bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphoproliferative response to dento‐gingival plaque sonicate of renal transplant recipients
Authors: Tollefsem T. , Helgeland K. , Saltvedt E.
Published: July 2006

The in vitro lymphocyte blastogenic responses of renal allograft recipients treated with immunosuppressive agents were compared with those of systemically healthy subjects with varying degrees of periodontal disease. The healthy subjects were divided into three groups; Group I showed no bleeding gingival units on gentle probing, Group II comprised persons with gingivitis, while Group III consisted of those with periodontitis. The target group (IS) comprised 11 renal allograft recipients maintained on an azathioprine and corticosteroid regimen. Two other such patients (Group CY) treated with cyclophosphamide and corticosteroids were also evaluated. Total and differential peripheral blood leukocyte counts from the IS group gave mean values within normal ranges. The mononuclear cells from peripheral blood were cultured for five days in a medium supplemented with foetal bovine serum. Triplicate cultures were stimulated with phytohemagglutinin and pokeweed mitogen. The responses of the IS patients and the systemically healthy subjects were not significantly different, whereas cells from the patients treated with cyclophosphamide showed impaired proliferative activity. When cultures were stimulated with a sonicate of dental plaque (DP), cells from the Groups II and III showed a statistically significant higher 3H‐thymidine uptake than did those from the Groups I and IS (p<0.05). The difference between the latter two groups was not statistically significant. The weak blastogenic responses of IS cells to DP antigens may be part of the explanation for the mild gingivitis observed in these patients.
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.
Cell migration in the periodontal ligament of mice
Authors: McCulloch C. A. G. , Melcher A. H.
Published: July 2006

Cell migration and the rate at which cells divide was examined in the periodontal ligament of mouse molars. A pulse injection of 3H‐Tdr was administered, and mice were sacrificed between 1 hour and 60 days after injection. Analysis of radioautographs using labelling index and grain counts demonstrated that the majority of labelled cells divided within 3 days but a measurable population of cells had not divided after 14 days. These cells were G2‐blocked. The labelling index of cells adjacent to alveolar bone increased 8 times within 1 day, indicating that labelled cells had migrated to the bone surface. Migration of cells to the vicinity of the cementum was observed 3 days after labelling. The percentage of labelled cells located within 20μm of one another increased to 40% within 3 days, suggesting clonal proliferation of periodontal ligament cells.
Cell turnover in the periodontium in health and periodontal disease
Authors: Gould T. R. L. , Brunette D. M. , Dorey J.
Published: July 2006

The use of tritiated thymidine labelling given by continuous delivery over long periods by means of an implanted osmotic minipump is a convenient method of accurately determining the rate of cellular proliferation in various tissues, but is especially advantageous for the periodontal ligament (PDL), the fibroblasts of which turn over at an extremely low rate. This technique was used to examine the hypothesis that differences exist between cell turnover in normal hamsters (N.D.) and those which had been placed on a periodontal disease inducing diet (S.S.D.). Turnover rates were then calculated for PDL and epithelial attachment (EA) for N.D and S.S.D animals before and after disease had been induced. No effect of disease was noted for either PDT or EA. However, the technique was sufficiently sensitive to demonstrate a significant effect of age on the turnover of cells in the epithelial attachment.
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.
Immune response and periodontal bone loss in germfree rats immunized and infected with Actinobacillus actinomycetemcomitans
Authors: Taubman M. A. , Yoshie H. , Wetherell J. R. , Ebersole J. L. , Smith D. J.
Published: July 2006

Experiments were performed to determine the effect of delayed‐type hypersensitivity (DTH; cell mediated immunity) on subsequent periodontal bone loss in monoinfected (Actinobacillus actinomycetemcomitans [A actinomycetemcomitans]) gnotobiotic rats. Foot pad swelling reactions to A actinomycetemcomitans sonicate were used to monitor both immediate hypersensitivity and DTH. DTH was present in A actinomycetemcomitans immunized (I) animals when initially challenged with A actinomycetemcomitans. This DTH was maintained throughout the experimental period Sham‐immunized (SI) animals did not show DTH until after 30 days of infection. The cellular infiltrate in the gingiva of immunized animals was relatively more mononuclear than the infiltrate of SI animals Serum IgG antibody to A actinomycetemcomitans was significantly elevated in I compared to SI animals. The relationship between the foot pad swelling and serum antibody levels suggested that an active Arthus type reaction was observed A actinomycetemcomitans injected rats demonstrated an Arthus‐type reaction throughout the duration of the experiment SI animals only showed this reaction 30 days after immunization; the extent of swelling was always less than in the I group. Immunized rats demonstrated significantly elevated horizontal bone loss after infection for 90 days. The data suggest that a “mixed” hypersensitivity reaction to A actinomycetemcomitans occurs in presensitized rats and that the presence of this hypersensitivity can be associated with increased periodontal bone loss.
Vascular changes during the development of the rat gingiva
Authors: de Goes Mario Fernando , de Almeida Oslei Paes , Bozzo Lourenço , Vizioli Mário Roberto
Published: July 2006

Permeability of the dento‐gingival vessels was studied during the development of the gingiva in rats. Groups of animals, aged 19 to 150 days, were injected intravenously with colloidal carbon, and the gingival vessels were observed both macroscopically and microscopically. As the tooth cusps emerged into the oral cavity, vessels labelled with carbon were observed in the connective tissue overlying the tooth and, two to four days later, tracer particles were found in the vessels adjacent to the junctional epithelium. The leaking vessels had a linear pattern beneath the dento‐gingival junction in young animals, while in adult rats these vessels formed loops. In the interdental papilla, labelled vessels were observed initially only in the gingiva adjacent to the distal of the first molars, and two days later also in the gingiva facing the mesial of the second molars. There was a progressive increase in gingival blood vessels labelled with carbon until the rats were 150 days old. The results indicate that the inflammatory process and the increased vascular permeability in the gingiva are initialed during tooth eruption and show quantitative and morphological modifications during the organization of the sulcular and junctional epithelia.
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.
The long‐term effect of chlorhexidine on plaque, gingivitis, sulcus depth, gingival recession, and loss of attachment in beagle dogs
Authors: Tepe J. H. , Leonard G. J. , Singer R. E. , Gray J. A. , Gibberman B. P. , Mulvihill J. E.
Published: July 2006

The long‐term effects of chlorhexidine on plaque, gingivitis, sulcus depth, loss of attachment, and gingival recession in the beagle dog were evaluated in this study. Dogs treated thrice daily with 0.2% chlorhexidine digluconate were found to have significantly less plaque, gingivitis, loss of attachment, and gingival recession than dogs treated similarly with water. The study demonstrates that chlorhexidine is effective in preventing the normal progression of periodontal disease in the beagle dog over a five‐year period.
Ultrastructure of normal and newly formed dento‐epithelial junction in rats
Authors: Mařiaková Z.
Published: July 2006

Standardized periodontal lesions were produced in rats by inserting silk ligatures into the gingival sulcus of the first mandibular molars for three weeks. Ligatures were removed and the tissue left to heal for 10 weeks. The newly formed dento‐epithelial junction was investigated electron‐microscopically and compared with the same structure in control animals with an intact periodontium. No differences were found between the experimental and the control animals. The existence of a sub‐lamina lucida (a substructure of the internal basement lamina) was confirmed, as described previously in monkeys.
The ultrastructural response to loading of the oral mucosa of the vervet monkey
Authors: Grossman E. S. , Austin J. C.
Published: July 2006

The ultrastructural changes occurring within the epithelium of the palate, attached gingiva, tongue, buccal mucosa, and alveolar mucosa of the vervet monkey when a mechanical load was applied to the tissues was examined. The effect of the load was assessed in terms of changes in epithelial cell and nuclear shape, intracytoplasmic structures, cell membrane interdigitation, intercellular space, and changes in the shape of non‐keratinocytes found within the epithelium. Loading produced a flattening of cells and nuclei throughout the epithelium. Intercellular space was reduced, cell membranes were flattened or else underwent increased interdigitation, tonofilaments became functionally oriented, and cytoplasmic vacuolation took place. The mitochondria appeared unchanged on loading. These changes were more marked in the nonkeratinized buccal and alveolar mucosa than in the keratinized palate, tongue, and attached gingiva. A histometric analysis which was carried out on the normal and loaded attached gingiva and alveolar mucosa revealed that the cells and nuclei of both tissue types underwent a significant change in width when loaded. Loading produced no significant change in the diameter of mitochondria in the basal and spinous layers.
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.
A quantitative electron microscope study of desmosomes and hemi‐desmosomes in vervet monkey oral mucosa
Authors: Grossman E. S. , Austin J. C.
Published: July 2006

The distribution and size of hemidesmosomes on the basal cell membrane adjacent to the basement lamina and desmosomes on the spinous cell membranes were compared in the attached gingiva, hard palate, tongue, alveolar mucosa, and buccal mucosa of the vervet monkey. The lengths of the sectioned cell membranes and pooled desmosome lengths were measured on photomicrographs of basal and spinous cells printed at standard magnification. The mean desmosomal length, interdesmosomal distance, and percentage cell membrane occupied by desmosomes was calculated. It was found that the percentage cell membrane occupied by hemidesmosomes was significantly higher in the basal cells of the attached gingiva and palate than in the alveolar mucosa, buccal mucosa, and tongue. In the spinous cell layer the percentage cell membrane occupied by desmosomes and the desmosome length was significantly higher in the tongue, attached gingiva, and hard palate than in the alveolar mucosa and buccal mucosa.
The measurement of interexaminer agreement on periodontal disease
Authors: Fleiss J. L. , Chilton N. W.
Published: July 2006

The statistic kappa is presented as a more appropriate measure of interexaminer agreement than simple percentage agreement scores, because it incorporates an adjustment for the degree of agreement to be expected purely on the basis of chance. When applied to data from an interexaminer reliability study of six variables measuring periodontal pathology, the kappa statistic confirmed and strengthened many of the conclusions drawn in the original paper. In addition, thanks to the use of kappa in the study of other variables, comparisons were possible with the degree of interexaminer agreement attained in clinical medicine and in dental caries.
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.
A photometric test method for the control of gingival recessions
Authors: Tenenbaum H. , Herr P. , Bercy and P. , Klewansky P.
Published: July 2006

The study describs a standardized and reproducible photometric test method for the measurement of gingival recession surfaces. A sample of 45 teeth associated with gingival recessions was selected for testing the control method. The planimetric results suggest a high reliability of the method (p > 0.98) compared to the clinical measurements of the height and the width of the recessions with a graduated periodontal probe.
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.
Connective tissue organization of healthy human gingiva
Authors: Chavrier C. , Couble M. L. , Magloire and H. , Grimaud J. A.
Published: July 2006

Healthy human gingival connective tissue appears to be arranged in two patterns of organization at the ultrastructural level: Pattern I (PI) and Pattern II (PII). PI is a dense pattern of organization mainly constituted of large, dense bundles of thick collagen fibers, whereas PII is a loose pattern of organization, mainly constituted of short, thin collagen fibers mixed with a fine reticular network, especially located under or around basement membranes. Ultrastructural immunoperoxidase labelling of types I, III, and IV collagen demonstrates that gingival connective tissue is made of an intricate pattern of type I and III collagen where type I collagen fibers are preferentially organized in large dense bundles in PI, whereas a fibrous and fibrillar type III collagen network is predominant in PII. Type IV collagen, which does not exist in fibrous or fibrillar form, appears to be the main collagenous component of the basement membranes.
Periodontal ligament stresses in the initiation of occlusal traumatism
Authors: Reinhardt Richard A. , Pao Y. C. , Krejci Robert F.
Published: July 2006

Mechanical stresses in the periodontal ligament which help initiate the lesion of occlusal trauma have been difficult to evaluate. The purpose of this study was to use a mathematical system (finite element analysis) to calculate principal periodontal ligament stresses in primary and secondary occlusal trauma. Maxillary central incisors were modeled in periodontal tissues representing four levels of bone support. Models were partitioned and subjected to three simulated functional loads. Stresses were calculated at multiple nodes in the periodontal ligament adjacent to root and bone. Results showed areas of greatest compressive stress near the alveolar crest and in the apical one‐half of the root for all loads at all bone levels. Stress curves correlated well with the histologic lesion of occlusal trauma. Centric contact loads (P3) consistently produced less ligament stress than protrusive contact (P1). Reduction of alveolar bone height had little effect on the degree of periodontal ligament stress until six millimeters (60%) of bone support had been lost. Finite element analysis provides a convenient model for the study of the mechanical component of occlusal traumatism.
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.
Neutrophil chemotaxis and phagocytosis in juvenile periodontitis
Authors: Ellegaard B. , Borregaard N. , Ellegaard J.
Published: July 2006

Detailed quantitative studies of phagocytosis were performed on purified blood neutrophils isolated from 12 young and 10 adult patients with advanced periodontitis and from 22 age and sex matched controls without periodontitis. Chemotaxis was significantly reduced only in the young patients whereas no difference could be demonstrated between young and adult patients or controls in uptake of opsonized zymosan particles, in the concentration and consumption rate of ATP, in the rate of oxygen consumption and superoxide liberation, or in the exocytosis of β‐glucuronidase and lysozyme during phagocytosis. Serum opsonization was equally effective in the 3 groups. It is concluded that defective chemotaxis in juvenile periodontitis does not originate from defective mobilization of energy in the neutrophils during active movements.
Ultrastructure of freeze‐fractured neutrophil leukocyte membranes in juvenile periodontitis
Authors: Sandholm Leena , Lounatmaa Kari , Saxén Leena
Published: July 2006

Peripheral blood polymorphonuclear leukocytes (PMNs) of eight patients with juvenile periodontitis (JP) and five healthy controls were freeze‐fractured. The ultrastructural features of the split plasma membrane faces were examined with transmission electron microscopy. Aberrations were found in the PMN plasma membrane ultrastructure in three of the eight JP patients. The following changes were found: 1) defect of the cytoplasmic membrane resulting in ruptured remnants of one leaflet on the fracture face of the other, exhibiting fragments on the P‐faces and nodules on the E‐faces; 2) hexagonal or irregular grouping of the intramembranous particles (IMPs); and 3) heterogeneity in the distribution of IMPs with varyingly dense and almost empty areas.
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.
Identification of bacteria in immunopathological mechanisms of human periodontal diseases
Authors: Peković D. D. , Fillery E. D.
Published: July 2006

Serial frozen sections were cut from seventy samples of gingiva of periodontal patients and used for the identification of oral bacteria in immunopathological mechanisms. These mechanisms were identified by sera raised against A. viscosus, A. naeslundii, B. gingivalis, and B. melaninogenicus ss. intermedius; commercial sera against human immunoglobulins and complement; and monoclonal antibodies against T‐cells using a double‐staining immunofluorescence technique. Sections of gingival samples from healthy sites were usually plaque‐free and showed no penetration of bacteria or bacterial antigen or appreciable inflammation. Neither antigenantibody‐complement complexes nor immunocompetent cells could be demonstrated in these healthy tissues. Gram‐stained sections of samples from diseased sites showed large numbers of bacteria and inflammatory cells in gingival plaque and penetration of bacteria into the gingival tissue accompanied by inflammation. Wherever the areas of bacterial colonisation or of antigen penetration were large enough to cut three sequential sections, bacteria and bacterial antigens could be demonstrated in complexes with specific antibody and complement. A unique aspect of the present study was the demonstration that penetrating bacteria were always associated with antibodies and frequently also with complement. A. viscosus, A. naeslundii, and B. gingivalis or their Ags were found in almost equal numbers of gingival samples complexed with specific Abs; B. melaninogenicus ss. intermedius was present in a much lower number of samples. However, A. viscosus was found in larger deposits complexed with specific Abs, i.e. more sections per sample, followed by B. gingivalis. A. naeslundii and B. melaninogenicus ss. intermedius were both found in the lowest number of sections per sample. Similarly. A. viscosus was found in the largest deposits of antigen‐antibody‐complement complexes, followed by B. gingivalis and A. naeslundii. B. melaninogenicus ss. intermedius was not found in complexes with complement. In the gingival plaque and in the gingival tissues all the reactants for a cytotoxic type of immunopathological reaction could be demonstrated. Plasma cells were identified in the tissues mainly in the lamina propria. T‐cells were identified, but only in deeper connective tissues.
Blastogenic responsiveness of human lymphoid cells to mitogens and to homogenates of periodontal pocket bacteria
Authors: Suzuki Jon B. , Sims Tom J. , Singer David L. , Page Roy C.
Published: July 2006

Experiments aimed at demonstrating significant differences in the blastogenic responsiveness of peripheral blood mononuclear cells (PBM) activated using bacterial preparations and pokeweed mitogen (PWM) were performed. The known variables in the in vitro assay system were controlled to the greatest extent possible. A range of cell and activator concentrations, incubation times extending from 3 to 7 days, conical microtest wells, and a labeling procedure which accurately reflects blastogenesis was used. Under these test conditions, cultures of activated patient cells did not differ significantly from activated control cells in counts incorporated, in Stimulation Index, or in incubation time, cell concentration, or activator dose required for maximal blastogenesis, except for cultures activated with LPS and PWM. Responsiveness of cultures of patient cells activated with LPS was significantly lower than that of cultures of control cells (P < 0.01). Cultures from most normal control donors exposed to PWM became maximally activated at 3 days' incubation, while cultures from most patients required 5 to 7 days. Cultures of patient cells did differ significantly (p < 0.05) from control cells in that their spontaneous lymphocyte proliferation was suppressed. These observations indicate that patients with periodontitis may have abnormalities in basic immunologic control mechanisms.
Thiol‐dependent collagenolytic activity in culture media of Bacteroides gingivalis
Authors: Toda K. , Otsuka M. , Ishikawa Y. , Sato M. , Yamamoto and Y. , Nakamura R.
Published: July 2006

Twenty strains of anaerobic bacteria including some oral species from Bacteroides, Eikenella, Fusobacterium, Capnocytophaga, and Actinobacillus were used for the detection of collagenolytic activity in their culture media (supernatants). Organisms were essentially grown in complete anaerobic basal broth, and collagenolytic activities in the culture media were measured using 14C‐acetylated soluble collagen from rat skin. When the enzyme reaction was carried out in the standard reaction mixture for 60 min, very low collagenolytic activities were found in culture media of Bacteroides gingivalis 381, 1021, Bacteroides intermedius 163, K l–8, Bacteroides asaccharolyticus ATCC 27067, and Fusobacterium nucleatum ATCC 25586. However, the activity in the media of all species of B. gingivalis tested was enormously enhanced by the addition of reducing reagents having thiol‐groups such as dithiothreitol, L‐cysteine, etc. This stimulated activity was nearly completely inhibited by some thiol‐blocking reagents. In contrast, these reagents had no effect on the collagenolytic activity in the media of the other anaerobes and in the collagenase preparation of Clostridium histolyticum. These results suggest that B. gingivalis produces thiol‐dependent collagenolytic enzyme which may play an important role in the degradation of collagen fibrils in a reduced environment like the deep gingival pocket.
The effect of oxygen‐derived free radicals on gingival proteoglycans and hyaluronic acid
Authors: Bartold P. M. , Wiebkin and O. W. , Thonard J. C.
Published: July 2006

The effect of a chemically induced oxygen‐derived free radical flux has been studied on extracted porcine gingival hyaluronic acid and proteoglycans as well as on cryostat sections of porcine gingivae. The result of the free radical producing system on hyaluronic acid and the proteoglycans was one of reduction of specific viscosity and molecular size. When frozen sections were subjected to the same oxygen‐derived free radical flux and subsequently stained with Alcian blue, a noticeable decrease in staining intensity was observed when compared to control sections. These results are considered to reflect the in vitro capacity of oxygen‐derived free radicals to depolymerize the two major non‐fibrous extracellular macromolecules of gingivae. It is postulated that such a mechanism may be responsible, at least in part, for the destruction of gingival proteoglycans and hyaluronic acid observed in inflammatory periodontal disease.
A quantitative analysis of connective tissue components in phenytoin‐induced gingival overgrowth in children
Authors: Dahllöf G. , Reinholt F. P. , Hjerpe A. , Modér T.
Published: July 2006

A stereological analysis of connective tissue components in phenytoin‐induced gingival overgrowth in children was performed. The volume density (Vv) of the different components was calculated by point counting on semi‐thin sections of interdental papillae from children (n=12) between 8 and 14 years old. This study shows a statistically significant increase in the non‐collagenous matrix Vv and a corresponding decrease in the collagenous matrix Vv in the phenytoin‐enlarged gingiva compared to controls. These results indicate that the PHT‐induced lesion represents a tissue with an altered composition of the connective tissue.
The influence of the morphological and chemical nature of dental surfaces on the migration, attachment, and orientation of human gingival fibroblasts in vitro
Authors: Pitaru S. , Gray A. , Aubin J. E. , Melcher A. H.
Published: July 2006

The influence of four different dental surfaces, demineralized dentine (DD) and cementum (DC), and nondemineralized dentine (ND) and cementum (NC), on the migration, attachment, and orientation of human gingival fibroblasts (HGF) was tested in an in vitro system. The root surface of porcine teeth was planed using a curette. The cementum was removed from half of the teeth and the roots planed again. Slices of root ∼ 150 μm thick were obtained from the roots. Half of the root slices in each group were partly demineralized in 18% EDTA, pH 7.4. Pairs of root slices were added to each of 20 culture dishes containing 5‐day‐old confluent cultures of HGF. The attachment of HGF to the four types of attachment surfaces (DD, ND, DC, & NC) and the formation of oriented sheets of cells extending between the periphery of the slices and the bottom of the dish were assessed quantitatively after 1, 3, and 6 days of culture. In a second experiment, 12 cultures comprising demineralized and non‐demineralized root slices were examined at 1, 3, and 6 days using SEM. In a third experiment, cultures comprising DC slices were prepared as described and examined for 24 h by time lapse microscopy.

It was found, first, that cells started to migrate and attach to the periphery of the slices immediately following the placement of slices. Cellular bridges extending between the attachment surface and the floor of the dish developed during the first 24 h of culture and gradually increased in number and in size throughout the experimental period. Second, partially‐demineralized surfaces were more effective in stimulating cell migration and attachment and cell orientation than were non‐demineralized surfaces, and demineralized dentine surface were more effective than were demineralized cementum surfaces in this regard. These results further elucidate previous findings regarding the enhancing effect of partial demineralization of dental surfaces on wound healing in vivo and suggest that demineralized dentine may provide the most effective dental surface in this respect.
Fiber system of the facial gingiva
Authors: Garnick and Jerry J. , Walton Richard E.
Published: July 2006

The facial gingival fiber apparatus of four adult squirrel monkeys was evaluated. Oblique histological sections demonstrated predominantly horizontal fibers with interdigitating cemental fibers of variable lengths. This fiber arrangement may result in an efficiently functioning dento‐gingival complex.
A new method for the comparison of bone loss measurements on nonstandardized radiographs
Authors: Jeffcoat M. K. , Jeffcoat and R. L. , Williams R. C.
Published: July 2006

A mathematical algorithm was derived which allows comparison of measurements of bone loss from sequential non‐standardized radiographs. The same three anatomical landmarks were defined on both a reference and an alternate radiograph. These coordinates were used to compute a transformation matrix which mathematically “bent” the alternate radiograph to fit the reference radiograph in 44 pairs of non‐standardized radiographs. Comparison of direct measurements of bone loss in reference and alternate radiographs revealed a mean error of 0.55 mm. This error was significantly reduced to 0.15 mm when direct measurements in reference films were compared to transformed measurements on the alternate radiograph. These data indicate the transformation method may be of value in comparing non‐standardized radiographs.
Prostaglandin activity and sulcular flow in carrageenan‐injected gingiva of the dog
Authors: Yoda W. , Sproat R. , Izutsu K.T. , Siegel I.A.
Published: July 2006

Intragingival injection of one percent carrageenan solution in anesthetized dogs caused an increase in prostaglandin‐like activity in the injected gingiva and a two phase increase in sulcular flow. The first phase was not inhibited by either the prostaglandin synthetase inhibitor indomethacin or the antihistamine pyrilamine. The second phase of increased flow, which was temporally correlated with increased gingival prostaglandin‐like activity, was inhibited by indomethacin, but not by pyrilamine. These results suggest that the increase in gingival sulcular flow in this model of inflammation may be, at least in part, related to increased prostaglandin concentrations.