks of ligature induced periodontitis (LIPD). The fluids were collected at weekly intervals and the pH and the concentrations of Ca, Mg, Na, and K and the protein profile were determined. Also at weekly intervals, the plaque index, gingival index, calculus index, and pocket depth and attachment loss were recorded for the teeth from which crevicular fluid was collected. Radiographs were taken on the 0 day and after the dogs were sacrificed. Histopathological studies were carried out following sacrifice of the dogs, and the distances between the cemento‐enamel junction and the coronal end of the junctional epithelium and the cemento‐enamel junction and the crest of the alveolar bone were measured.A two‐way ANOVA analysis of the two fluids (CF and serum) and of the two diseases (gingivitis and periodontitis) showed significant differences between the two fluids and between the two diseases. Further statistical analysis showed that in serum none of the constituents studied differed significantly between gingivitis and LIPD, but a significant rise in the concentrations of Ca, Mg, and K was observed in CF during LIPD. The pH of CF was significantly lower during LIPD, but no significant change was observed in the concentration of Na ion. An apparent relationship was observed only between the concentration of K ion in CF and the attachment loss during LIPD.The serum protein profile remained unchanged throughout the period of this study. During gingivitis the CF protein profile was identical to that of serum, but during LIPD a new protein peak appeared. This material had a molecular weight of < 200,000 daltons. Histopathological and radiographic analysis showed bone loss in all but one dog during LIPD. Histopathological study also showed no significant difference in the distance between CEJ and the coronal end of the junctional epithelium between the ligated and the non‐ligated sides. This study showed that in beagle dogs the CF differed significantly from that of serum. Also, LIPD caused significant changes in both ionic concentrations and protein profile of crevicular fluid.
Inhibition of plaque growth by zinc salts
Authors: Harrap G. J. , Saxton C. A. , Best J. S. 
Published: July 2006

Certain metal salts inhibit the growth of dental plaque. The effect of zinc salts was investigated because of contradictory reports in the literature. Using cultures of human plaque, artificial dental plaques were grown in vitro on aluminium strips. The effect of various zinc salts was examined by treating the strips intermittently with solutions of the salts during the period of growth. The action of mouthwashes containing zinc salts in vivo on plaque growth was determined in human volunteers.All the water‐soluble zinc salts that were tested gave a similar concentration‐dependent inhibition of plaque growth in vitro. The effectiveness of the treatment was reduced by increasing the time allowed for growth after the final application of zinc.Solutions of zinc (17–19 mM) as the citrate or phenolsulphonate salt, gave about 30% reduction in the extension of plaque along the gingival margin in vivo over 16 hours. Subjects with high rates of plaque growth with the placebo mouthwash were most affected by zinc salts. Increasing the zinc concentration to 30 mM did not further increase the activity. Previous reports of low activity of zinc against plaque growth in vivo are explained by too low a concentration of zinc or too low a frequency of application. The results confirm that zinc salts, including zinc citrate, inhibit the growth of plaque in vivo and in vitro.
An experimental study of new attachment procedure in beagle dogs
Authors: Aukhil I. , Simpson D. M. , Schaberg T. V. 
Published: July 2006

The present pilot study was designed to examine the healing sequence when cells from the PDL are allowed to migrate coronally and populate the curetted root surface.Mucoperiosteal flaps were reflected around the premolars and mandibular incisors of two beagle dogs with naturally‐occurring periodontal disease. The roots were thoroughly planed, and grooves were marked at the level of the crest of remaining alveolar bone. Millipore filters (pore size 3 microns) were adapted circumferentially to the roots and sealed to the teeth above the CEJ with cyanoacrylate before suturing the flaps. Histologic analysis of the experimental and sham‐operated control teeth was done at 5, 7, 8, 10, and 12 weeks after the surgery.An initial phase of root resorption was followed by new connective tissue attachment coronal to the groove in successful experimental teeth. No new connective tissue attachment could be seen in the controls although the JE appeared to be located slightly coronal to the groove with time.The findings of the present study suggest that the chances of obtaining a new connective tissue attachment may be enhanced if surgical procedures are designed to allow selective population of curetted root surfaces by cells arising from the PDL.
The ultrastructure of the gingival epithelium in smokers'melanosis
Authors: Anders Hedin and C. , Larsson ÅKe 
Published: July 2006

The ultrastructural morphology of melanocytes and keratinocytes was studied in clinically pigmented and non‐pigmented gingival tissue from smokers and non‐smokers. No differences were found between clinically pigmented lesions in smokers and non‐smokers. In contrast, clinically non‐pigmented tissue of smokers contained significantly more melanin‐loaded keratinocytes as compared to that of non‐pigmented non‐smokers. In tissue of smokers and pigmented non‐smokers melanocytes contained well melanized melanosomes (stages III and IV) as compared to non‐pigmented tissue of non‐smokers where stage II melanosomes dominated.It was concluded that tobacco smoking may be a causative factor in melanin pigmentation of the oral mucosa and that smoking activates the epithelial melanin unit in a non‐specific way. The hypothesis was put forward that in the oral mucosa melanin plays a role as a binder of toxic products such as free radicals and polycyclic compounds. In this way the epithelial melanin unit serves a protective function and prevents tissue damage.
Microbiological and clinical short‐term effects of repeated intracrevicular chlorhexidine rinsings
Authors: Westling Marie , Tynelius‐Bratthall Gunilla 
Published: July 2006

Some bacterial and clinical effects by repeated intracrevicular chlorhexidine rinsings were studied. Ten patients with severe periodontitis were selected. Three pairs of contralateral single‐rooted teeth with pockets > 5 mm were chosen in each subject. Two pockets received chlorhexidine treatment, and the contralateral controls were treated with water. Five ml of a 0.2% aquous solution of chlorhexidine gluconate was applied into the pockets with a syringe during 30s. This procedure was repeated 3 times following intervals of 5 min on two consecutive days. The third pair of pockets served as untreated controls. Microbiological and clinical examinations were carried out twice prior to treatment and 1 and 5 days after treatment. The microbiological parameters comprised dark‐field microscopy examination and counts of all colony forming units (CFU) after anaerobic cultivation. The clinical parameters comprised Gingival Index, Plaque Index, and probing depth in mm.Intracrevicular chlorhexidine rinsings significantly reduced the relative number of suspected pathogens, e.g. spirochetes/motiles, when compared to water rinsings on Day 1, but the differences did not persist on Day 5. No differences concerning the number of CFU's and the clinical parameters were demonstrated, however.
Healing following citric acid conditioning of roots implanted into bone and gingival connective tissue
Authors: Gottlow Jan , Nyman Sture , Karring Thorkild 
Published: July 2006

The aim of the present investigation was to examine if a new connective tissue attachment is established following citric acid treatment of previously periodontitis involved roots, transplanted and placed in contact with gingival connective tissue or bone during healing. Periodontal tissue breakdown was produced around the mandibular third and fourth premolars in six beagle dogs by the placement of cotton floss ligatures around the neck of the teeth. When the destruction of the supporting tissues had progressed to the mid‐root level, the ligatures were removed. Following resection of the crowns, the teeth were root filled and the exposed parts of the roots thoroughly scaled and planed during a flap procedure. Half the number of the teeth were subsequently treated with citric acid at pH1 for 3 min while the remaining teeth were treated with sterile saline for the same period of time. Each root was extracted and implanted into grooves prepared in edentulous areas of the jaws in such a way that the root was embedded to half its circumference into bone, leaving the remaining part to be covered by the connective tissue of the repositioned flap of the recipient site.After a healing period of 2 months, an analysis of histological specimens, obtained from biopsies of the recipient site tissues, disclosed that new connective tissue attachment failed to form on the previously periodontitis involved roots whether or not these roots had been subjected to citric acid conditioning. On the contrary, healing consistently resulted in extensive resorption of the roots. The results indicate that citric acid does not alter the biological ability of bone and gingival connective tissue to induce root resorption.
The effect of beta‐aminoproprionitrile on the periodontal ligament
Authors: Cho Moon‐Il , Garant Philias R. 
Published: July 2006

Administration of Beta‐aminoproprionitrile (B‐APN) to young mice produced a characteristic lesion, the lathyritic body, in the middle region of the PDL. Within these lesions the fibroblasts aggregated to form cell clusters of 10 to 20 cells. The aggregated fibroblasts bordered cell‐free regions of collagenous matrix. Individual fibroblasts maintained cytoplasmic polarity and provided a good model for studying collagen secretion from immobilized fibroblasts.Collagenous matrix appeared to be resorbed in the immediate vicinity of the clustered fibroblasts. 3H‐proline radioautography indicated that labelled collagenous matrix was preferentially lost from the middle region of the PDL of both control and experimental mice. However, the decrease in collagen in the middle region was accentuated by B‐APN treatment and the aggregation of fibroblasts in that zone.
Microbiota of periodontal pockets losing crestal alveolar bone
Authors: Tanner A. C. R. , Socransky S. S. , Goodson J. M. 
Published: July 2006

Three adult subjects were selected with moderate to advanced progressing periodontal destruction and generalized gingival inflammation. Progressive disease sites showed radiographic evidence of crestal alveolar bone loss within the previous three months. Darkfield and cultural microbiological samples were taken from both shallow and deep levels within progressing periodontal pockets and inactive control sites in the same individual.The microbiota at shallow and deep subgingival sites within most pockets was similar. W. recta and gram positive rod Type A, however, were elevated in proportions in deep pocket zones. The darkfield and cultural techniques provided different estimates of proportions of organisms in the same sample zone. The darkfield technique was more sensitive for detection of large and curved motile rods, but cultural techniques provided higher counts of fusiform‐shaped species.Using cluster analysis and multiple linear regression, sites associated with recent bone loss were characterized by higher proportions of B. gingivalis, “fusiform”Bacteroides, and small spirochetes, than inactive sites. Inactive pockets contained similar species to progressive disease sites, but in lower proportions. F. nucleatum was isolated in similar proportions from pockets with evidence of recent disease and inactive sites.
Structure of sub‐ and supragingival dental calculus in human periodontitis
Authors: Ruzicka F. 
Published: July 2006

Mature sub‐ and supragingival dental calculus was collected from 60 adult patients with periodontitis, classified into three groups according to certain clinical criteria. Without prior decalcification, ultrathin sections of specimens embedded in Epon 812 were examined with a Zeiss EM‐9 electron microscope, unstained or stained with uranyl acetate and lead citrate. Sub‐ and supragingival calcification exhibited only the electron diffraction pattern characteristic of hydroxyapatite (HAp) in all specimens which were sectioned. The absence of whitlockite and brushite crystals is discussed.Supragingival calcification was divided into extracellular and intracellular types. The extracellular crystals were of two size classes: large and minute ones. Two types of calcification fronts were found. Intracellular calcification began as minute crystals and could be seen in microorganisms with Gram‐positive and ‐negative cell walls. Extracellular calcification originated within the interbacterial matrix. Subsequently, cell walls of bacteria appeared to calcify. Subgingival calcification was also divided into intra‐ and extracellular types. The extracellular crystals also occurred in two size classes. They very often appeared as small hexagonal platelets in cross sections of the HAp columns. It is suggested that the various forms of crystals were due to differences in the composition of saliva and crevicular fluid. Some differences in subgingival calculus between the three clinical groups are described.