Periodontitis is the chronic inflammation caused by bacteria in dental plaque. The interaction between immunocompetent cells, such as T cells and fibroblasts may be involved in the pathogenesis. Integrins and chemokines play important roles in cell adhesion, transmigration and proliferation at such sites of the inflammation. We examined the effects of chemokines, such as MCP-1, RANTES and fractalkine, on binding of PHA-activated T cells to immobilized ICAM-1 and extracellular matrix proteins (ECMs), such as fibronectin, laminin and collagen with a novel adhesion assay system using BrdU. PHA-activated T cells adhered to ICAM-1 and ECMs in a dose-dependent manner and PMA markedly enhanced the adhesion of PHA-activated T cells to ICAM and ECMs. The CC-chemokines, such as MCP-1 and RANTES, enhanced adhesion of PHA-activated T cells to ICAM-1, but not to ECMs, whereas, the CX3C-chemokine, fractalkine had no effect on PHA-activated T cell adhesion. To examine the natural setting of the interaction between T cells and fibroblasts, the binding of PHA-activated T cells to immobilized fibroblast like cell line, E 11 cells was examined. We found that adhesion of PHA-activated T cells to E 11 cells was ICAM-1-dependent and that MCP-1 and RANTES, but not fractalkine, enhanced binding of PHA-activated T cells to E 11 cells. These results suggest that some chemokines have important roles in adhesion of T cells to fibroblasts, which may be involved in pathogenesis of periodontitis through enhancing immunologic reaction at the inflammatory sites. J. Jpn. Soc. Periodontol., 41: 77-86, 1999.
Gingival epithelium provides the mechanical and biologica protective integument of the periodontium. Interleukin-1 (IL-1) is known to play an important role in the progression of periodontal inflammation, and IL-1 receptor antagonist (IL-1 ra) is identified as a specific inhibitor of IL-1. To clarify the expression of IL-1 and IL-1 ra in human gingival keratinocytes, we studied the protein production and mRNA expression of IL-1 a and IL-1 ra in human cultured gingival keratinocytes using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Furthermore, we studied im-munohistochemically the presence of IL-1 a and IL-1 ra in the epithelium of healthy and inflamed gingiva. Results showed that IL-1 a was detected more than IL-1 β in cell lysates and conditioned medium. The level of cell-associated IL-1 a was significantly increased under stimulation of tumor necrosis factor-a (TNF-a), while the level of IL-1 a in conditioned medium and the levels of IL-1 β or IL-1 ra protein were not influenced by TNF-a. IL-1 a and intracellular IL-1 ra mRNA transcripts were enhanced under stimula-tion with TNF-a by RT-PCR. Furthermore, the presence of IL-1 ra, but not IL-1 a, was found by immuno-histochemistry in the epithelium of gingiva. These results indicatethat human gingival keratinocytes express IL-1 a and IL-1 ra, and may be involved in the regulation of inflammation of periodontal diseases by IL-1 a and IL-1 ra. J. Jpn. Soc. Periodontol., 41: 87-98, 1999.
This study investigated the effects of bisphosphonates on the polymorphonuclear leukocyte (PMN) -derived matrix metalloproteinases (MMPs) /MMP-8 and MMP-9 activity in vitro. PMNs extracts were treated with various concentrations (1× 10-6-1× 10-3M) of tiludronate, etidronate, and tetracycline. MMP-8 and MMP-9 activities were assayed using FITC-conjugated type I collagen and type IV collagen as substrate. MMP-8 activity was inhibited by 1× 10-6 M tiludronate and by 1× 10-3 M tetracycline, but not inhibited by etidronate. MMP-9 activity was inhibited by tiludronate, etidronate, and tetracycline in a dose-dependent manner. The results revealed that PMN-derived MMP activities were inhibited by bisphos-phonates. Especially, the inhibition of MMP activities by tiludronate was more evident than that by tetracycline, as is already well-known. In addition to a well-known pharmacological action, inhibition of osteoclastic bone resorption, the capability of bisphosphonates to inhibit the activities of PMN-derived MMPs may be beneficial to prevent tissue destruction in periodontal inflammation. J. Jpn. Soc. Peri-odontol., 41: 99-107, 1999.
The goal of current periodontal therapy is to provide connective tissue adhesion on root surfaces that have lost attachment for which the adhesive capacity of periodontal ligament fibroblasts on the root surface is considered important. In this study, we investigated the effects of changes in the environments surrounding the cells, including properties of the root surface or matrix, on the mode of adhesion of periodontal ligament fibroblasts and on the expression of integrins, with the aim of identifying the mechanism of cell adhesion in the process of wound healing in periodontal treatment. Human periodontal ligament fibroblasts (HPLF) were cultured onto collagen-coated glass plates, which imitated the root surface after root treatment. We then examined by immunohistochemistry the effects of the presence or absence of the ligand-binding site (RGD sequence) of fibronectin recognized by integrins on cellular adhesion, as well as the expression of fibronectin, and integrin β1 and α2 subunits (integrin β1 andα2, respectively), using a confocal laser scanning microscope. The results showed that fibronectin was expressed on cell surfaces, and integrin β1 was mainly involved in cell adhesion in the RGDS (-) medium. On the other hand, although fibronectin and integrin β1 were expressed on cell surfaces in the RGDS (+) medium, they were minimally involved in cell-substrate adhesion and compensatory expression of integrinα2, a collagen receptor, was seen. These findings suggested that characteristics of the root surface and/or the conditions surrounding cells have to be considered in order to be certain of obtaining HPLF attachment during periodontal regeneration. J. Jpn. Soc. Periodontol., 41: 108-117, 1999.
The gingiva is mucosal tissue composed of gingival epithelium and gingivallamina propria. The present study examined the distribution and ratio of oxytalan fibers of gingival lamina propria related to aging and types of the diet in guinea pig. A group of 8 guinea pigs was weaned at 8 weeks of age (Young group) and another group of 8 guinea pigs was weaned at 60 weeks of age (Old group). Each group was divided into two groups ; they were fed 8 weeks with either soft diet or hard diet. The frontal sections of the mandibular incisor region were prepared and stained with H. E. stain, Masson's trichrome stain and the Weigert's resorcin fuchsin preoxidation method ; preoxidation was performed in a solution containing 0.3% H2SO4 and 0.3% KMnO4 for 30 min. Oxytalan fibers in the gingival lamina propria were determined quantitatively with the computer-assisted image analyzer system. The results showed pathological changes of collagen fibers in old animals exposed to the soft diet. Concerning the ratio of oxytalan fibers, a prominent increment was particularly observed in the old groups. On the other hand, no significant differences were found in young groups fed with different diets. This study indicated a tissue repair mechanism by compensation of oxytalan fibers for collagen fiber loss in gingival lamina propria of old group fed with soft diet. J. Jpn. Soc. Periodontol., 41 : 118-124, 1999.
The purpose of this study is to evaluate the effects of Guided Tissue Regeneration (GTR) with biodegradable collagen membrane (Tissue Guide™) and natural apatite composition materials (Bone Ject®) for experimental periodontal bone defect. The mesial roots of the lower third and fourth premolars from 10 beagle dogs were used. Mucoperiosteal flaps were reflected and bone defects measuring 5mm in width and 5mm in height were created. The experimental bone defects were treated by four different methods : (1) flap operation (control), (2) GTR with biodegradable collagen membrane (T group), (3) grafting Bone Ject® (B group), (4C) I GTR with Tissue Guide™ and grafting Bone Ject® (TB group). After 24 and 48 weeks of healing, histologic sections were processed and histologically observed, showing that the TB group produced more new bone and new cementum than the other groups. When granules of Bone Ject® remained, the structure was observed smaller. Our study suggested that Bone Ject® reconstract a periodontal tissue while it is absorbed partially. J. Jpn. Soc. Periodontol., 41: 125-143, 1999.
In epidemiology and clinical research, the reproducibility of clinical parameters is most important. In this study, we examined the inter-and intra-examiner reliability of each of the following clinical parame -ters: plaque index (PH), gingival index (GI), probing depth (PD), attachment level (AL), and bleeding on probing (BOP). PD, AL, and BOP measurements were carried out with an electronic probe, The Florida Probe®. The measurements were performed on 17 subjects (5 patients and 12 healthy subjects). Clinical parameters were measured twice in each subject at intervals of 1-2 hours. For inter-examiner reliability, the first measurement was performed by one examiner and the second measurement by another examiner. For intra-examiner reliability, each measurement was performed on all subjects by one examiner. Interexaminer reliability of clinical parameters were 0.52 (PH), 0.52 (GI), 0.59 (BOP) (P1I, GI, BOP: Kraemer's Kappa), 0.73 (PD), 0.56 (AL) (PD, AL: correlation coefficient). Intra-examiner reliability of clinical parameters were 0.71 (PH), 0.66 (GI), 0.52 (BOP) (PH, GI, BOP: Kraemer's Kappa), 0.97 (PD), 0.94 (AL) (PD, AL: correlation coefficient). The results indicate that clinical parameters (PH, GI, PD, AL, BOP) can demonstrate good inter-and intra-examiner reliability. J. Jpn. Soc. Periodontol., 41: 144-152, 1999.
The purpose of this study was to assess the clinical efficacy of the periodontal surgery with porous bone graft material (Bio-Oss®: BiO) and collagen membrane (Bio-Gide®: BiG). Sixtyseven adult periodontitis patients each having a Class II furcation defects or vertical defects, participated in the study. Mucoperiosteal flaps were elevated and granulation tissue in the defects were debrided with hand instruments. After each defect was filled with BiO, BiG was positioned over graft material and the defects. The flaps were replaced coronary to cover the membrane ensuring primary closure. The clinical examination were taken before surgery, at 1, 3 weeks, 3 and 6 months after surgery. Postoperatively, clinical healing generally progressed uneventfully in all patients. The significant differences were found in probing depth and clinical attachmentlevel between pre-surgery and 6 months postsurgery measurements. Mean probing depth was reduced from 6.74±1.17mm to 3.08±1.17mm with a mean reduction of 3.67±1.21mm. Mean clinical attachment level was reduced from8.39±1.99mm to 5.60±2.11mm with a mean clinical attachment gain of 2.79±1.38mm. The improvement of radioluency at defect area was noted in 48 of 66 patients. The side effects was not observed in any cases. This study revealed that the periodontal surgery with BiO and BiG is safety and clinical usefulness. J. Jpn. Soc. Periodontol., 41 : 153-165, 1999.
The aim of the present study was to analyze the recognition of gingival redness using computer-assisted colorimetric image analysis. Nine dentists, who had career as a clinical periodontist for over 10 years, participated in the evaluation of gingiva. Dentists were shown 4 digital gingival images on the monitor, then defined the regions (ROI) from the point of color according to the category. The images used in this study were saved with Tag Image File Format (TIFF), those had 224 color depth (red 28, green 28, blue 28). The size of each image was 2, 268×1, 764 in pixel-number and 11MB in memory size. The category consisted of healthy, slightly inflamed and severely inflamed. The number of pixels and the average trichromatic gray value of the ROI were measured. Statistical significance among 3 groups was analyzed with Student's t-test. Then 1 image of the inflamed gingiva was separated into 3 trichromatic images. The contrast similarity of the trichromatic images to the original color image was investigated. The most available value in trichromatic color for the recognition of gingival redness was that of green (t-value between healthy and slightly inflamed: R; 3.12 (p=2.3×10-4) G; 4.16 (p=6.5×10-5) B; 3.29 (p=1.4× 0-4), t-value between slightly inflamed and severely inflamed: R; 4.45 (p=2×10-5) G; 9.18 (p=-1× 10-9) B; 9.45 (p=-1×10-9)). Of the 3 separated trichromatic images, the most similar image to the original was the green image. These findings suggest that the green value is important in recognizing the redness of gingiva by dentists. We are going to utilize a modified green value in the development of an algorithm that recognizes the redness of gingiva automatically. J. Jpn. Soc. Periodontol., 41: 166-172, 1999.
Root surface can be exposed to the oral environment by periodontal disease and its treatment, and might therefore be at risk for caries attack. Stannous fluoride has been demonstrated to have a preventive effect on root caries. We prepared an 8% stannous fluoride gel that was convenient for topical application. The purpose of this research was to study the inhibition of dentin demineralization by 8% stannous fluoride gel. Five kinds of treatments were each done for 4 minutes as follows: A: apply 8% stannous fluoride gel (Gel), B: immerse in 8% stannous fluoride solution (SnF2), C: apply acidulated phosphate-fluoride gel (APF), D: apply 3% propylene glycol alginate solution (PGA) and E: immerse in deionized water (control). After treatment, each specimen was immersed in 0.2 M acetic acid for 30 minutes for dentin demineralization. The concentrations of calcium (Ca) in 0.2M acetic acid were determined and each specimen was observed by scanning electron microscopy (SEM). The concentrations of Ca in 0.2M acetic acid after treatments A, B, and C were significantly lower than those after treatments D and E (p<0.001). With SEM observations, dentin surfaces after treatments D and E showed a lack of smear layer and abundances of patent dentinal tubuli. The numbers of patent dentinal tubuli on dentin surfaces after treatments A, B and C were fewer than those after treatments D and E. It is therefore concluded that our gel may have a preventive effect on root caries. J. Jpn. Soc. Periodontol., 41: 173-179, 1999
The exposure of root surfaces during periodontal treatment often results in dentin hypersensitivity. Although there are various treatments for this hypersensitivity, they are not always effective in all cases. The purpose of this study was to evaluate the pain relief effect of pulsed Nd: YAG laser irradiation for dentin hypersensitivity during periodontal treatment. One hundred teeth of 45 patients (20 male, 25 female, aged 24 to 62 years) were examined in this study. Conditions for irradiation were carried out at the laser energy 1.5 W, pulses per second 15 pps, irradiation time 60 sec. And Nd: YAG laser irradiated on mucogingival surfaces stained with Chinese ink. The degree of dentin hypersensitivity to air blast and tooth brushing were evaluated before and after Nd: YAG laser irradiation using visual analogue scale (VAS), which is considered a practical and valid method for assessing the efficacy of treatments for dentin hypesensitivity. Also, we observed mucogingival surfaces before and after Nd: YAG laser irradiation by oral photograph and laser microscopy. Nd: YAG laser irradiation was effective for dentin hypersensitivity with gingival recession within 3mm. There was a statistially significant difference in the pain relief effect between anterior and posterior teeth (p<0.001), and no damage was found on mucogingival surfaces after Nd: YAG laser irradiation. This study suggested that Nd: YAG laser irradiation may be useful for dentin hypersensitivity during periodontal treatment. J. Jpn. Soc. Periodontol., 41: 180-487, 1999.
Development of diagnostic tests based on gingival crevicular fluid (GCF) composition requires an understanding of sampling variables. Sample time and sample sequence number are of great importance, but currently no consensus exists, especially on repeat sampling. The aim of this study was to discover whether a first or a subsequent sample is better for determining sulfated glycosaminoglycan content in GCF. Two 30-second samples of GCF were collected on paper strips from 192 teeth with healthy, gingivitis, and adult periodontitis. After sampling, the strips were stained with 0.2% alcian blue solution containing 0.05 M MgCl2, 0.4M guanidine-HCl, 0.02M sulfuric acid, and 0.25% Triton X-100 at pH1.5, and analysed in a chromatoscanner. Results showed a higher level of sulfated glycosaminoglycan in first samples than in second samples at 81 sites (47.9%), and conversely, a higher level of sulfated glycosaminoglycan in second samples than in first samples at 37 sites (21.9%). The percentage of sites with second samples richer than first samples rose with increasing gingival index score and probing pocket depth. An in vitro study showed that the fluid existed in too much volume, so that the paper strips were unable to absorb all of it. This study shows that use of first samples may be better than second samples for measurement of sulfated glycosaminoglycans in GCF. J. Jpn. Soc. Periodontol., 41: 188-194, 1999.
The purpose of this study was to assess the usefulness of a portable sulfide monitor (Halimeter®Model RH 17 E, Interscan, U.S.A.), and to examine the relationship with oral malodor and periodontal indices. One hundred and one healthy adults, students and staff of The Nippon Dental University School of Dentistry at Niigata, were measured for oral malodor using a portable sulfide monitor and organoleptic examination. After that, thirteen individuals were examined, for whom periodontal indices (probing depth (PD), plaque control record (PCR), plaque index (PlI), and bleeding on probing (BOP)) were compared with oral malodor. The result showed that the organoleptic scores overlapped with volatile sulfur compound values. However, the organoleptic scores were correlated with volatile sulfur compound values. These results suggest that this portable sulfide monitor may be useful as a chair-side measurement of oral malodor. However, no correlation was found between volatile sulfur compound values and periodontal indices. J. Jpn. Soc. Periodontol., 41: 195-200, 1999.
Antibiotic treatments for clinical periodontal fields have been in need of rapid antibiotic susceptibility test. However, it takes long time and high cost to perform drug susceptibility tests for pathogenic bacteria from clinical samples. In this report, we have examined the applicability of a totaly new oxygen electrode system for rapid drug susceptibility test (DOX-10) to a periodontal bacterium, which measures dissolved oxygen content in culture media. This system stands on the hypothesis that oxgen consumption will decrease if the bacteria is susceptible to an antibiotic. A facultative anaerobic bacterium, Actinobacillus actinomycetemcomitans-Y 4 (ATCC 43718 serotype b; A. a.) was aerobically used in the experiment at a concentration of 1×108 cells/m/ for each channels. The dissolved oxygen content in a channel gradually decreased for 1 hour measurement. Antibiotics effective to A. a., tetracycline and minomycine, reduced the decrease of the dissolved oxygen content in a channel indicating that oxygen consumption by the bacteria was diminished, but the other antibiotics ineffective to A. a., bacitracin and vancomycin, did not. These results indicate that this system has a high feasibility for the application of drug treatment in periodontal fields. J. Jpn. Soc. Periodontol., 41: 201-209, 1999.