bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early formation of dental plaque on plastic films
Authors: Brecx Michel , Rönström Anders , Theilade Jorgen , Attström Rolf 
Published: July 2006

This study was designed to gain further information on early plaque formation using a previously described method employing plastic films for the collection of the initial deposits.To prevent the loss of loosely adhering material during processing of dental plaque for microscopic observation, the method was further developed by introducing an agar protection of the deposits formed on plastic films prior to fixation, dehydration and embedding procedures.Four human subjects with healthy gingiva developed microbial plaque during periods of 4 and 8 hours on plastic films applied on the buccal surfaces of premolars and cuspids. After 4 hours the plastic films were covered by a surface coating of an acellular material in or on which bacteria, epithelial cells and leukocytes were observed. The microorganisms were almost exclusively identified as Gram‐positive cocci. The deposit in the 8 hour samples exhibited the same general morphology, but with more cellular components. Bacterial aggregation to each other or to epithelial cells was frequently mediated by filamentous appendages on the bacterial cell walls. The frequent observation of a close association between bacteria and epithelial cells suggests that the latter may play an important role as a vehicle for transporting microorganisms to the solid surfaces in the mouth in the initial stage of plaque formation.
Effect of flap placement and defect size on healing of experimental furcation defects
Authors: Klinge Bjorn , Nilveus Rolf , Kiger Robert D. , Egelberg Jan 
Published: July 2006

Through‐and‐through furcation defects were experimentally created in one group of monkeys (Study 1) and in one group of dogs (Study 2). The effect of reconstructive periodontal surgery using citric acid conditioning of the instrumented root surfaces was studied. Two experimental variables were investigated: (1) variation of the placement and suturing of the flaps and (2) variation of the size of the furcation defects.The results of these studies indicate that adequate postoperative flap coverage of the furcations seems to be critical for successful healing of the furcation defects. Variations in the vertical dimension of the defects seems to play a secondary role. Future studies in experimental animals should evaluate methods which will provide improved post‐operative coverage of the furcation area during healing of furcation defects in human patients.
Classification and prevalences of plaque streptococci after two years oral use of chlorhexidine
Authors: Mikkelsen Lena , Jensen S. Borglum , ScHiøtt C. Rindom , Löe Harald 
Published: July 2006

The purpose of the present study was to examine the influence of two years daily oral use of chlorhexidine (Löe et al. 1976) on the distribution of different streptococcal types in dental plaque. Plaque samples were collected from the molars in 16 persons in the chlorhexi dine group and from 17 control persons having used placebo solution. The samples were homogenized in yeast extract, and dilutions plated on mitis salivarius agar incubated micro aerophilically for 24 hours followed by aerobic storage at room temperature for 24 hours.Colonies of each morphological type present were counted on plates having 30–300 colonies and their number related to the total number. One colony of each type was isolated and identified by biochemical tests. The study showed that 84.8 % of the strains could be classified as S. mutans, S. sanguis, S. mitior, S. milleri, S. salivarius, a group intermediary to S. sanguis and S. mitior, and a group resembling S. milleri, using only five biochemical tests: production of extracellular polysaccharide from sucrose, fermentation of mannitol, raffinose and inulin, and hydrolysis of esculin. In the chlorhexidine group the prevalences of S. sanguis and the group of streptococci intermediary to S. sanguis and S. mitior were higher, and the prevalence of S. milleri plus streptococci resembling S. milleri lower, among the streptococcal flora in dental plaque than those observed in the control group.
Human gingival tissues in culture synthesize three metalloproteinases and a metalloproteinase inhibitor
Authors: Heath Joan K. , Gowen Maxine , Meikle Murray C. , Reynolds John J. 
Published: July 2006

Explants of human gingiva obtained during periodontal surgery and maintained in tissue culture synthesized three metalloproteinases which degraded collagen, gelatin, and proteoglycan respectively. Collagenase and gelatinase were present in both active and latent forms suggesting that collagen degradation was taking place. Proteoglycan degrading activity, however, was present only in the latent form.Human gingival fibroblasts in monolayer culture did not synthesize metalloproteinases, but did produce an inhibitor with properties similar to the purified inhibitor TIMP (Tissue Inhibitor of Metallo‐Proteinases) synthesized by rabbit bones in culture. Human gingival fibroblast inhibitor had an apparent molecular weight of 32,000 on gel filtration and blocked the activity of all three metalloproteinases.These findings indicate that further investigation of the factors that control or modify metalloproteinase and TIMP activity in gingival tissues should help clarify the pathogenic mechanisms responsible for connective tissue loss in periodontal disease.
Histometric analysis of ligature‐induced periodontal defects in beagle dogs‐ evaluation following ligature removalLongitudinal
Authors: Jansen Jan , Van Dijk Johan , Pilot Taco 
Published: July 2006

The aim of the present study was to investigate the sequence of events that takes place in ligature‐induced periodontal defects following removal of the ligature.In eight beagle dogs the dentogingival fibres around six lower premolars (2P2, 3P3, 4P4) were cut to the level of the alveolar bone. Closely adapted copper bands were then cemented around the teeth. After 3 weeks the copper bands were replaced by cotton floss ligatures which were left in place for 11 weeks.The dogs were sacrificed on different dates so that it was possible to analyse defects 3, 7, 15, or 31 weeks after ligature removal. Contralateral defects one week after ligature removal served as controls. Micrographic color slides of the histological sections were analyzed using a Ferranti‐Cetec digitizer.Mean values for loss of attachment in the 15 and 31 weeks specimens were greater than in the control defects, suggesting that apical positioning of the junctional epithelium was irreversible. However, alveolar bone height tended to increase with experimental time, indicating bone repair. In the 15 and 31 weeks specimens junctional epithelium was occasionally found between the root surface and the alveolar boneIt was concluded that the model does not show all the histological characteristics of naturally occurring periodontitis even in those dogs examined 31 weeks after removal of ligatures.
Artificial periodontal defects around incisor teeth of beagle dogs
Authors: Jansen Jan 
Published: July 2006

The aim of the present experiment was to investigate if it is possible to create deep periodontal defects around incisor teeth of beagle dogs with the use of orthodontic elastic bands, to investigate if this method is reproducible and predictable, and to evaluate if such defects possess the histopathological characteristics of naturally occurring periodontitis.In eight beagle dogs the dentogingival fibres around four upper incisors, 3I3 and 2I2, were cut to the level of the alveolar bone. Orthodontic elastic bands were placed in these deepened sulci and removed after 8 weeks. Clinical data (probing depth and gingival recession) were recorded at the start of the experiment, immediately following removal of the elastic bands, and 2, 6, 14, and 30 weeks thereafter. The dogs were sacrificed on different dates so that is was possible to analyse defects histometrically 3, 7, 15, or 31 weeks after elastic removal. Contralateral defects one week after elastic band removal served as controls. Micrographic color slides of the histological sections were analysed using a Ferranti‐Cetec digitizer.Immediately after elastic band removal mean values for probing depth and gingival recession were approximately 5.5 mm and 2.0 mm, respectively. Histometrical assessments revealed a loss of attachment of approximately 3.0 mm.The differences in probing depths between Contralateral defects in the same dog were small indicating rather high reproducibility of the method. Because of wide variations in probing depth and histometrical dimensions between dogs, it was concluded that the present method is not fully predictable.Upon elastic removal values for probing depth decreased with approximately 1.5 mm, the result being a moderately deep defect of around 4 mm. Histometrically there was no evidence that the apical positioning of the junctional epithelium was reversible after elastic removal. However, alveolar bone repair could be demonstrated in the 7, 15, and 31 weeks specimens.It was concluded that because of this bone repair, the present defects do not possess all histopathological characteristics of naturally occurring periodontitis.
Effects of repeated scaling and root planing and/or controlled oral hygiene on the periodontal attachment level and pocket depths in beagle dogs
Authors: Syed S. A. , Morrison E. C. , Lang N. P. 
Published: July 2006

A study was performed to evaluate the effect of initial and/or repeated scaling with or without controlled oral hygiene on the level of periodontal attachment and pocket depth in beagle dogs. The clinical results of this three‐year longitudinal study have been reported previously (Morrison et al. 1979). The purpose of the present report is to present the microbiological results of subgingival plaque samples obtained from selected sites at the conclusion of the study.Eight beagle dogs with moderately developed periodontitis were divided into experimental and control animals. The experimental group received a thorough scaling and root planing at the start of the experiment following which the animals were subjected to daily toothbrushing and rubber cup and pumice prophylaxis every second week for 36 months. Four control dogs were not subjected to any oral hygiene procedures for the entire period of the study. The teeth of two quadrants in each animal of the experimental and control group were scaled and root planed every six months.After three years subgingival plaques from the mesial aspect of the fourth premolar in each of the quadrants of each animal were collected by sterile curettes, processed anaerobi‐cally, and cultured in an anaerobic glove box. Significantly lower total viable colony forming units (CFU) as well as significantly lower anaerobe/aerobe ratios were found in the subgingival plaques of the experimental animals. The total CFU of Bacteroides asaccharo‐lyticus was 25 times lower, and tie proportion of CFU of this organism was nine times lower in the experimental sites when compared with the control sites. Repeated scaling every six months also lowered the total CFU and the proportion of Bacteroides asaccharo‐lyticus in the subgingival plaques of the experimental as well as the control animals. The data suggest that the level of Bacteroides asaccharolyticus as key organisms as well as the anaerobe/aerobe ratio are valuable microbiological parameters in evaluating the efficacy of periodontal therapy.
The identification of lymphoid cell subpopulations in sections of human lymphoid tissue and gingivitis in children using monoclonal antibodies
Authors: Seymour G. J. , Crouch M. S. , Powell R. N. , Brooks D. , Beckman I. , Zola H. , Bradley J. , Burns G. F. 
Published: July 2006

Monoclonal antibodies made against lymphocyte differentiation antigens were used to characterize phenotypically the lymphoid cell subpopulations in sections of human lymphoid tissue and inflamed gingival tissue associated with the deciduous dentition in children. Four monoclonal antibodies designated FMC 1, FMC 4, FMC 7, and UCHT1 were used. These antibodies are specific for B‐cells, p28,33 (la‐like) antigen, a B‐cell subset, and peripheral T‐cells respectively. FMC 1 and FMC 4 positive cells (B‐cells) were found mainly in the secondary follicles while UCHT1 positive cells (T‐cells) were found in the parafollicular areas of human tonsils. Cells in some, but not all, secondary follicles in the tonsils were FMC 7 positive.In the gingival tissue only 12.6 % of the infiltrating cells were FMC 1 positive, 12.2 % were FMC 4 positive, and 4.8 % FMC 7 positive. On the other hand over 75 % of cells appeared to be UCHT1 positive.These results indicate that the majority of inflammatory cells in gingivitis associated with the deciduous dentition in children have the phenotype B‐cell antigen‐/p28,33 (lalike) antigen‐/B‐cell subset antigen‐ and possibly T‐cell antigen+. Such a phenotype is, at least by exclusion, suggestive of T‐cells and as such confirms earlier studies using T‐cell enzyme markers.
Lymphoproliferative response of submandibular nodes to mitogens in experimental gingivitis in dogs
Authors: Yoshie Hiromasa , Yamazaki Kazuhisa , Sawada Jun , Watanabe Tomiei , Hara Kohji 
Published: July 2006

The purpose of the present study was to evaluate the lymphoproliferative response of submandibular nodes cells to stimulation by phytohemagglutinin (PHA), concanavalin A (Con A), and lipopolysaccharide (LPS) following experimental gingivitis in dogs.In 4 dogs of the experimental group, gingival inflammation was induced by cervical ligatures on the left jaw, and the right jaw was kept clean by toothbrushing. In 2 dogs of the control group, toothbrushing was performed throughout. After the weight and lymphocyte number in the submandibular nodes were calculated, the lymphocyte response was determined by the uptake of 3H‐thymidine.The weight and lymphocyte number of the ipsilateral nodes increased 2.2 and 3.7 times, respectively, as compared with the contralateral nodes. There was a higher background proliferation of unstimulated lymphocytes from ipsilateral nodes. The lymphocyte response to lower PHA concentration from ligated side lymphnodes significantly increased compared to that from contralateral nodes. It is suggested that the plaque accumulation and the intensive gingival inflammation considerably influence lymphocytes in the submandibular nodes.
A longitudinal study into the depth of the clinical gingival sulcus of human canine teeth during and after eruption
Authors: Smith Roger G. 
Published: July 2006

The depth of the healthy clinical gingival sulcus was investigated in 32 school children by measuring with a flexible rule the sulcus depth of 43 erupting permanent canine teeth. Crown height and the distance to occlusion were measured on casts. One third of the subjects were studied formore than a year, the longest period being 109 weeks. Initial measurements of sulcus depth, before any teeth had reached occlusion, were in the 4.0−13.0 mm range. Final measurements, 17 teeth then being in occlusion, were in the 1.5−6.5 mm range.The sulcus depths of 57 adjacent occluding teeth remained in the 0.5−4.5 mm range.For teeth having a crown height of up to 2 mm when first seen, measurements of sulcus depth and crown height were pooled about monthly intervals. Curves plotted from the means of these values showed a generally smooth increase in crown height and similar decrease in sulcus depth, maximal early in eruption, although no two teeth behaved identically.
Neutrophil chemiluminescence in response to Fusobacterium nucleatum
Authors: Passo Samuel A. , Syed Salam A. , Silva Joseph 
Published: July 2006

During the interaction of bacteria or other particles with neutrophils, oxygen consumption is increased, and unstable reduction products are produced. Chemiluminescence is the light energy produced in the neutrophil by the generation of unstable oxygen radicals. These oxygen radicals are thought to be important in the destruction of bacteria as well as host tissues. Therefore, we wanted to investigate the ability of Gram‐negative plaque bacteria to stimulate neutrophil chemiluminescencein vitro.The major groups of bacteria examined wereFusobacterium, Bacteroides, Capnocytophaga. Selenomonas. and Trcponema. Of these bacteria,Fusobacterium nucleatumhad by far the greatest ability to stimulate neuirophil chemiluminescence in the absence of serum. Our results suggest that stimulation of neutrophil chemiluminescence byF. nucleatumis mediated by a protein moiety on the bacterial cell surface. This conclusion is supponed by experiments demonstrating significant inhibition of neuirophil chemiluminescence by heat, 2% formalin, or trypsin pre‐treatment ofF nucleatum. Also, neutrophil chemiluminescence was stimulated in a similar fashion with intactF. nucleatumonly by the cellassociation centrifugation pellet of sonicatedF. nucleatum. The monosaccharide D‐galactose. which is a component of erythrocyte glycoproteins andF. nucleatumlipopolysaccharide. caused significant inhibition of neutrophil chemiluminescence at 100 mM final concentration. The unusual and pronounced ability ofFusobacterium nucleatumto stimulate neuirophil chemituminescence in the absence of serum might be important in the pathogenicity and/or host defense in periodontal disease.
Effects of force application on periodontal blood circulation
Authors: Gaengler Peter , Merte Knut 
Published: July 2006

The different structure and function of the systemic circulation and microcirculation in the gingiva and in the periodontal ligament in rat incisors has been demonstrated by vital microscopy. A previously developed, standardized vital microscopic technique was applied in order to assess the effects of horizontal force application to the tooth on blood circulation. In narcotized animals, the incisors were prepared for vital microscopic observation either of the periodontal ligament or gingiva, using tooth loading with forces ranging from 30 to 500 mN. The force was applied as short, intermittent forces at 5 to 30 s and as a continuous force for 10 to 180 min.The results revealed circulatory changes which were different in the periodontal and gingival vessels. Both compression and tension in the periodontal ligament led to ischemic areas beginning in the vessels and capillaries (30 mN) and ending with the arteries (100 mN).After continuous force application (60 min, 100 mN), the periodontal vessels showed irreversible thrombosis. Neither short, intermittent forces nor continuous force application had an effect on gingival blood circulation.
Inhibition of plaque formation in humans by octenidine mouthrinse
Authors: Patters M. R. , ÅNerud K. , Trummel C. L. , Kornman K. S. , Nalbandian J. , Robertson P. B. 
Published: July 2006

Octenidine, a new bispyridine antimicrobial compound, has significant antiplaque activity in animals. The present study was designed to assess the effectiveness of this agent in inhibiting plaque formation in humans. Sixty males (age 22–36 years) were randomly assigned 4 formulations which included 1) 0.1% octenidine in vehicle, 2) 0.1% octenidine in aqueous solution, 3) 0.05% octenidine in vehicle, and 4) vehicle only. After establishment of minimal levels of plaque and gingivitis, each subject rinsed twice daily under supervision with his assigned test agent. Over the next seven days, the subjects were not permitted any other means of tooth cleaning. Plaque accumulation was measured daily and gingival fluid and stain levels determined on days 0 and 7.Analysis of the data showed that both formulations of 0.1% octenidine almost completely inhibited plaque formation over the 7 day period. The vehicle had no effect on the agent's activity. The 0.05% concentration allowed some plaque accumulation, but all octenidine groups had significantly less plaque than the control group. Gingival fluid flow was significantly lower in all octenidine groups than in the control group. Tooth stain increased in all groups using the agent but remained unchanged in the group using the vehicle alone.Results of this short term clinical trial suggest that octenidine may be a useful topical antiplaque agent.
New connective tissue attachment in beagles with advanced natural periodontitis
Authors: Bogle Gary , Garrett Steve , Crigger Max , Egelberg Jan 
Published: July 2006

A pilot study using advanced, natural periodontitis in beagle dogs was performed to determine the possibility of achieving periodontal regeneration to an extent that would bring the attachment back to the original level at the cemento‐enamel junction. Nine mandibular premolars in two beagles were treated with a mucoperiostal flap procedure including citric acid conditioning of the root surfaces and coronal placement and suturing of the flaps.Histologic examination of buccal and lingual root surfaces demonstrated new connective tissue attachment including the formation of new cementum back to or near the cemento‐enamel junction in most specimens. The mean epithelial migration apical to the cemento‐enamel junction amounted to only 0.3 mm. The formation of new crestal alveolar bone, however, was limited. The histological analyses of the furcation areas showed new connective tissue attachment in six of the nine specimens.The result indicates that it is biologically possible to obtain new connective tissue attachment up to the original level of attachment at the cemento‐enamel junction following treatment of advanced natural periodontitis in beagle dogs. It seems to be possible to accomplish this connective tissue attachment not just in isolated areas, but at several circumferential locations on the teeth as well.
A freeze‐fracture study of the periodontal ligament of the rat
Authors: Cho Moon‐Il , Garant Philias R. 
Published: July 2006

Fibroblasts of the rat periodontal ligament were studied in situ by the freeze‐fracture technique. Large surfaces of the protoplasmic and extracellular faces of the cell membrane as well as, the membranes of the RER, Golgi apparatus, and other cytoplasmic organelles were viewed at the ultrastructural level. Intramembrane particles representing membrane proteins were visualized, and their concentration in various membranes measured.Features of the fibroblast cell surface appearing as rough patches were interpreted to represent areas of possible cell‐to‐matrix interaction. The use of the freeze‐fracture technique in further studies of PDL fibroblast‐matrix contact is discussed.
The effect of Octapinol on dento‐gingival plaque and development of gingivitis
Authors: Attström R. , Matsson L. , Edwardsson S. , Willard L.‐O. , Klinge B. 
Published: July 2006

Octapinol, a compound which in previous studies has been shown to reduce plaque formation in vitro and to reduce gingivitis in vivo in dogs, was studied with regard to its effect on plaque formation and gingivitis in man.The study was divided in two parts. In the first, 24 dental hygiene students were divided into 4 groups of equal size and starting from a plaque‐free base line were treated with 0.1–1.0% w/v aqueous solutions of Octapinol applied daily for 4 days onto the teeth on one side of the jaw while the contralaterial side was treated with a placebo solution. In the second study, 7 students starting from a plaque‐ and gingivitis‐free base line applied a 1.0% solution daily to all teeth for a 3‐week period during which time no mechanical oral hygiene was allowed. After a period of resumed oral hygiene another 3‐week period of no oral hygiene followed during which a placebo solution was applied in a similar fashion.In the first study 0.5 and 1.0% concentrations of Octapinol significantly reduced the plaque formation during the 4‐day test period while the effect of lower concentrations was less prominent.In the 3‐week experiment using a 1% Octapinol solution only minor development of plaque and gingivitis was noted during the test period while rapid accumulation of plaque and marked gingival inflammation occurred during the control period.