The purposes of this study were to observe morphological changes in rat periodontal tissues related to essential and pathological senescence, and to demonstrate the movement of type I & III collagens which accompany senescence. Eight-week -old male Wistar rats (20 in total) were used, and given powdered feed. We observed changes in the maxillary interproximal periodontium time-pathologically by using H-E staining and the picrosirius -polarization method . According to the results of the picrosirius-polarization method, type I collagen turns a yellow. red color, while type III shows up as a greenish color.
1) Up until 96 weeks of age, continuous physiological distal drift and eruption of molars were found. Downgrowth of the epithelial attachment progressed between 48 and 72 weeks of age. Resorption of bone on the mesial alveolar wall and apposition on the distal wall were characteristic. It was suggested that the greater cellular cemental apposition seen in the apical region was a response to passive eruption. After 72 weeks mesial tipping was suggested.
2) Essential senescent change consisted of reductions in cell numbers; fibroblasts, cement cells and bone cells were reduced between 24 weeks and 48 weeks of age. At the middle of the periodontal ligament especially, this phenomenon was distinct. However around the hard tissue, cells were regularly arranged.
3) Observations under the polarization microscope showed that periodontal ligament fibers became mature between 8 and 24 weeks of age. Type I collagen was always dominant and increased with the progression of senescence. At 96 weeks a reduction in type I collagen was observed. Above the alveolar bone and under the furcation, type III collagen was found, suggesting remodelling accompanying the eruption.
4) Pathological changes were followed; cementicle, absorption of cementum and inflammation by food impaction.

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Periodontal pockets, depth are more than 6 mm in patients with adult periodontitis have been treated by local administration of minocycline-containing collagen pellets (M-P group), lysozyme chloridecontaining pellets (L-P group) or combination of M -P and L-P (M+L group). The effects of the treatment were assessed in terms of clinical, microbiological and biochemical parameters before treatment, and 1, 4 and 8 weeks after treatment. Untreated pockets (control group) and those treated by root planing (RP group) served as controls. The results showed that treatment with M-P reduced bacterial density and changed bacterial composition of periodontal pockets, and leading to improvement of clinical symptoms. The effects were similar to those obtained by root planing and potentiated by combined administration of collagen pellets containing lysozyme chloride. The effects of combined M-P and L-P were also demonstrated by overall assessment on the basis of microbiological and biochemical parameters. The above findings suggested that the local administration of combinations of antibiotics and anti-inflammatory agents using a slow-release drug delivery system are effective in the treatment of periodontal disease.

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The membrane potential of human fibroblasts derived from periodontal ligament (PDL) was measured with a micro-electrode to investigate the electrophysiological changes induced by biological mediators. Eight freshly extracted teeth were obtained from 7 patients. The whole tooth or only the periodontal ligament was cultured in Dulbecco' s MEM, and 8 strains of PDLs were obtained. The resting potential of the PDLs subcultured in MEM was measured and the activated potentials stimulated with lipopolysaccharide (LPS; E. coli, 1-10 μg/ml) or human recombinant interleukin-1β (IL -1 β ; 50, 100, 200 pg/ml) were also measured . The resting membrane potential of the PDL ranged from -4.94 mV to -36.73 mV (mean -15.18 mV), and showed no difference after subculture nor among donors. The addition of LPS to the medium induced a minor change in the membrane potential shifting it to the hyperpolarizing side. The addition of IL-1 β to the medium caused marked hyperpolarization and this effect was dependent on the IL -1 β concentration . A high concentration of IL-1 β (100 pg/ml or 200 pg/ml) caused obvious hyper polarization (p<0.01), while the diluent of IL-1 β per se induced depolarization. (p<0.001)
This study shows that the measurement of PDL membrane potential is applicable to estimating changes in PDL caused by bioactive substances.

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Studies of periodontal treatments on intra-orally exposed root dentin were performed. In the first part of these studies, periodontitis-affected root dentin was compared with healthy root dentin in terms of attachment and growth of human gingival fibroblasts in vitro. In addition, these dentin specimens were histologically observed by light microscopy. Root dentin fragments (4. 4. 1mm) were prepared from extracted human healthy and periodontally-involved teeth. Each group consisted of 10 fragments. The root fragments were placed in Petri dishes and were seeded with ×10⁵/m_l fibroblasts in MEM containing 200 units/ml penicillin and 200 μg/m_l streptomycin followed by incubation for 96 h. The number of cells attached and grown on fragments were counted by light microscopy after they had been fixed and stained.
The results of this study show a tendency for the number of fibroblasts on periodontitis-affected root dentin to be somewhat fewer than on healthy root dentin, though this reduction was not statistically significant. Histopathologically, differences were barely detectable in either group but bacteria were observed in a few dentinal tubules in just two cases of periodontitis-affected teeth. Our results suggest that certein substances inhibit cell attachment enabling bacteria to invade periodontitis-affected root dentin.

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This study was performed to investigate methods of root treatment used to attach periodontal tissue on exposed root dentin.
Root dentin fragments (4. 4. 1mm) were prepared from extracted periodontally-involved teeth. After 0, 7, 14 or 28 days of intra-oral exposure, root fragments from each period were divided into three groups: 1) no treatment 2) slight root planing 3) exhaustive root planing. Then the root fragments were placed in Petri dishes and seeded with 1×10⁵/ ml human gingival fibroblasts in MEM containing 200units/ml penicillin and 200 μg/ml streptomycin, and incubated for 96 h. After the fragments had been fixed and stained, the number of cells which had attached and grown were counted by light microscopy. In addition, these dentin were histopathologically observed by light microscopy.
The results were as follows:
1) In the no treatment group, there were very few attached cells after 7 days of intra-oral exposure.
2) In the slight root planing group, few fibroblasts had attached and plaque persisted on a portion of the dentin surface in this group.
3) In the exhaustive root planing group, a large number of fibroblasts attached and there was no plaque on them. Our results suggest that, when root dentin surfaces are exposed intra-orally for more than a week, exhaustive root planing with a curette type scaler is necessary for the purpose of periodontal attachment.

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We studied the effects of lipopolysaccharide LPS) from Porphyromonas (Bacteroides) gingivalis and Prevotella (Bacteroides) intermedia, and interleukin-1 (IL-1) on production of collagen in cultured human fibroblasts. Fibroblasts were obtained from healthy gingiva, inflamed gingiva and healthy periodontal ligament. After the cells had reached confluence, they were incubated with LPS (final concentration: 10 μg/ml) or IL-1 (final concentration: 0.5, 5 μg/ml) or LPS (10 μg/ml) +IL-1 (0.5, 5 μg/ml) for up to 48 hours. Collagen levels in culture media were measured using Procollagen type IC-Peptid EIA Kit. Collagen levels were increased by stimulation with LPS or IL-1. Collagen levels were greatly increased by stimulation with LPS IL-1 as compared to those of stimulated by LPS or IL-1 alone. From these findings, it is suggested that LPS and/or IL-1 may promote collagen synthesis of fibroblasts in periodontal tissue in vivo.

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The present experiment was undertaken to clarify time differences in vivo in absorption process as a result of differences in the absorption, bioaffinity and the ratio of atelocollagen (which has excellent bioaffinity) to chitosan (which is slowly absorbed by tissue and accelerates wound healing), in gingival tissue. In order to develop an absorptive membrane for the guided tissue regeneration (GTR) technique, composite memberanes A (chitosan: collagen, 7: 3) and B (5: 5) (A.B. -CSK membrane) and a chitosan membrane (Chitosan 100% KSK membrane) were produced. Each membeane was inserted among the treated root surface and reflected gingival flap in male wistar rats. They were observed histopathologically 1, 3, 5, 7 and 14 days after surgery. The higher the chitosan content of the membrane, the sooner marked inflammatory cell infiltration was observed postoperatively. The adhesion of membranes with a high chitosan content to connective tissue was favorable. In such membranes, the inhibitory effect on epithelial migration acceleration of maturation of the connective tissue around the mambrane, as well as absorption, tended to be delayed. These results suggest that absorption of the membrane is affected by the ratio of the mixture.

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After several trial measuring devices had been built for evaluating the load of a tooth involved with periodontitis, a load measuring device was developed. With this newly developed mesuring device, the load on a mobile tooth with chronic marginal periodontitis could be evaluated and studied in terms of the relationship between the degree of tooth mobility and the destruction of alveolar bone. The results demonstrate that teeth of mobility class 1 can be moved by a load of about 43.2 g, class 2 by about 32.6 g and class 3 by about 21.1 g. As to the destruction of alveolar bone, the teeth which had bone destruction of degree 2 moved with a load of about 38.0 g, degree 3 with about 29.6 g and degree 4 with about 23.7 g.

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The purpose of this study was to compare a rapid diagnostic test (Perioscan™) results with periodontal conditions of the specified tooth surfaces for evaluating this test as a screening method in mass examination in Japanese factory workers. Probing depth, bleeding on probing, and calculus and plaque deposition at buccal and lingual surfaces of maxillary right and mandibular left first molars were assessed and recorded. After clinical examination, sub-gingival plaque was collected from the examined surfaces by a scaler. BANA hydrolysis by a subgingival plaque sample was measured on the BANA card test. The main results are as follows: 1. The percentage of tooth surfaces evaluated as test positive was 73.8%. 2. There was a significant association between the BANA test results and clinical periodontal indicators. However, the specificity is relatively lower than the sensitivity in this test. Thus, there is room for improvement in terms of the low specificity and in development of the sampling technique.

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The purpose of this study was to evaluate the healing process of periodontal tissue with inflammation induced by bacterial plaque after flap operation and guided tissue regeneration (GTR).
Four mongrel dogs were used. Periodontal defects were produced in mandibular 1st and 2nd premolars and 1 st molars. Dogs were treated by 2 different surgical methods, namely guided tissue regeneration (experimental group) and flap operation (control group).
Twenty four weeks after the operation, the dogs were sacrificed by overdosing with pentobarbital sodium. Histopathological studies were conducted. No oral hygiene was introduced in any of the experimental periods. The results were as follows:
1. Control group:
Numerous (1) b acterial plaque adhered the teeth.
Deep periodontal pockets had formed, (2a) nd the most apical cells of the junctional epithelium were at the most apical position of the planed root.
(3) Inflammatory cells were widely dispersed in connective tissues.
Bone (r4e) s orption was observed at the crest of the alveolaris.
2. Experimental group:
A small amou n (1t) of bacterial plaque was observed on the teeth.
The most a (p2i) c al cells of the junctional epithelium were approximately at the cementoenamel junction.
(3) Inflammatory cells were observed only within localized marginal areas adjacent to the epithelium of connective tissues.
New cementum f o (r4m) ation was observed along the surface of the planed root.
New bone formation was (5) o bserved at the crest of the alveolaris.
It was concluded that the new attachment obtained as a result of guided tissue regeneration served as a barrier against inflammatory tissue destructioncaused by bacterial plaque

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The purpose of this study was to examine ultrastructure of the border zone between long junctional epithelium (LJE) and the connective tissue attachment regenerated on a denuded dentin surface.
Two One-year-old beagle dogs were used. After a mucoperiosteal flap had been made, dentin surfaces were exposed with removal of buccal alveolar bone and permolar cementum. The root surfaces were divided into 2 groups. One group (M) was produced by covering the exposed bone surface adjacent to the roots with polycarbonate membrane while the other group (N) was not covered. Animals were sacrificed by perfusion of 1% glutaraldehyde 4 and 8 weeks after surgery, and periodontal tissue were decalcified, postfixed, and embedded in epon. Ultrathin sections were observed by transmission electron microscopy.
In the N group it was observed that 8 weeks after surgery the internal basal lamina of superficial LJE cells remained on the dentin surface beneath the apical LJE, and new cementum matrix had forme on the dentin surface. On the other hand, LJE cells of the M group were attached to all dentin surfaces, such that connective tissue reattachment had no yet occurred.
The results suggest that coronal migration of may be closely connected with new cenentum formation LJE cells.

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This study was designed to examine the ultrastructure of cementogenesis at dentin surfaces treated with hydrochloric acid (HCl)
The buccal aspects of the teeth of 2 one-year-old beagle dogs were used as experimental sites. After a mucoperiosteal flap had been made, buccal cortical bone was removed and the dentin surfaces were denuded by root planing. One half of the apical sites of these denuded dentin surfaces were treated with 0.3 N HC1 for 5min, and the gingival flap was then repositioned and sutured. Electron microscopial specimens were prepared up to 8 weeks after surgery and observed.
1. In the non-HC1 group, the predominant findings at 4 and 8 weeks after surgery were demineralized dentin substants, absorbed by odontoclasts, and exposed dentin matrix fibers interdigitating with newly formed cementum matrix fibers.
2. In the HC1 group, newly-formed cementum adhered directly to the dentin matrix decalcified by HC1 at 2 and 4 weeks after surgery. It was observed that newly-formed collagen fibers connected and/or interdigitated with dentin matrix fibers.
Our results suggest that new cementum is directly formed to dentin decalcified by HC1.

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The in vitro substantivity of minocycline hydrochloride (Mino-HCL) for untreated root surfaces affected by periodontal disease was examined by bioassay using Porophyromonas gingivalis (P. g.) and Hemophilus actinomycetemcomitans (H. a.) as test bacteria. Treatment was performed with Mino -HCl in aqueous solution at concentration of 10 mg/ ml for 10 min (10 mg 10 min group) and 50 μg/ml for 1 day (50 μg 1 day group) on the assumption of local application, and 5, μ g/ml for 7 days (5 μg 7 day group) on the assumption of systemic administration. The results showed that both the 10 mg 10 min group and the 50 μg 1 day group exhibited significantly higher antimicrobial activity against P. g. on day 0 (10 min), 7 and 14 after immersion of the root surface in physiological saline than did the 5, ug 7 day group. Antimicrobial activity against H. a. was significantly higher on days 7 and 14 in the 10 mg 10 min group than in the 5 μg 7 day group. The antimicrobial activity decreased significantly in the period from day 0 through day 7 during the course of study, while the 10 mg 10 min group and the 50 μg 1 day group exhibited no decrease in the antimicrobial activity from day 7 through day 14. The above results indicate that in treating the root surface affected by periodontal disease, greater substantivity of Mino-HC1 may be obtained with local application than with systemic administration.

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Self-setting apatite cement was investigated, to evaluate its use as a possible bone substitute, in mongrel dogs. Three osseous defects were prepated surgically in canine mandibles. Two osseous defects were filled self-setting apatite cement and granules of hydroxyapatite, respectively. The last defect was filled with nothing, as a control. The implant sites including one control were observed at 1 and 2 months postoperatively in light microscopic study. In any of the specimens prepared at any stage, appreciable foreign body responses were barely observed in the tissue around the set cement, and encapsulation of set cement by fibrous connective tissue was not found in the self-setting apatite cement group. The newly formed bone was noted to be directly deposited on the set cement at 2 months after implantation. Self-setting apatite cement was superior to granules of hydroxyapatite and the control in terms of recovery of bone height at 2 months after surgery. These results suggest that this cement is not only well tolerated by bone tissue and osteogenesis, but also well suited to the complicated bone defects seen in periodontal disease.

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Selvic has been reported to exist on the outer layer of the hypermineralized zone of exposed human cementum since then, much research has been conducted on the hypermineralized zone of exposed cementum. However, many questions regarding exposed cementum remain. One such question involves the classification of periodontitis in the six advanced, six moderate and six mild teeth (total-18 teeth). After extraction, we developed materials for study and investigated the hypermineralized zone in terms of attachment loss. We matched our results with other clinical findings. Using contact microradiography, examination of mineralization patterns and qualitative analysis of Ca and P with an Electron Probe Microanalyser (EPMA) revealed a higher concentration of both elements at the superficial layer of exposed cementum. The system used included an EPMA or Scanning Electron Microscope (SEM-NIHON -DENSHI JCXA-733 type) with applied Kevex-700 EDS. Our results suggest that contruction of the hypermineralized zone of cementum leads directly to progressive increases in attachment loss and reduc ed G.I., G.B.I, and mobility.
The appearance of small pits on neighboring exposed cementum in the setting of advanced disease in humans is acknowledged.
Observation by microradiography with COMPO to 2-3. μm of the hypermineralized zone revealed an average of 10, 4. μm. Further observation (Von Kossa calcium detection dying) of the line-motter inter-sharpie fibers on the outer layer of the cementum revealed them to be both small and large, as well as ball-shaped.

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The efficacy and the safety of 270 mg a day for 4 weeks of lysozyme chloride (L) on marginal periodontitis were compared with inactive placebo (P) in a multicentric double-blind study.
A total of test subjects was 311 cases (L group; 159 and P group: 152), and a tooth at maxillary labial symmetrical right and left site in these individuals were adopted for efficacy analysis.
Scaling before initial drug administration, and brushing throughout this study, were performed with all patients.
Bleeding on probing, gingival inflammation, mobility of the tooth, depth of periodontal pocket, amount of gingival crevicular fluid (GCF) were examined at the baseline, the second and the fourth week after the start of the drug administration. Prostaglandin E₂ (PGE₂) in GCF, and subgingival microorganisms were examined at the baseline and the fourth week. The global improvement rating were evaluated at the second and the fourth week, overall safety and usefulness were evaluated at the end of this study.
As to improvement rate for bleeding on probing, gingival inflammation, mobility of the tooth, pocket depth and PGE₂, significant difference was not observed between two groups. Significant reduction of GCF amount was found in the L group only. The proportion of motile microorganisms decreased significantly in the L group only. In the density of microorganisms, significant difference was found between the two groups.
In the global improvement rating at the fourth week and usefulness, the L group was significantly superior to the P group. Adverse reactions were observed in 13 cases in the L group, and 19 cases in the P group, but in overall safety there was no significant difference between the two groups.
Results in this study suggest that lysozyme chloride is a useful drug in patients with marginal periodontitis when it is taken with scaling and brushing.

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This study tested the effectiveness of a reciprocating electric toothbrush in removing supra-gingival plaque. Two different revolutions (2000, 3000 rpm) and two different brushing times (3min., 1.5 min.) were set up, and comparisons were made with a manual toothbrush in each condition. Ten adults with normal dental arch and healthy gingiva participated in this study. Plaque scores before and after brushing were assessed. The effects of a reciprocating electric toothbrush in removing supragingival plaque were almost the same as those of a manual toothbrush. For both electric and manual toothbrushes, plaque removal effects, especially on proximal surfaces, deteriorated when brushing time was short.

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This study tested the effectiveness of several different types of electric toothbrush for removal of supra-gingival plaque. Five different types of electric toothbrush were used, and comparisons were made among the conditions and with manual toothbrushing. Ten adults (meanage 23.6 years) with normal dentition and healthy gingiva participated in this study. Plaque score before and after brushing (3 min.) were assessed.
The rate of plaque removal of the counter rotational action powered toothbrush (INTERPLAK ®) was the highest among toothbrushes we tested. It showed better efficacy of plaque removal in the proximal and lingual areas.
The round tuft reciprocating toothbrush (PLAKCONTROL ®) showed a higher rate of palque removal than manual toothbrushing, and the effect of plaque removal in the proximal area was superior to that of the manual toothbrush. Another electric toothbrush we tested showed almost the same or a higher rate of plaque removal than the manual toothbrush.
In conclusion, several different types of electric toothbrush showed almost the same or higher effectiveness in plaque removal than manual toothbrushing. Our results indicate that toothbrushing with an electric toothbrush is considerably effective for supra-gingival plaque removal.

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A case of Wegener's granulomatosis which is first manifested itself as a granulomatous lesion of the gingiva is reported. Wegener's granulomatosis is characterized by a necrotic and granulomatous changes of the upper or lower respiratory tract, glomerulonephritis and disseminated small vessel vasculitis. This disease is defined as a auto-immunity disease recently.
Fourty three-year-old man was referred to the Nippon Dental University hospital with and unusual form of severe gingivitis and mastication problem. In the initial examination, severe swelling and flare of whole gingiva were observed. Those surfaces had granular or strawberry like structure (granular gingivitis). Severe alveolar bone resorption, periodontal pocket formations more than 7mm and severe tooth mobility were observed. The patient had intermittent pain in gingivitis region. In the laboratory findings, positive CRP and RA, slight increasing of PMNs number and decreasing of lymphocytes number were observed.
Two weeks later, severe swelling of right palpebra dacryohemorrhea, ulceration on the left temporal region and notal skin region were observed. Especially, the rhinorrhea with blood like secretion was also observed. The granulomatous lesion of the gingiva was changed to the ulcerative gingiva and could be observed a bone surface denudation. Deciduation of many teeth were occurred and residual teeth showed high mobility. In the lymphocyte subset analysis, T cell ratio in peripheral blood was decreased, B cell ratio was increased, NK cell ratio was extremely increased and the helper T cell/suppressor T cell ratio (H/S) was 1.8.
Four days later, this patient was ended in death due to the rapid fulminating downhill course in systemiccondition. This disease was diagnosed as Wegener's granulomatosis from results of autopsy.
The specific features of this case are following findings.
1. Granular gingivitis was an initial symptom instead of necrotic and granulomatous changes of the nasopharynx, 2. Acute necrotic changes of gingiva and oral mucosa, 3. The increasing of tooth mobility and the falling of teeth accompanying the progression of oral lesion, 4. Acute and fulminant granulomatouschanges of constitutional organs, 5. Decreasing of T cell ratio and increasing of B cell ratio in whole neutrophils, 6. Increasing of NK cell ration in whole neutrophils.
Above findings suggest that presence of putative periodontal pathogens is connected with the initiation of Wegener's granulomatosis.

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The purpose of this study was to investigate the effects of four electric toothbrushes and a manual toothbrush on plaque removal and toothbrushing pressure. Four electric toothbrushes (Plak Control ®BRAUN), Power toothbrush ® (NATIONAL ®, DENT. EX electric toothbrush ®) (LION), INTERPLAK ® (BAUSCH & LOMB) and a manual toothbrush (PROCT ® R-4 (M) (Sunstar)) were used in this study. The manual toothbrush was designed as follows: nylon bristles (0.20mm in diameter), round ends, 10mm in length, 3 rows, 23 tufts, straight handle.
Fifteen subjects participated in this experiment. Plaque scores were measured before and after toothbrushing, and plaque removal rates were claculated. The toothbrushing pressures were determined by modified Watanabe's method.
The results were as follows:
1. No statistically significant differences in total plaque removal were found among the four electric toothbrushes and a manual toothbrush.
2. Statistically significant differences in toothbrushing pressure were found between Power toothbrush (®a) nd INTERPLAK ®, a nd between PROCT ® and INTERPLAK ® . (p<0.05)
3. It was very difficult to remove plaque sufficiently from proximal tooth surfaces with an electric toothbrush.
4. Compared with a normal powered toothbrush, the counter rotational action powered toothbrush tended to cause more gingival injury.

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The purpose of this study was to evaluate the plaque removing effect of two electric toothbrushes and a conventional manual toothbrush, in normal and Periodontally involved models.
To investigate the basic ability to remove plaque from each tooth the brushing time, brushing method and other conditions were not regulated for each type of brush.
The plaque removing effect was determined by the percentage of plaque removed along the length of gingival margin.
There was no statistically significant difference among the two electric toothbrushes and the manual toothbrush. In the periodontally-involved model, the plaque removing effect was lower than that in the normal model. And the percentage of plaque removed at the anterior site was higher than that at the posterior site.

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