Priodontal diseases are known to progress as chronic inflammations but it has been shown that an acute phase occasionally occurs. There have been a few microbiological investigations of this acute phase. This study was designed to characterize subgingival flora in the acute phase of adult periodontitis using an immunofluorescence technique and bacterial culture method.
Subgingival plaque samples were obtained from 1) 12 periodontally healthy subjects, 2) 13 adult periodontitis patients, and 3) acute sites in 31 patients with adult periodontitis. As criteria for the acute phase, patients who had at least two clinical symptoms of pain, swelling, redness, or a feeling of warmth in periodontal pockets were selected. In some acute phase studies, samples were taken from control sites of matched pocket depth. For the indirect immunofluorescence technique, species-specific rabbit antibodies against 4 Periodontopathic bacteria, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Campylobacter rectus, were used for the investigations of subgingival plaque. In some cases, a bacterial culture method was also employed. For treatment of the acute phase of adult periodontitis, slow release Minocycline (Periocline ®) w as administered locally. Changes in the clinical parameters and microflora were investigated before and one week after the application of Minocycline.
Neither A. actinomycetemcomitans, P. gingivalis, nor C. rectus could be detected in the healthy subjects. In adult periodontitis patients, the total number of bacteria and the proportions of P. gingivalis, P. intermedia and C. rectus correlated significantly with pocket depth. In the acute phase, the total number of bacteria as well as the percentage of P. gingivalis and C. rectus in the acute site showed a tendency to be increased, as compared to those in the control site. A. actinomycetemcomitans and P. intermedia showed no such tendency. Administration of slow release Minocycline in the acute phase led to clinical improvement in most cases, and the percentages of P. gingivalis and C. rectus were significantly reduced.
The results indicate that elevations in the proportions of P. gingivalis and C. rectus might participate in development of the acute phase.

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The purpose of this study was to examine the characteristics of the periodontal ligament in class III furcation defects treated with guided tissue regeneration (GTR). Through-and-through furaction defects, 3 mm in vertical dimension, were experimentally created in dogs. Examined teeth were treated according to the GTR principle, while control teeth were treated without membrane application. All teeth were subjected to histopathological examination and histometrical measurements. The results of the histopathological examination revealed that the control teeth showed furcation defects with a continuous epithelial lining and bone formation was minimal. The examined teeth showed that furcation defects healed by complete closure with connective tissue and had a continuous epithelial lining. The root surface of the furcation was covered with new cementum and bone regeneration occurred in areas adjacent to the root surface to which periodontal fibers were attached. Histometrical measurements revealed that there was a positive correlation between newly formed tissue and tissue remaining in the furcation. The results suggest that: (1) new cementum and new bone tissue are observed with blood vessels from periodontal ligament tissues, (2) regenerated tissues which were considered to have been derived from periodontal ligament are inhibited -by gingival connective tissues, (3) an important factor in the complete closure of a furcation was the ratio of the basal width of the defect to the height of the furcation.

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This study evaluated whether periodontal regeneration following reconstructive surgery using Lactide/Glycolide copolymer-atelocollagen complex membrane (LGA) hybridized in vivo may be enhanced or not. Circumferential bone defect models which were produced surgically around mesial roots of the third and fourth premolars in twelve mongrel dogs were used. Three modalities were studied: 1) Control group, in which no membrane was used, 2) LGA group, in which the internal surface of the flap was lined with LGA membrane and 3) HLGA group, in which the internal surface of the flap was lined with LGA membrane hybridized in vivo. After four and twelve weeks of wound healing, the dogs were sacrificed and healing response was analyzed histometrically. The membrane was clearly demonstrated the new cementum formation and the new bone formation were significantly increased in the HLGA group. This result supports that Guided Tissue Regeneration technique using HLGA membrane was one of the methods to promote periodontal tissue regeneration more positively.

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The purpose of this study was to evaluate the ffect of using recombinant human BMP-2 (rhBMP -2) combined with a fibrous collagen membrane FCM) for periodontal therapy in adult rats.
We originally developed FCM as a biodegradable barrier membrane for guided tissue regeneration techniques. It was made from telopeptide-depleted bovine skin collagen. In this study, we have made improvements for better manipulation, and used a new collagen membrane (FCM 3) as the carrier of rhBMP-2. The rhBMP-2 (0.5, 1.0, 2.0. μg), provided by Yamanouchi Pharmaceutical Co. Ltd., was precipitated onto approximately (0.5 mm.-4.0 mm mean weight 150 μg) of FCM 3, and the complex was then lyophilized and stored at . -70...
The complex was implanted in dorsal subcutaneous and palateal subperiosteal sites of 20 adult Wistar rats (male, 12 weeks old). Newly formed bone was examined histologically after 21 days and 42 days of implantation. Some groups were assigned to the time course study, and bone formation was examined by a hard tissue labeling technique.
The results showed that no ectopic bone formation had occurred in dorsal sites by the 21 st postoperative day. On the other hand, in palatal sites, new bone was observed around the carriers in 1.0μg and 2.0 . μg rhBMP-2 combined-groups. In t. hEe 2.0 . μg group, newly formed bone, that was connected with original palatal bone, covered the carrier, and the collagen fiber and bone matrix fiber were directly linked. Furthermore, the new bone was thick and the remaining carrier was fused with palatal bone on the 42 nd postoperative day. There were minimal inflammatory cells around the complex. No cartilage was found in any specimens.
Using a hard tissue labeling technique, it was found that new bone formation promoted by rhBMP -2 may occur around the carrier as early as the 7 th postoperative day. On the 21 st day, new bone was seen not only on the surface but also in the carrier body.
The results indicate that rhBMP-2 combined with a new collagen membrane (FCM 3) has good potential for application to periodontal regenerative therapy.

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We examined the suppressive effect of human gingival fibroblast culture supernatant (FB sup) on the interleukin-2 receptor (CD 25: IL-2 R) expression on anti-CD 3-stimulated T-cells obtained both from peripheral blood (PB) and gingival tissues. The cells were incubated for 24 hours in the presence of FB sup in anti-CD 3-coated culture well plates in 5% CO₂ in air at 37.., washed and prepared for two-color flow cytometry. Staining of PB -T-cells from healthy donors with FITC-labelled anti-IL-2 R combined with PE-labelled anti-CD 4, CD 8, or CD 45 RO showed that IL-1-stimulated FB sup suppressed T-cell activation. Within the IL -1-stimulated FB sup-incubated T-cells, the sup -pressive effect was significantly stronger on CD 8+ T cells and CD 45 RO+ T cells than on CD 4+ T cells and CD 45 RO-T cells, respectively. The same tendency was found within prostaglandin E₂ PGE 2) -incubated T-cells. However, FB sup (containing both IL-1 and indomethacin did not exert this suppressive effect on T-cell activation data not shown). We then assessed the difference of responsiveness to anti-CD 3, IL-1-stimulated FB sup, or PGE 2 between T-cells from periodontitis -affected gingiva and those from autologous PB . The activation of gingival CD 45 RO T cells was also suppressed by IL-1-stimulated FB sup or PGE 2. However, gingival CD 45 RO + T cells displayed decreased responsiveness to anti-CD 3, IL -1-stimulated FB sup, or PGE 2. In conclusion, the findings suggest that IL-1-stimulated gingival fibroblast suppressed anti-CD 3-induced T cell activation by producing arachidonic acid metabolite via the cyclooxygenase pathway. However, the sensitivity of gingival CD 45 RO + T cells to IL -1-stimulated FB sup was less than that of autologous PB-CD 45 RO+T cells.

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This study was disigned to investigate the relationship between the subgingival microfloral shift and the progression of clinical observations in ligature and occlusal trauma-induced monkey periodontitis at 16 weeks. Subginigval specimens were obtained by paper point-sampling, and were evaluated for the total number of bacteria using bright light phase contrast microscopy and for the each number and ratio to total bacteria number of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans using indirect immunofluorescence. Clinical examination and microbial evaluation were performed on mesial, distal, buccal, and lingual (palatal) sites of posterior teeth. Experimental sites were divided into three groups. Group 1, non-ligated sites (n=24), exhibited chronic generalized gingivitis and a slight increase in the total number of bacteria, but no change in the counts and ratio of each of the above bacteria. Group 2, ligated sites (n=36), revealed increased both clinical attachment loss and radiographic evidence of alveolar bone loss. The subgingival flora showed a significant increase in the total number, in each bacterial number and in their ratios. Group 3, sites with the combination of ligature and trauma from occlusion of the jiggling type (n=36), revealed a greater degree of attachme nt loss and bone loss than group 2. No significant microbial changes were noted between the two groups.
The clinical pattern of attachment loss was associated with the total number of bacteria and the counts and rates of P. gingivalis, P. intermedia, and A. actinomycetemcomitans. While trauma from occlusion accelerated the progression of periodontitis, no significant microfloral shift was observed.

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Our previous reports have clearly demonstrated that curettage of superficial cementum in periodontally involved teeth during flap surgery can provide a suitable root surface for gingival tissue attachment. However, the results also showed that some deep lacunae occasionally remained even after surface-cementum-curettage. The present study was designed to evaluate the distribution, area and depth of resorption lacunae in periodontally involved human teeth under various canal conditions (1. vital teeth; 2. obturated teeth; 3. discolored obturated teeth; 4. teeth with infected root canals 5. discolored teeth with infected root canals) in order to examine whether superficial cemental curettage is applicable to such teeth. There was no significant difference (p<0.05) in the distribution of resorption lacunae among any of the groups. The depth of resorption lacunae in each group ranged from 15.2. μm (vital teeth) to 61.42, μm (colored teeth with infected root canals). The depth of resorption in other groups, except colored teeth with infected root canals, was less than 40. μm. The results suggest that the curetting -surface-cementum procedure exposes healthy cementum leaving no resorption lacunae in most periodontally involved teeth.

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The present study was performed to investigate the effect of transforming growth factor-ß (TGF -ß) and lipopolysaccharide (LPS) on cell growth, colony formation and collagen synthesis of human periodontal ligament fibroblasts (HPLF) and human gingival fibroblasts (HGF). LPS was extracted from P. gingivalis, P. interrnedia and E. coli. We tested the effect of TGF-ß and/or LPS on HPLF cell and HGF cell proliferation in 0.3% soft agar cultures in conjunction with EGF for 14 days. Plates were scored by counting the number of colonies in a 1 cm² field. Cells were plated at confluence in 6-well multi-dishes, and culture media were replaced with serum free medium containing ¹⁴C -proline and TGF-ß and/or LPS . Following this procedure, the culture medium and extracellular matrix were separately collected to determine ¹⁴C -proline incorporation . The radio-labeled proteins were analyzed by SDS-Polyacrylamide Gel Electrophoresis and visualized fluorographically. Colony formation and collagen synthesis in HPLF cells and HGF cells were stimulated by TGF-ß, but not LPS. While cell growth was not influenced by TGF-fi and LPS at same concentration. However, LPS did inhibit the colony formation and collagen synthesis stimulated by TGF-ß.

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Lipopolysaccharides (LPS) extracted from oral black-pigmented anaerobic rods with hot phenolwater have been reported to exert bioactivities different from those of classical endotoxin. This study was carried out to isolate a novel immunomodulator different from endotoxin from the phenol-water extract of Prevotella intermedia ATCC 25611. The bacterial cells were extracted twice with phenol-water at 67.. for 20 min. The pooled extract in the water phase was dialyzed against distilled water, and ultracentrifuged at 100, 000 x g for 3 hr to remove the lipopolysaccharide (LPS). The resultant supernatant was lyophilized and after being resolved in 0.2% sodium deoxycholate, it was subjected to Sephadex G-100 column chromatography with monitoring of mitogenicity on the splenocytes from C3H/HeN and C3H/HeJ mice, Limulus activity, and then deoxycholate polyacrylamide gel electrophoresis (DOCPAGE), to separate the target material and residual LPS. The first fraction showed mitogenicity on the splenocytes from both strains of mice, only slight Limulus activity, and high-molecular-weight bands, 10-12 K, on DOC-PAGE. The latter fraction showed mitogenicity on the splenocytes from the C3H/HeN but not the C3H/HeJ mice, strong Limulus activity, and a single low-molecularweight band, approximately 3 K, on DOC-PAGE. These properties of the latter fraction were in accordance with those of the LPS (LPS-PCP) extracted from the P. intermedia with the phenol -chloroform-petroleum ether mixture . The former fraction was treated with NP 1 nuclease, and rechromatographed on Sephadex G-100. The resultant Prevotella mitogen (PM) fraction exhibited activities similar to those of the parent fraction, and also stimulated peritoneal macrophages from both the C3H/HeN and C3H/HeJ mice to produce interleukin (IL) -6 and tumor necrosis factor (TNF) -a. The mitogenicity of the PM fraction was resistant to heat (100.. for 1 hr) and protease-treatments. Furthermore, the PM fraction stimulated human peripheral blood cells and gingival fibroblasts to produce IL-6. The activities of the PM on the splenocytes and macrophages from the C3H/HeN mice were scarcely inhibited by polymyxin B. By contrast, the LPS-PCP lacked activity on the cells from C3H/HeJ mice or human gingival fibroblasts and its activities on the cells of C3H/HeN mice were completely inhibited by polymyxin B. The LPS (LPS-PW) extracted from the bacteria with hot phenol-water exhibited both the properties of the PM fraction and LPS-PCP. These findings suggest that the unique bioactivities of the LPS LPS-PW) of the bacteria, which differed from those of the classical endotoxin, were derived from the PM fraction, but not from the LPS itself.

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The purpose of this study was to investigate the phenotypic characteristics and coaggregation properties of Actinomyces odontolyticus strains isolated from periodontal pockets of adult periodontitis patients. Wild strains of A. odontolyticus were isolated and identified by their morphological and biochemical features. Their prevalence was 52.5%, and accounted for up to 9.3% of cultivable microbiota. A. odontolyticus seemed to comprise a larger component of the subgingival microflora in 3 to 5 mm deep pockets than in deeper ones. Seven of the twenty-one strains formed large colonies over 2 to 3 mm in diameter on blood agar plates. As for biochemical tests, 90.5% of isolates hydrolyzed esculin, 61.9% starch, and 85.7% produced acid from xylose. These are relatively high positive percentages, especially esculin hydrolysis, compared with other reports dealing with strains isolated from other than periodontal pockets or type strains.
Coaggregation properties of A. odontolyticus with Porphyromonas gingivalis were also investigated. It was not inhibited by lactose. Coaggregation molecule (s) on A. odontolyticus resisted heat, trypsin, pronase E and periodate. On the other hand, complementary molecule (s) on P. gingivalis resisted trypsin and pronase E but showed heat and periodate lability. N-acetylneuraminic acid (NANA) completely inhibited the coaggregation, as did treatment of P. gingivalis cells with neuraminidase. Cysteine, arginine, and glutamic acid were also effective inhibitors. It was suggested that coaggregation molecule (s) on A. odontolyticus recognize the NANA residue on P. gingivalis. Cysteine, arginine, and glutamic acid might be implicated in the epitopes of coaggregation molecule (s). Bacterial cell hydrophobicity influenced coaggregation.

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Bone morphogenetic protein (BMP) is thought to require a carrier for bone induction. Our previous study demonstrated that fibrous collagen membrane (FCM) is effective as a carrier of BMP partially purified from bovine bone. As handling of FCM was difficult under wet conditions, FCM No. 3 (FCM 3) was newly developed. The fibers of FCM 3 were thickened by additional alkaline dialysis. The purposes of this study were to examine the efficacy of FCM 3 as a carrier of partially purified BMP and the capability of BMP-combined FCM 3 to regenerate periodontal tissue.
Firstly, in order to examine the efficacy of FCM 3 as a carrier of BMP, BMP-combined FCM 3 s were implanted into dorsal subcutaneous sites and palatal subperiosteal sites of two 12-week-old (adult) rats. Histological specimens were obtained 3 weeks after implantation. In the dorsal group, ectopic bone formation was observed, but not cartilage. In the palatal group, formed bone was continuous with host bone, but no cartilage was observed.
Secondly, the capability of BMP-combined FCM 3 to regenerate periodontal tissue was evaluated. Bilateral bone defects were made surgically in the palatal alveolar bones of the maxilla in 28 adult rats. BMP-free FCM 3 s (group C) or BMP-com-bined FCM 3 s (group E) were implanted into the bone defects. Nothing was implanted in the control group (group N). Histological specimens were obtained 1, 2, 3 and 6 weeks after implantation. In group N, osteoblasts did not appear in the defect wall till the first week. In group C, the implants remained and no osteoblasts were seen in the defect wall until the third week. In group E, the implants remained until the third week, in the first week osteoblast-like cells accumulated between the implant and the defect wall, in the third week new bone surrounding the implant was observed, and in the sixth week the line of demarcation between the new bone and host bone was difficult to distinguish and the height and width of the alveolar bone appeared to be much greater than those of other groups.

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The present study was performed to apply artificial dermis, and to investigate the epithelial regenerative response of defects in the rat palatal gingiva after implantation of a collagen marix (a composite material of fibrillar atelocollagen and heat denatured atelocollagen). The epithelial regeneration process was observed using immunostaining with 5-bromo-2'-deoxyuridine (BrdU). A collagen matrix was implanted into the defects in the experimental group. The defects in the control group received no implants.
The BrdU labeling cell index in both groups was examined, using statistical methods, at 1, 3, 5, 7 and 14 days after the implantation. The following results were obtained. The BrdU labeling cell index was 28.7% in the control group and 16.6% in the experimental group at 1 day after the implantation. The rate of the control group was higher than that of the experimental group, but this difference was not significant. At 3, 5, 7 and 14 days, there were no differences in the BrdU labeling cell index between the experimental and control groups. The above results suggest that this collagen matrix is not an obstructive factor in the wound area, and that this material promotes epithelial regeneration during the process of connective tissue regeneration and the resorption of the collagen matrix.
Requests for original article repr i (nts should be addressed to Dr. KODAMA)

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We have investigated the effects of periodontal ligament cells on osteocalstic bone resporption activity in cases of tooth replantation.
Human periodontal ligament Cells (Pla) were isolated from impacted wisdom teeth and proliferated in culture dishes. Pla was seeded on bovine bone slices for 24 h in a-MEM supplemented with 10% FCS. Isolated rabbit osteoclasts were added to Pla coated bone slices and cultured another 48 h under the same conditions. Bone slices were swiped, to remove cells, and stained immunochemically using anti-collagen type I antibody to visualize the resorption lacunae. The number and area of lacunae were quantitated microscopically with a digital image analyzer.
An other experiment was designed to study the effects of components of Pla on osteoclastic bone resorption activity. Osteoclasts attached to bone slices were placed at the bottom of a chamber which had been Pla cultured for 24 h above a partition membrane, and co-cultured for another 48 h.
In pre-seeded with 10^' cells group, the number and area of resorption lacunae was significantly decreased as compared to the control. In the co -culture using a partition chamber, no significant differences were found among the groups.
These findings suggest that periodontal ligament cells can inhibit osteoclastic bone resorption activity under contact culture conditions.

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The aim of this study was to clarify the effect of cell migration and tissue regeneration in the process of wound healing using chitin (poly-metric N -acetyl glucosamine) membranes .
First, chitin in the form of a sheet or a sponge and PTFE membrane were implanted subcutaneously in the rat abdomen, according to the wound heaing chamber method. SEM views of the membranes, which faced proliferating connective tissue, showed cell adherence to the chitin, which was slight on the 7th day and marked on the 14 th day. Cell numbers increased until 7 days, penetrating the chambers only through the chitin sheet.
Next, cortical plates of the rat mandibular body were denuded and bone defcts 0.5mm in depth were trepaned and the defect areas were then covered with a chitin sheet or a PTFE membrane. Histological findings were observed on the 7th and 14th days. It was found that the PTFE membrane was an effective physical barrier with connective tissue cell growth in the bone defects being inhibited, so that new bone formation was perfectly achieved.
Chitin exerted an effect on wound healing in efforts to achieve an accumulation of soft connective-tissue cells around the chitin surface and in the formation of new soft tissue even in the bone defects.
From these results, it was concluded that the chitin might promote cell migration and the proliferation of surrounding soft connective-tissue while exerting fewer direct effects as regards new bone formation

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The purpose of this study was to quantitatively clarify the stress distribution on oral tissue when toothbrushing force is transmitted through the bristles of a toothbrush.
We analysed dynamically two cases of toothbrush movement by the non-linear finite element method and the following results were obtained;
1. Toothbrushing movement in a gingiva model.
Two kinds of toothbrush, round end bristles and extremely tapered end bristles were each pressed 1 mm toward the periodontal tissue and set in motion horizontally with 6 mm reciprocation.
The result of analysis showed that the toothbrush with round end bristles generated a stress of 300-600g/cm² on the gingiva. On the other hand, the 130-200g/cm² from the toothbrush with extremely tapered end bristeles, was considerably lower than that of the former.
2. Entry of the bristle end into the periodontal pocket model.
We compared ease of entry into the periodontal pocket of two kinds of bristles, extremely tapered end bristles and lightly tapered end bristles.
Two bristles were tried for entrance into the periodontal pocket.
The result of analysis was that extremely tapered end bristles were easy to insert smoothly into the periodontal pocket, but lightly tapered end bristles were not.
The stress of lightly tapered end bristles on periodontal tissue was 6-7 times higher than that of extremely tapered end bristles.
In the case of the entry angle being changed, ease of entry was nearly equal to that of extremely tapered end bristles.

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Using two types of electric toothbrush and one type of conventional manual toothbrush, we compared their effectiveness in plaque removal by region as well as by tooth surface, to determine which type of brush is most appropriate for a particular patient and a particular region. The subjects of this study were a total of 11 persons comprised of paramedical personnel of this department and dental undergraduates. They were clinically healthy with no serious gingival problems. The subjects were asked to brush their teeth with each one of the three types of brush for two weeks running; then another type of brush for two more weeks for a total of six weeks. After each two -week trial period ended, plaque deposits were measured and examined in terms of the Plaque Index (Sillnes & Löe, 1967: PlI). For convenience, the oral cavity area was divided into six regions and plaque scores were scrutinized site by site. It was found that there were no statistically significant differences in the Plaque Index between the three different types of toothbrush as a whole. However, the use of electric brushes produced desirable results in the subjects whose plaque indices were notably high when they used the manual brush. For certain specific regions and tooth surfaces, the electric toothbrushes were more effective than the manual brush. These findings suggest that for those patients who are poor at removing plaques thoroughly with a manual toothbrush the use of an electric toothbrush should be recommended.

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The purpose of this study was to investigate the efficacy of a newly developed toothbrush with extremely tapered end bristles on plaque removal. Seventy five adults, between 23 and 52 years old, participated in this study. Subjects were instructed to brush their teeth at least twice a day and for more than three minutes per brushing using Scrub and Gottlieb's vertical method. Before starting this study, subjects were divided into groups by their plaque accumulation rate and the size of the interdental space of the experimental designed teeth. In addition, supragingival scaling and polishing of the teeth were performed on the experimental teeth and subjects were instructed to use one of the experimental toothbrushes (extremely tapered end bristles or rounded end bristles) during the following week. One week later, the presence of plaque on the experimental teeth was assessed in order to obtain the plaque accumulation rate. Another type of experimental toothbrush was used for the next one week period.
The results showed that the plaque index obtained using with the experimental toothbrush was lower than that achieved with the control toothbrush. It was confirmed that this new type of toothbrush with extremely tapered end bristles was significantly more effective in plaque removal than the toothbrush with rounded end bristles (p<0.05).

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The purpose of this clinical study was to evaluate the effects of a test liquid dentifrice containing 0.1% triclosan, 0.05% tranexamic acid and 0.05% dipotassium glycyrrhizinate on the control of dental plaque, and the prevention and/or improvement of periodontal disease in comparison with a placebo dentifrice.
Subjects were 60 adults who had no serious oral and systemic disease.
They were divided into two groups of equal size and performed toothbrushing twice a day for fuor weeks.
The results were summarized as follows:
1) The test liquid dentifrice was significantry superior to the placebo dentifrice in improving the gingival index (P<0.01) and the plaque index P<0.01).
(2) No particular side effects were observed during this clinical study.

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We investigated the localization and distribution of plaque bacteria, including periodontopathic bacteria, in supragingival and tooth-attached subgingival plaque using an immunohistochemical method.
Nine teeth with advanced periodontitis were extracted and processed into serial sections. They were stained with Brown-Brenn modified Gram stain and immunohistologically using labeled streptavidin biotin with specific rabbit antibodies against fifteen species of plaque bacteria. The localization and distribution of these bacterial species were examined under a light microscope.
All bacterial species examined were detected on tooth-attached subgingival plaque, and the staining patterns consisted of a variety of forms. Porphyromonas gingivalis was observed over the entire zone of tooth-attached subgingival plaque, located predominantly from the middle to outer layers at a distance from the tooth surface. The other bacterial species showed relatively individual localization in supragingival and/or tooth-attached subgingival plaque.
Actinomyces viscosus and Streptococcus sanguis, which were prominent in the earliest plaque formation, were observed not only in supragingival plaque but also in the middle and deep zones on tooth -attached subgingival plaque .
Immunohistological staining with species-specific antisera revealed the localization and distribution of various bacteria in dental plaque.

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This study was designed to estimate triclosan concentrations and the antibacterial effect of a liquid dentifrice in gingival crevices, in comparison to a conventional dentifrice.
The concentration of triclosan penetrating gingival crevices in front teeth was determined by the HPLC method after toothbrushing at molar sites.
To estimate the antibacterial effect, samples of gingival crevicular plaque were collected with sterilized paper-points from gingival crevices after toothbrushing for 60 seconds. The antibacterial effect was measured by counting colonies cultivated on blood agar medium (total bacterial count) and CFAT medium (Actinomyces naeslundii and Actinomyces viscosus). As a result, liquid dentifrice facilitated triclosan penetration into gingival crevices to a significant extent as compared with conventional dentifrice after toothbrushing for 10 and 20 seconds (p< 0.05).
Both liquid and conventional dentifrice significantly reduced total bacterial counts, (Actinomyces A. naeslundii, A. viscosus) and (A. viscosus, ) in gingival crevices as compared with the control after toothbrushing for 60 seconds (p<0.05, p<0.01).
In addition, the liquid dentifrice significantly reduced the tested bacterial counts as campared with the conventional dentifrice (p<0.05).
These findings suggest that the use of a liquid dentifrice is effective in keeping gingival crevices clean as compared with a conventional dentifrice.

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We have previously reported that irrigation of the inside of periodontal pockets with dilute solutions of Access®A is useful in the treatment of patients with adult periodontal disease. We observed the time course changes to 0, 2 and 4 weeks on clinical parameters and bacterial flora at 20-fold, 40-fold and 80-fold dilutions of Access®A in a double-blind test. A total of 145 patients with adult periodontitis and periodontal pockets of at least 4 mm were informed of the contents of this clinical trial and their consent was thus obtained. The irrigation of periodontal pockets was done with a Perio Pik™.
The solution was effective at all concentrations according to the clinical findings, and the 40-fold dilution was particularly effective. Irrigation with the solution at all of concentrations was effective against bacterial flora, and the 20-fold and 40-fold solutions were particularly effective. No side effects were observed at any of the concentrations used.
The results suggest that irrigating the inside of periodontal pockets with 20- to 40-fold dilutions of Access®A is very useful.

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In order to detect long term changes in periodontal status and periodontal disease treatment needs in an urban population, employees of two banks in Tokyo were subjected to periodontal survey by means of CPITN for nine years, from 1983 to 1992.
The prevalence rate of periodontal disease and the personal average number of sextants which showed periodontal disease were calculated using data from 1983, 1988 and 1992. The numbers of subjects and their average age in these yers were 616 (32.2 years old), 615 (33.2 years old) and 613 (34.1 years old) respectively. Statistical analysis proved that there was no difference in age distribution or average age among the years. From analysis of the rate of periodontal disease with CPITN, prevalences of diseases and the personal average number of sextants were found to have decreased longitudinally. With respect to treatment needs, the percentage of simple teatment needs increased longitudinally. This may reflect the success of oral care control systems in these two banks, in addition to heightened awareness of oral hygiene by the public.

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Dentin hypersensitivity has been a complex issue, as well as one of the least successfully treated problems in dentistry, for many years. In periodontal therapy especially, dentin hypersensitivity is a common problem following periodontal surgery and/or extensive root planing. For the treatment of dentin hypersensitivity, the application of desensitizing agents on the dentin surface has been widely used.
The purpose of the present study was to evaluate the clinical effect of a newly-developed desensitizing agent containing aluminum chloride and zinc sulfate (BMD) for dentin hypersensitivity in comparison with a commercial desensitizing agent containing zinc chloride (ZCS) as the control. A total of 56 teeth showing dentin hypersensitivity were examined in this study and were randomly assigned into two groups, i. e., a test group and a control group. Measurement of dentin hypersensitivity consisted of three clinical tests (cold water, cold air blast and tactile). The BMD was applied to the test teeth, and ZCS to the control teeth on day 0. The examinations were performed at baseline, just after application of the agent, and at day 7.
The intra- and inter-group analysis of the frequency of perceived pain induced by the three clinical stimuli revealed that both BMD and ZCS were effective for the treatment of dentin hypersensitivity. However, the average scores of the three clinical tests for the test group were much lower than that for the control group, suggesting that BMD might have greater efficiency than ZCS. Furthermore, comparisons of clinical improvements in perceived pain induced by the three clinical stimuli suggested that BMD might have better treatment efficiency, especially on the perceived pain induced by cold water and cold air blast, but not tactile.
Consequently, it is suggested that this newly -developed desensitizing agent containing aluminum chloride and zinc sulfate (BMD) is potentially quite clinically effective for dentin hypersensitivity.

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This paper reports the treatment of prepubertal periodontitis in a 6-year-old boy with granulocytopenia. Initially, the patient was found to have granulocytopenia accounting for neutrocytes in the 0-3% range of the total number of blood cells. Microbiological testing of subgingival plaque sample indentified Prevotella intermedia. Initial treatments included the extraction of the first and second primary teeth with grade 3 mobility, and scaling and root planing of the remaining teeth. The patient was treated with daily mouth washing and weekly irrigation of the periodontal pocket with a povidone-iodine solution. At 6 months after the initiation of the treatment, it was found that the permanent teeth had normal gingiva and the sulcus depth, and radiopraphic features showed no signs of periodontal breakdown.

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