bluuebunny/crossref_metadata_2025 huggingface dataset:
Root resorption potentials of granulation tissue from bone and flap connective tissue
Authors: Aukhil I. , Greco G. , Suggs C. , Torney D.
Published: July 2006

The present study was designed to examine the early phases of healing following root implantation in an attempt to compare the potentials of granulation tissue from bone and flap connective tissues to induce root resorption. Three adult beagle dogs with advanced periodontal disease were used and teeth 1P1, 2P2, 4P4, 1M1, and 3I3 were extracted to provide implantation sites. Eight weeks later, the root canals of the remaining premolars were filled with guttapercha. Using a flap procedure, the exposed root surfaces were thoroughly planed and the crowns were resected. The roots were then extracted and implanted in grooves prepared in edentulous areas with half the circumference of the root lying in the osseous groove and the other half of the root lying in contact with connective tissue of the mucoperiosteal flap. On one side of the mouth, the planed root surfaces were conditioned with citric acid for 3 minutes before implantation. Histologic sections cut in the transverse axis of the roots were evaluated at 2 wk (non‐acid treated) and 3 wk (acid‐treated) after implantation. Extensive root resorption and ankylosis were seen on the bone side of the acid‐treated (3 wk) and non‐acid treated (2 wk) roots. On the flap connective tissue side, connective tissue fibers were seen lying parallel to the root surface and resorption, when present, was minimal and usually confined to that part of the root close to the margins of the groove in bone. The results suggest that root resorption primarily originates from granulation tissue derived from bone. The potential of the flap connective tissue to induce root resorption is either less or delayed compared to the connective tissue derived from bone.
Fibronectin in saliva and gingival crevices
Authors: Tynelius‐Brattitall Gunilla , Ericson Dan , Araujo Helena Maria
Published: July 2006

The aims of this study were to determine if fibronectin is present in gingival crevices and in unstimulated or stimulated whole, parotid, and submandibular/sublingual salivas. Eight subjects with healthy gingiva were selected. Two identical examinations with an interval of at least 2 weeks were performed. The examinations included collection of crevicular material and different salivas, with secretion rates recorded. Blood samples were taken and the concentration of plasma fibronectin was used as a positive control. The presence of fibronectin was studied by an ELISA assay. Fibronectin was found in whole saliva and in submandibular/sublingual saliva but could not be demonstrated in parotid saliva. Fibronectin was also found in crevicular material and in plasma. There was no statistically significant difference between the concentration of Fibronectin per μg protein in plasma compared to crevicular material. The amount of fibronectin, expressed as μg/ml. of the different salivas varied between the two examinations and the largest concentration was most often found in unstimulated whole saliva. When the secretion rate was taken into consideration, there were variations between the two examinations and the largest output of fibronectin over time was seen in stimulated whole saliva.
Quantitative measurement of periodontal bone changes by digital subtraction
Authors: Vos M. H. , Janssen P. T. M. , van Aken J. , Heethaar R. M.
Published: July 2006

The use of an aluminium reference object in radiographical studies permits quantification of periodontal bone changes. A digital subtraction techninque was developed for this purpose. To obtain optimal performance, two corrections have to be applied on the image: one to correct for systematic inhomogeneities such as the Heel‐effect and one to correct for film and development inhomogeneities. With an image processing system these and other necessary manipulations can be carried out easily and quickly. The method was tested on a series of radiographs of phantoms with inserted aluminium cylinders. The determined volumes corresponded well with the actual volumes within the system error. This error was found to be proportional to the surface of the inspected area (0.054 mm1/mm2) . Hence, in longitudinal studies, the method promises to be an accurate and quantitative tool, and it may be able to replace subjective and non‐quantitative observer studies.
Synthesis of cementum‐like tissue in vitro by cells cultured from bone: a light and electron microscope study
Authors: Melcher A. H. , Cheong T. , Cox J. , Nemeth E. , Shiga A.
Published: July 2006

Cells obtained from calvariae of fetal rats, human gingival connective tissue and periodontal ligament of rat molars were each co‐cultured in vitro with non‐demineralized and partly demineralized root slices in nutrient medium containing 50 μGg/ml ascorbic acid and 10 mM B‐glyeerophosphate, in order to determine whether the root slices could affect the phenotype expressed by the cells. The cultures were examined by light and transmission electron microscopy. Nodules of bone‐like tissue, resembling those previously described by others, were observed in the multilayers of cells obtained from rat calvariae. but not in the multilayers of gingival and periodontal ligament cells, after 30 days of culture. Calvaria cells associated with the root slices produced tissues exhibiting ultrastructure that resembled that of bone or cellular cementum. acellular cemenlum and afibrillar cementum in vivo when examined after the same length of time. The tissues were never found in cultures of gingival fibroblasts or periodontal ligament cells. These observations suggest, first, that cells derived from bone can express in vitro the phenotype for the cementums; second, that cells obtained from human gingival and rat periodontal ligament do not do so when cultured under similar conditions; and third, the possibility that the osteoblasts, cementoblasts and their progenitors that are found in the periodontal ligament could, at least in part, have their origin and migrate there from the endosteal spaces of the alveolar process.
Human gingival Langerhans cells in health and disease
Authors: Newcomb G. M. , Powell R. N.
Published: July 2006

Epithelial Langerhans cells in samples of healthy and diseased gingival tissue were studied using ATPase histochemistry and the monoclonal antibodies OKT6 and anti HLA‐DR. In healthy gingiva Langerhans cells were seen in both oral and sulcular epithelium; they were generally positioned in the basal layers. No Langerhans cells were seen in junctional epithelium. In diseased tissue there was a large increase in the number of Langerhans cells in both oral and sulcular epithelium with many more being situated in the stratum spinosum. There was an increase in the expression of the Class 2 antigen, HLA‐DR, and morphological polarization occurred with dendrites preferentially orientated towards the surface. No Langerhans cells were seen in the pocket lining epithelium of periodontally diseased gingiva.
Immunohistochemical investigation of the presence and distribution of cementum‐associated lipopolysaccharides in periodontal disease
Authors: Hughes F. J. , Smales F. C.
Published: July 2006

An immunohistochemical technique was used to investigate the distribution of cementum‐associated LPS in 14 human teeth extracted because of periodontal disease. Autologous affinity purified anti‐LPS antibodies were obtained against a preparation of oral LPS types bound to an epoxy‐activated Sepharose 6B‐polymyxin B column. The concentration of immunoglobulin classes G. M and A in the prepared sera was assayed by rocket immunoelectrophoresis and the reactivity of the sera was checked using an ELISA to the LPS preparation. Ground sections of the teeth were prepared and incubated with prepared autologous antiserum, followed by detection of Ig binding by a rabbit PAP system. LPS was detected on cementum which had been previously exposed to a periodontal pocket and extended to within I mm of the previous level of connective tissue attachment. LPS was only detected on the surface of cementum and on no occasion was LPS seen penetrating into sub‐surface cementum. These results suggest that extensive removal of sub‐surface cementum is not necessary in order to render root surfaces free of bacterial endotoxins during root planing procedures.
Collagenase and collagenase inhibitor activities in crevicular fluid of patients receiving treatment for localized juvenile periodontitis
Authors: Larivée Jacinthe , Sodek and Jaro , Ferrier Jack M.
Published: July 2006

Collagenolytic activity was monitored in crevicular fluids of 3 patients receiving treatment for localized juvenile periodontitis (LJP) and in 3 control, clinically healthy patients to study relationships between mammalian collagenase and disease activity. It was found that tissue collagenase activity initially was significantly higher in diseased patients compared to controls, but that in II of 13 diseased sites the activity decreased substantially following clinical treatment. In control sites, active collagenase was generally low or absent. Latent collagenase concentrations tended to remain high in diseased sites and in sites with gingival inflammation. Collagenase inhibitor activity was found only in clinically healthy sites sampled from both control subjects and LJP patients throughout the experiment, and in diseased sites following various phases of treatment. The collagenolytic activity observed was typical of mammalian collagenase in that the primary degradation products of collagen were 3/4‐ and 1/4‐fragments. However, additional specific fragmentation of native collagen 3/4‐fragments was also observed, which could be attributed to a novel collagenolytic activity generally present in crevicular fluid in a latent form. The results of this study suggest that the determination of active collagenase and collagenase inhibitor in crevicular fluid might be useful in assessing both the disease status of periodontal tissues and the efficacy of clinical treatment.
Progression of untreated periodontitis as assessed by subtraction radiography
Authors: Hausmann E. , Dunford R. , Wikesjö U. , Christerssion L. , Mchenry K.
Published: July 2006

Crestal interdental bone in 15 untreated subjects with periodontitis was monitored over a 6‐month period. Whereas 9% of interdental sites exhibited bone loss, 4% exhibited bone gain. The sites of bone loss were found in 9 of the subjects. 2 subjects demonstrated gain as well as loss, with I subject demonstrating only gain. Pocket depth, gingival index and plaque index values were of little value in predicting bone change seen by subtraction. Results from subtraction radiography are consistent with exacerbation and remission at crestal alveolar bone sites in untreated periodontitis patients.
A comparison of mouthrinses containing two concentrations of chlorhexidine
Authors: Segreto V. A. , Collins E. M. , Beiswanger B. B. , de La Rosa M. , Isaacs R. L. , Lang N. P. , Mallatt M. E. , Meckel A. H.
Published: July 2006

A 3‐month clinical trial was conducted to compare the effects of two concentrations of a chlorhexidine mouthrinse on gingivitis and plaque accumulation. Six hundred (600) adults were divided into three treatment groups matched for age, sex, and initial gingivitis severity. Following a thorough examination and prophylaxis at baseline, subjects were given a mouthrinse containing either 0.12% or 0.20% chlorhexidine gluconate or a placebo mouthrinse. Subjects were evaluated after 6 weeks and 3 months of mouthrinse use. After 3 months, both chlorhexidine groups showed significantly less gingivitis and plaque than the placebo group. The group using the 0.12% chlorhexidine gluconate mouthrinse demonstrated 27–27 % less gingivitis occurrence and 28–28% less gingivitis severity than the placebo group. The 0.12% chlorhexidine gluconate group also had 48–48% less gingival bleeding and 36% less plaque than the placebo group. There were no significant advantages for the 0.20% mouthrinse over the 0.12% mouthrinse. It is therefore concluded that a 0.12% chlorhexidine gluconate mouthrinse offers the same clinical benefits as a 0.20% chlorhexidine gluconate mouthrinse.
Six‐month study of the effects of a chlorhexidine mouthrinse on gingivitis in adults
Authors: Grossman E. , Reiter G. , Sturzenberger O. P. , De La Rosa M. , Dickinson T. D. , Flrretti G. A. , Ludlam G. E. , Meckel A. H.
Published: July 2006

The effects of a chlorhexidine gluconate mouthrinse on plaque and gingivitis were studied among 430 adults in a six‐month clinical trial. Subjects were divided in two comparable treatment groups matched for age, sex, and initial gingivitis severity. Following a thorough oral prophylaxis, they were instructed to rinse twice a day for 30 seconds with 15 ml of a 0.12% chlorhexidine gluconate mouthrinse or a placebo mouthrinse. After three and six months of mouthrinse use, the chlorhexidine group had significantly less gingivitis, gingival bleeding, and plaque accumulation compared to the placebo group. As expected, accumulation of dental calculus and extrinsic dental stain increased in the chlorbexidine group. No significant differences in adverse oral soft tissue effects were observed between the two groups.

Since use of oral antimicrobial agents has been reported to produce tooth and tongue stain, gingivitis examinations were done with and without tooth covers to eliminate the potential for examiner bias. Comparable reductions in the Gingival Index scores and gingival bleeding were obtained when the evaluations were conducted with or without the tooth covers.

It was concluded that a 0.12% chlorhexidine gluconate mouthrinse can provide an important adjunct to the prevention and control of gingivitis when used with regular personal oral hygiene procedures and professional care.
Assessment of susceptibility of plaque bacteria to chlorhexidine after six months' oral use
Authors: Briner W. W. , Grossman E. , Buckner R. Y. , Rebitski G. F. , Sox T. E. , Setser and R. E. , Ebert M. L.
Published: July 2006

Changes in the susceptibility of plaque bacteria to chlorhexidine treatment were investigated by determining the minimum inhibitory concentration (MIC) of chlorhexidine on two kinds of bacteria commonly found in supragingival plaque. Streptococci and actinomyces were isolated from plaque samples collected from subjects participating in a clinical trial comparing a 0.12% chlorhexidine gluconate mouthrinse to a placebo mouthrinse. The isolates were inoculated onto media containing varying concentrations of chlorhexidine to determine the MIC of chlorhexidine during the six‐month treatment period and three months after cessation of treatment. While significant differences in the sensitivity of these two bacterial strains to chlorhexidine were seen sporadically, no consistent pattern of resistance emerged. It was concluded that prolonged use of a 0.12% chlorhexidine gluconate mouthrinse did not alter the composition of the oral microflora toward organisms less sensitive to chlorhexidine. This conclusion was further supported by the clinical findings in this trial that showed chlorhexidine's effects on plaque and gingivitis indices were maintained throughout the six‐month treatment period. Three months after the mouthrinse was discontinued, the MIC's of chlorhexidine on isolates from placebo‐treated and chlorhexidine‐treated subjects were the same as pretreatment values. Thus, no residual change in resistance was observed nor were there any adverse changes in the microbial profile.
Chlorhexidine digluconate–an agent for chemical plaque control and prevention of gingival inflammation
Authors: Lang NiklausP. , Brecx Michel C.
Published: July 2006

In selecting antimicrobial agents for the prevention and treatment of periodontal diseases, the following factors should be considered: 1. Specificity, 2. Efficacy, 3. Substantivity, 4. Safety, 5. Stability. Using these criteria, several antibiotics and antiseptics have been evaluated in recent years for chemical plaque control. While antibiotics are mostly used under a specific plaque hypothesis, antiseptics are more suitable for a non‐specific plaque concept. Several antiseptics hinder plaque formation or even break up old plaque. For example, quaternary ammonium compounds, combinations of metal ions with pyrimidines or with fluorides, phenolic compounds, and plant alkaloids have yielded a plaque reducing effect of 20–20% and have also delayed slightly the development of gingivitis. Years of documented research have established that chlorhexidine digluconate is safe, stable, and, owing to its great substantivity, effective in preventing and controlling plaque formation, breaking up existing plaque, and inhibiting and reducing the development of gingivitis. In studies of 6 months and longer, chlorhexidine has been shown to reduce gingivitis by 50–50% compared to a placebo control. Chlorhexidine is the most effective and most thoroughly tested antiplaque and antigingivitis agent known today.
Gingival fluid levels of acid and alkaline phosphatase
Authors: Binder T. A. , Goodson J. M. , Socransky S. S.
Published: July 2006

Microtiter assays for acid and alkaline phosphatase levels in gingival fluid (GF) have been evaluated for their use as possible indicators of periodontal disease activity. Alkaline phosphatase concentration was shown to be positively associated with periodontal disease activity, while acid phosphatase showed no relation to disease activity. When a series of timed gingival fluid samples was taken from several sites in one subject's mouth, reproducible differences in volume, alkaline phosphatase concentration, and total acid phosphatase were found between the first and subsequent samples. Acid and alkaline phosphatase are presented as models of how substances can enter the periodontal pocket by different routes.
Immunohistochemical study of types I, III and IV collagen in fibrosis of diseased gingiva during chronic periodontitis: A light and electron microscopic study
Authors: Chavrier C. , Couble M. L. , Hartmann D. , Grimaud J. A. , Magloire H.
Published: July 2006

The distribution of type I, III and IV collagen and their ultrastructural organization have been studied in fibrotic gingival connective tissue of patients with longstanding cases of chronic periodontitis. The use of an immunofluorescent procedure has shown that the diseased connective tissue was made up of both type I and type III collagen. Type I collagen was strongly fluorescent and appeared to be the main gingival collagenous component, equally distributed in all layers of the tissue, whereas type III collagen was weakly fluorescent and mostly found in gingival papillae, but not around blood vessels. Standard electron microscopy and immunolabelling using the peroxidase procedure have shown that the large and dense bundles of type I collagen of P1, which is the main pattern of organization of the gingival connective tissue, were infiltrated by small bundles of microfilaments (10–15 nm) identified as the fibrillar form of type III collagen. However, in PII, the second pattern of organization of the gingival connective tissue, type I collagen fibers were predominant and gave a fibrous feature to this area. Type IV collagen was exclusively located in the thickened, degraded Lamina densa of basement membranes.
Large melanosome complexes in the human gingival epithelium
Authors: Anders Hedin C. , Larsson Äke
Published: July 2006

The morphology of melanosome complexes (MC) in gingival epithelium from smokers and non‐smokers was studied by electron microscopy. The cross‐cut diameter was measured on 770 complexes within keratinocytes. In pigmented smokers and non‐smokers the average diameter was between 0.51 and 0.63 μm, which is larger than those observed in clinically non‐pigmented non‐smokers and compared to those previously reported from clinically non‐pigmented Caucasians. The diameter of 95% of all complexes was less than 1.0 μm, but 40 large melanosome complexes (LMC) were also found. LMC could reach a diameter of 3.2 μm, and contain more than 100 melanin granules. The presence of LMC in oral mucosa has not been reported previously, but they have been observed in pigmented human skin disorders. Our finding of LMC in the gingival epithelium of pigmented individuals among smokers and non‐smokers, but not in non‐pigmented non‐smokers, indicate that this entity is related to melanosome packaging in situations of high melanin production and not necessarily only to pathological conditions.
Increased serum IgG antibodies reactive with lipoteichoic acids in subjects with gingivitis
Authors: Monefeldt Kari , Tollefsen T. , Assev S. , Rølla G.
Published: July 2006

The aim of the present study was to assess serum antibodies reactive with lipoteichoic acids (LTAs) in test panels with and without gingivitis. LTA‐rich preparations were obtained from Streptococcus mutans and from Staphylococcus aureus cells. Serum IgG antibodies to those LTAs, and to commercially available lipopolysaccharide (LPS) from Escherichia coli strain 055:B5 were measured in enzyme‐linked immunosorbent assays (ELISA). The LPS was included as a negative control. Serum antibodies reactive with LTAs showed a significant (p<0.05) age‐dependent rise in young people (aged 4 to 24 years), and then leveled out. Ten days experimental gingivitis was induced by means of frequent sucrose rinses in 10 volunteers (all 19‐yr‐old). The mean serum antibody levels to the LTA‐rich extracts increased 3‐ to 4‐fold during the test period, whereas the mean antibody level to LPS remained unchanged. Ten periodontally healthy adult persons were matched for age (3‐yr intervals) and teeth present (± 3 teeth) with 10 adult subjects with chronic ginvititis, but no alveolar bone loss. The mean age was about 50 yr. The chronic gingivitis group showed statistically significant, i.e. 4‐ to 5‐fold higher antibody levels reactive with the LTAs. The corresponding difference in anti‐LPS levels was insignificant. Dental plaque thus triggers significant systemic antibody responses to LTAs.
The prevalence of advanced loss of periodontal attachment in two New Mexico populations
Authors: Ismail Amid I. , Eklund Stephen A. , Striffler David F. , Szpunar Susan M.
Published: July 2006

This paper describes the prevalence of destructive periodontal disease, in two samples of New Mexico adults, examined in two separate studies 26 years apart, by analyzing the occurrence of advanced loss of periodontal attachment (7.0 or more mm) in relation to selected dental and social factors. The first group comprised 1976 dentate adults aged 17–46 yr who were examined in 1958–59. The second study, conducted in 1984, included 372 dentate adults aged 27–74 yr. In the 1958 study, the prevalence of advanced loss of attachment was significantly associated with age, gender, race, education, plaque scores, and calculus scores. In 1984, the prevalence of advanced loss was significantly associated with age, education, and the presence of plaque. The analysis of loss of periodontal attachment data from both studies showed that 0.3 and 1.5% of all teeth present in the mouth in persons examined in 1958 between the ages of 17–26 and 27–46 yr, respectively, had advanced loss of attachment. In the 1984 sample, 1.5 and 6.7% of the 12 tooth sites examined in persons 27–6 and 47–74 yr had advanced loss of periodontal attachment, respectively. These observations are in agreement with recent epidemiological studies of the prevalence and distribution of advanced loss of periodontal attachment.
Preparation and characterization of human gingival cells
Authors: Stoufi Eleana D. , Taubman Martin A. , Ebersole Jeffrey L. , Smith Daniel J.
Published: July 2006

A procedure was developed for the preparation of single cell suspensions from gingival and periodontal tissues using collagenase digestion followed by gentle mechanical disruption. The procedure was evaluated on rat gingival tissues. One‐hour incubation was found to produce the greatest number of cells with the highest viability, and the largest recovery of mononuclear cells. Collagenase did not appear to effect recovery, viability or B cell surface markers on human peripheral blood cells. Human gingival and periodontal tissues were obtained from 35 patients: 20 with adult periodontitis; 8 with juvenile periodontitis; 7 with normal gingivae or chronic gingivitis. Scaling, followed by probing measurements and then surgery of the affected sites was routinely performed. In single cell suspensions from tissue obtained from surgery, significantly fewer mononuclear cells were recovered from the tissues of normal/chronic gingivitis patients than cells/mg of tissue recovered from adult periodontitis or juvenile periodontitis groups. The maximum contribution of blood mononuclear cells to the gingival cells averaged 0.5+0.2%. This method is useful for recovering gingival (periodontal) cells for phenotypic and functional studies.
Black‐pigmented Bacteroides associated with broken‐mouth periodontitis in sheep
Authors: Frisken K. W. , Tagg J. R. , Laws A. J. , Orr M. B.
Published: July 2006

Samples of subgingival plaque were obtained from healthy and broken‐mouth periodontitis‐affected sheep. Deeper pockets were found in affected sheep and these were associated with increased levels of asaccharolytic, black‐pigmented Bacteroides (BPB) species, including trypsinpositive BPB similar to B. gingivalis. It is suggested that these organisms could have a similar role in the pathogenesis of periodontal disease in sheep to that proposed for BPB in certain human periodontal diseases.
Nature of periodontal diseases: Assessment and diagnosis
Authors: Kornman Kenneth S.
Published: July 2006

The assessment and diagnosis of periodontal diseases has become an active and controversial area of research which incorporates both new technologies and new concepts. Previous efforts have demonstrated the potential value of diagnostic testing in differentiating different diseases, in evaluating disease progression, and in monitoring the response to therapy. A few studies have even shown promise in predicting the response to therapy. Some of this work has incorporated proven diagnostic principles which allow a comparison between techniques. It is clear, however, that future work would benefit from an increased incorporation of these diagnostic principles and a recognition of the value of a sequential use of tests. Much work remains and many questions cannot be adequately answered at this time, but we should not lose sight of the great progress which has been made in the area of assessing and diagnosing periodontal diseases.
Nature of collagenolytic enzyme and inhibitor activities in crevicular fluid from healthy and inflamed periodontal tissues of beagle dogs
Authors: Kryshtalskyj Eugene , Sodek Jaro
Published: July 2006

We have previously described the occurrence of collagenolytic enzyme activity in crevicular fluids from beagle dogs in which experimental conditions of gingivitis and periodontitis had been induced (Kryshtalskyj, Sodek & Ferrier 1986). In general, active collagenase activity was demonstrable in fluids from periodontitis sites, whereas in control and gingivitis sites various levels of latent collagenase and collagenase inhibitor activity were present. Analysis of the collagen digestion patterns by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) has shown that crevicular fluid samples with low collagenolytic activity generated ¾‐α and ¼‐α collagen fragments, typical of vertebrate collagenase. However, higher collagenolytic activity associated with periodontitis sites produced further degradation of the native collagen substrate. This activity was characterized by specific degradation products migrating between the ¾‐α and ¼‐α fragments. Similar digestion patterns are generated by enzymes in crevicular fluid from periodontitis sites in humans and by partially purified collagenase from osteoblastic cells (Otsuka, Sodek & Limeback 1984), but not by bacterial collagenase. Analysis of plaque, crevicular cell debris, saliva and serum indicated that the collagenolytic activity is derived from connective tissue and/or inflammatory cells, whereas collagenase inhibitor could also be derived from saliva and serum.
The biocompatibility of hydroxyapatite implanted in the human periodontium
Authors: Ogilvie A. , Frank R. M. , Benqué E. P. , Gineste M. , Heughebaert M. , Hemmerle J.
Published: July 2006

A TEM study was made of the response to synthetic hydroxyapatite prepared in powder form and implanted for 6 and 12 months respectively in infrabony lesions in 2 adult patients with chronic periodontitis and tooth mobility. Round or oval‐shaped crystal aggregates, ranging in diameter from 1 to 20 μm, were surrounded by connective tissue free of inflammatory cells. The aggregates were made up of loosely‐packed individual synthetic hydroxyapatite crystals, with a mean diameter of 128.12±14.57 nm, separated by an amorphous matrix containing few collagen fibrils. In the 6‐month implants small apatite crystals, of a size similar to those found in adjacent alveolar bone and giving similar diffraction patterns, appeared in the center of the aggregates between the relatively large crystals of synthetic hydroxyapatite. These new apatite crystals filled the amorphous matrix progressively from the center to the periphery of the aggregate. The latter was surrounded either by fibroblasts or by osteoblasts and osteoid tissue. In the 12‐month samples a calcified collagenous bone matrix enveloped the crystal aggregates. Typical osteoclasts, lacking a brush border, were evident around certain aggregates. Some osteoclasts contained large vacuoles filled with synthetic hydroxyapatite crystals.
The influence of zinc iontophoresis on in vitro adherence of fibroblasts to periodontally‐diseased cementum
Authors: Kataoka M. , Gado M. H. , Shimomura Y. , Lake F. , Sharawy M. , Gangarosa L. P.
Published: July 2006

This in vitro study examined whether iontophoresis of zinc ions aided adherence of fibroblasts to the root surfaces of periodontally‐diseased teeth. Iontophoresis of zinc ions into extracted, periodontally‐diseased human teeth was performed. Controls consisted of untreated diseased teeth and healthy unerupted teeth. Comparison was also made with teeth that were rinsed in zinc fluoride solution or in 45% phenol. Fibroblasts (L929) adherence was measured by trypan blue staining or by cell counting. The results demonstrate that fibroblasts adhere equally well to: 1) healthy root surfaces, 2) diseased root surfaces treated with 45% phenol, or 3) diseased root surfaces treated by iontophoresis of zinc ions. Cell adherence in these groups was significantly greater than adherence in groups of periodontally‐diseased teeth which were either untreated or rinsed with ZnCl2. Iontophoresis with zinc ions appears to be an effective method of increasing cellular adherence to periodontally‐diseased roots.
Reproducibility of phase‐contrast microscope measurements of percentage motile microorganisms in samples removed from the dorsum of the tongue
Authors: Wolffe G. N. , Van der Velden U.
Published: July 2006

The purpose of this investigation was to determine the accuracy of measurements of percentage motile microorganisms in samples removed from the dorsum of the tongue, using a phase‐contrast microscope. The results indicated that the percentage of motile microorganisms in a bacterial sample can be accurately assessed provided that a short interval of time elapses between sampling and measuring. Furthermore, it appeared that the percentage of motile microorganisms varied during the course of the day.
Immunohistological evidence for gingival lgE‐bearing cells in human periodontitis
Authors: Hara Yoshitaka , Maeda Katsumasa , Akamine Akifumi , Miyatake Sachiko , Aono Masao
Published: July 2006

Specimens of gingiva from 78 lesions taken from 52 patients with chronic periodontitis and gingiva from clinically healthy subjects or subjects with gingivitis were obtained. The patients and control subjects were placed into three groups according to age. The numbers of IgE‐bearing cells and other classes of immun‐oglobulin‐bearing cells were counted, and the ratios of those cells to the total numbers of infiltrating cells were determined. There was a predominance of IgG‐bearing cells, followed by IgA‐bearing cells; the numbers of IgM‐ and IgE‐bearing cells were small. IgE‐bearing cells were observed in gingivaI specimens with a small infiltration. In moderately and severely infiltrated lesions, IgE‐bearing cells were observed most frequently in the specimens, and the ratio of IgE‐bearing cells to total inflammatory cells was significantly elevated. These findings show that local IgE synthesis is highest in the gingiva of young patients with periodontitis and supports the concept that a hypersensitivity reaction mediated by IgE may play a role in periodontitis.
A trypsin‐like protease from Bacteroides gingivalis: partial purification and characterization
Authors: Sorsa Timo , Uitto Veli‐Jukka , Suomalainen Kimmo , Turto Heikki , Lindy Seppo
Published: July 2006

Extracts of cell sonicates of Bacteroides gingivalis were shown to contain proteo‐lytic enzymes capable of degrading connective tissue proteins. In this study, neutral proteolytic enzymes, i.e. collagenase and a trypsin‐like protease, were isolated. The trypsin‐like protease was readily separated from collagenase by affinity chromatography on Benzamidine‐Sepharose. Proteases were further purified by gel filtration on Sephacryl S‐200; apparent molecular weights of 35 kDa and 70 kDa were obtained for a trypsin‐like protease and collagenase, respectively. Further characterization of the potent trypsin‐like protease showed that the enzyme was inhibited by serine protease inhibitors phenylmethylsulfonyl fluoride and benzamidine and by metalloprotease inhibitor EDTA, as well as ascorbic acid. Activation of the enzyme was observed with reducing agents and human serum. The trypsin‐like protease was found to be capable of degrading native type IV collagen and denatured type I collagen but not native type I collagen. Thus, we conclude that in addition to collagenase a potent trypsin‐like protease from Bacteroides gingivalis may be involved in the etiopathogenesis of periodontal disease. Since the trypsin‐like protease is able to degrade the basement membrane collagen (type IV) in the presence of human serum, this enzyme may be a potent virulence factor of Bacteroides gingivalis in relation to invasiveness and connective tissue destruction.
Extraoral control of geometry for digital subtraction radiography
Authors: Jeffcoat M. K. , Reddy M. S. , Webber R. L. , Williams R. C. , Ruttimann U. E.
Published: July 2006

The use of a cephalostat to stabilize projection geometry for subtraction radiography was investigated. Six replicate repositionings of patients within a cephalostat indicated that the mean angular disparity between repositioning was 0.33 ± 0.10 degrees. Subtraction images produced from films of a phantom with artificial periodontal defects exposed using the cephalostat or stent technique were compared. There was no significant difference in the standard deviations of the gray level histograms obtained using the two methods. However, the ability of 10 investigators to detect the presence or absence of simulated periodontal lesions was superior from subtraction radiographs produced from cephalostat‐based images when compared to stent‐based images (p < .02). Sets of radiographs taken of 6 patients on the same day or 3 months apart indicate that the cephalometric technique may be used to stabilize projection geometry.
Vascularly oriented differentiation gradient of osteoblast precursor cells in rat periodontal ligament: Implications for osteoblast histogenesis and periodontal bone loss
Authors: Roberts W. Eugene , Wood H. Bradley , Chambers David W. , Burk Dorothy T.
Published: July 2006

Paravascular distribution of fibroblastlike cells was determined, under conditions of arrested osteogenesis (resorbing or resting bone surface), in periodontal ligament (PDL) of maxillary first molars from 89‐day‐old male rats. As identified by nuclear volume, less differentiated precursor cells (A) and committed osteoprogenitor cells (A') were predominantly localized within 20 μm of the nearest major blood vessel (NMBV). G1 stage preosteoblasts (C cells) and G2 stage preosteoblasts (D cells) tended to be more numerous away from NMBV. Since the osteoblast (Ob) histogenesis sequence is A → A' → C → D → Ob, the present data were consistent with an osteogenic differentiation gradient radiating from blood vessels. It was concluded that preosteoblast formation (A' → C) occurs in a relatively low cell density (4–5 cells/1000 mm2) area ≥20 μm from NMBV. More than 30 μm from the vessel wall, C cells enter DNA synthesis and become D cells, which divide and migrate toward the bone surface, forming 2 osteoblasts each. This is the first integrated description of the cell proliferation differentiation and migration process associated with osteoblast histogenesis.
Ultrastructural localization and passage of cationized‐ferritin and microperoxidase as tracers in the outward flow of rat gingival crevicular fluid
Authors: Tanaka Teruo , Sakano Akira
Published: July 2006

Cationized‐ferritin (CF, high mole wt 800 000) and microperoxidase (MP, low mole wt 1900) were used to trace the outward pathway of rat gingival crevicular fluid. Gingival blood capillaries were often located near the junctional epithelium (JE). Especially, some capillaries at the coronal end of the JE protruded close to the gingival crevice. CF or MP was transuded from the capillaries and penetrated into the JE after passing through the basement lamina densa (BLD) of the external basement lamina. However, the tracer was partially blocked by the BLD. There was almost no difference between the two tracers in their ability to penetrate into the JE. Thus, the penetration of the tracer into the JE seems to be associated with the components of the BLD such as CF‐binding poly‐anionic sites or MP‐preferential affinity sites independently of the molecular weight and molecular size of the tracer. Once the tracer penetrated into the JE, it entered the gingival crevice through the intercellular spaces of the JE and along the internal basement lamina, because the cell junctions of the JE were leaky. In addition, part of the tracer was taken up by the JE. These findings suggest that only the BLD functions as a rough permeability barrier, and that most cell junctions of the JE are relatively permeable. Therefore, even high molecular weight (800 000) substances readily pass from the gingival capillaries to the gingival crevice. On their way to the crevice, exogenous materials in the fluid are phagocytosed by the junctional epithelial cells.
Periodontal bone loss and immune characteristics after adoptive transfer of Actinobacillus‐sensitized T cells to rats
Authors: Yoshie Hlromasa , Taubman Martin A. , Olson Carolyn L. , Ebersole Jeffrey L. , Smith Daniel J.
Published: July 2006

The immune response, gingival inflammation and periodontal bone loss were examined in rats receiving adoptive transfer of Actinobacillus actinomycetemcomitans (Aa)‐sensitized T cells and oral infection with Aa. Thirty‐eight, 30‐day‐old, male Rowett phenotypically normal (rnu/+) heterozygous rats were placed into three groups: 1) Aa‐sensitized T cell transfer group (AaT), 2) sham‐sensitized T cell transfer group (ST) and 3) no transfer control group (C), infected with Aa, and then sacrificed at 120 d of age. Blastogenesis of splenocytes to PHA and Con A was observed in AaT and ST animals that exceeded the values in C animals. Positive antigenic lymphoproliferation and delayed‐type hypersensitivity (foot pad swelling) to Aa were found in AaT group rats, but weak responses were observed in ST and C group rats. Serum IgG, salivary IgA and IgG antibody concentrations to Aa were elevated in AaT and ST groups compared with the control group after infection with Aa. The numbers of gingival T and B lymphocytes in the AaT group were increased in comparison to the other groups. There was also an obvious increase in horizontal bone loss in the AaT group rats. It is suggested that certain subsets of antigen‐specific T cells may augment destructive functions on periodontal tissues.
Suspected periodontopathic bacteria associated with brokenmouth periodontitis in sheep
Authors: Frisken K. W. , Tagg J. R. , Laws A. J. , Orr M. B.
Published: July 2006

Sheep from a broken‐mouth periodontitis‐affected farm were classified into three groups according to degree of severity of periodontal destruction. Subgingival plaque samples were collected from 10 animals in each group, as well as from 10 sheep from a periodontitis‐free farm, and were plated anaerobically onto a variety of selective and non‐selective media. Results show that several different suspected periodontopathic microorganisms commonly associated with human periodontitis are also present in the plaque of sheep. Black‐pigmented Bacteroides were associated with the severely‐affected category but there were no significant differences between less severely‐affected groups and healthy animals. This suggests either that sampling may not have coincided with periods of activity in these sheep or that other bacteria may be involved in the initiation of the disease. Type II Fusobacterium nucleatum was associated with all disease categories when compared to healthy animals.
Interleukin 1 stimulation of plasminogen activator production in cultured gingival fibroblasts
Authors: Mochan Eugene , Armor Lynn , Sporer Ruth
Published: July 2006

Addition of human interleukin‐1 (IL‐1) to normal human gingival fibroblasts in culture stimulated the production of plasminogen activator (PA). This stimulation could be detected as early as 3 hours after addition of IL‐1, was dosedependent and inhibited by antibody directed against IL‐1. Additional observations suggest that IL‐1 increases PA production. These include: (1) an increase in both intra‐ and extracellular PA activity, (2) the dependence of increased PA activity on RNA and protein synthesis and (3) an increase in immunologically detectable PA molecules by immunoperoxidase staining. Since IL‐1 has been reported to be present in human gingival fluid and PA activity has been associated with connective tissue matrix alterations, the results presented here may provide some insight as to how immune events are linked to soft tissue destruction associated with periodontitis.
Gingival tissue‐produced inhibition of platelet aggregation and the loss of inhibition in streptozotocin‐induced diabetic rats
Authors: Kawamura Keiichiroh , Dohi Toshihiro , Tamal Kazuharu , Shirakawa Masaharu , Okamoto Hiroshi , Tsujimoto Akira
Published: July 2006

Addition of medium incubated with normal rat gingival tissue to platelet‐rich plasma inhibited ADP‐induced platelet aggregation. The ability of rat gingiva to produce activity inhibiting platelet aggregation was enhanced by the addition of arachidonic acid. Diabetic rat gingiva failed to inhibit platelet aggregation but did produce the anti‐platelet aggregating activity in the presence of arachidonic acid. Indomethacin blocked the production of anti‐platelet aggregating activity. There was no difference in conversion of [1‐14C]arachidonic acid to prostaglandins by normal and diabetic rat gingiva. These results suggest that an arachidonic acid metabolite released from gingiva during incubation inhibits platelet aggregation, and the synthesis of the metabolite is impaired in diabetic rat gingiva. A decrease in availability of arachidonic acid may be a causal factor of the defect in diabetic rat gingiva.
Progenitor cell kinetics during guided tissue regeneration in experimental periodontal wounds
Authors: Iglhaut J. , Aukhil I. , Simpson D. M. , Johnston M. C. , Koch G.
Published: July 2006

The present investigation compared the premitotic labelling of cells in the bone and periodontal ligament (PDL) compartments apical to a surgically created fenestration wound containing a “periodontal space.” Buccal fenestration wounds (3x3 mm) were made at midroot level in 4 Macaca fascicularis monkeys. The exposed root surfaces were planed and a piece of millipore filter was placed over each fenestration prior to flap replacement. Wounding in the different dentition segments and sacrifice of monkeys were scheduled to provide observation periods of I h I, 2, 3, 7 and 21 d in each monkey. One hour prior to sacrifice, tritiated thymidine (1 μCi/gm body weight) was administered intravenously. Autoradiographs were used to determine the labeling index (L.I.) of fibroblast‐like cells in each of the three following histologic compartments: PDL, alveolar bone adjacent to the apical border of the fenestration, and the wound proper. No significant differences in the L.I. between the bone and PDL tissue compartments were noted for nearly all of the observation periods. L.I. in the PDL peaked at 2 d while the alveolar bone demonstrated two peaks of activity, one at 2 d and the other at 7 d. Labeled cells first appeared at the edge of the wound proper at 3 d. At 7 d, labeled cells were noted throughout the wound compartment indicating continued activity of migrated cells. The 21‐d specimens demonstrated a few labeled cells in the wound compartment and a reduction of mitotic activity in the adjacent PDL and bone compartments to almost normal levels. The results of the present investigation suggest that both the bone and PDL tissue compartments supply cells to a periodontal wound containing a surgically created periodontal space. Moreover, some of the cells which migrate into the potential space formed by the physical barrier continue to prepare for mitosis as they migrate.
Polyclonal induction of IgG antibody forming cells by stimulation with Actinomyces viscosus T14V
Authors: Harada Yasushi , Ito Hiro‐o , Miki Yasuo , Ebisu Shigeyuki , Okada Hiroshi
Published: July 2006

Actinomyces viscosus has been shown to possess the potential for polyclonal B cell activation (PBA), but this activation mechanism is still not well understood. In this report, the T cell and/or macrophage requirement for PBA and the development of IgG producing plasma cells were investigated in the murine system by using an ultrasonicated extract from A. viscosus T14V (Av. sup). The results were as follows: 1. Av.sup activated B cells polyclonally without any participation of T cells and macrophages. 2. Av.sup could induce IgG as well as IgM antibody forming cells (AFC) polyclonally. IgG AFC were induced from surface IgG‐positive (sIgG+) B cells (memory B cells, which had been immunized with antigens), but not from sIgG− B cells. Therefore, circulating memory B cells may be activated by microbial components at periodontally diseased sites and these may contribute to the formation of an IgG‐producing B cell‐rich lesion.
False positive rates in the determination of changes in probing depth‐related periodontal measurements
Authors: Cohen Mark E. , Ralls Stephen A.
Published: July 2006

False positive rates associated with changes in periodontal probing measurements (changes which are of such magnitude as to be construed as due to disease or healing when the observed changes are actually due to measurement error) were estimated by computerized simulation. In the first phase of the simulation study, various distributions of error variances among sites were evaluated for their ability to produce matches to an empirical distribution of differences between replicate measurements. In the second phase of the study, distributions of variances identified in Phase I were used to estimate the false positive rate, under conditions of no actual change, for detection methods based on critical differences between averaged pairs of measurements. This rate was found to be substantially greater than that predicted using normal distribution probabilities and, for a difference of ≥2.5 mm, approached one false detection per examination of 168 sites. In the third phase of the study, simulation procedures were extended to the tolerance detection methodology and the false positive rate, in the absence of real change, was almost one detection per two examinations. This simulation suggested that perhaps one third of tolerance detected “bursts” of periodontal attachment change may be false positives attributable to measurement error.