To clarify the mechanism of lodging and retention of B cells in inflammatory lesions, we examined the adhesive interaction of B lineage cell lines with extracellular matrices, fibronectin and hyaluronate. The binding abilities of PMA-stimulated B lineage cell lines (CH 12 and BCL₁) to the extracellular matrices were examined first. PMA stimulation induced significant binding not only to hyaluronate, but also to fibronectin. But the kinetics of binding to these extracellular matrices are different. Binding to fibronectin rapidly increased for 4 hours and then declined gradually. On the other hand, binding abillity to hyaluronate was rapidly lost in the first 4 hours and increased slowly up to 20 hours. Blocking experiments with mAbs specific for cell adhesion molecules were performed to clarify the molecular mechanisms involved in the binding to these two extracellular matrices. It was demonstrated that fibronectin binding was mediated by Very Late Antigen-4 (VLA-4), which belongs to the Integrin family of cell adhesion molecules, and hyaluronate binding was mediated by the CD 44 molecule. FCM analysis demonstrated that surface expression of CD 44 was increased after 16 hour-PMA stimulation, although that of VLA-4 was not affected by PMA stimulation. The adherence to these extracellular matrices was also induced by IL-5 and LPS, though it took 3 or 4 days to induce maximum binding ability to hyaluronate. With these findings, we then examined the adhesion of the B lineage cells to stromal cells. The blocking experiments utilizing mAbs specific to cell adhesion molecules, in the case of 4 hour-stimulation with PMA, revealed that B cells bound to the stromal cell line, BMS 2, mainly with VLA-4. But in the case of 16 hour-stimulation with PMA, involvement of VLA-4 was rather decreased and CD 44 played a major role in the binding of B cells to the stromal cells. In this report, we has demonstrated for the frst time that IL-5 in inflammatory sites or LPS in sites of infection can activate B cells to bind to two different extracellular matrices, and reciprocal utilization of VLA-4 and CD 44 in accordance with B cell activation can play a significant role in attachment and retention of B cells by stromal cells at the site of inflammation.

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The present study was performed to evaluate the effect of using P₂0₅-Mg0-Si0₂-CaF-system glass ceramics in combination with a fibrous collagen membrane in guided tissue regeneration (GTR) for periodontal treatment under conditions similar to those of human periodontal disease. After preparing infrabony defects at the approximal surfaces of 19 molar teeth in 2 monkeys, root surfaces were contaminated with plaque for 4 weeks and the experimental sites were assigned into following four groups, Control group: flap operation alone, Group 1: flap operation with implantation of glass ceramic granules, Group 2: guided tissue regeneration using a fibrous collagen membrane, Group 3: implantation of glass ceramic granules in combination with GTR technique using fibrous collagen membrane.
Periodontal condition was observed clinically for 12 weeks.
After twelve weeks, the animals were sacrificed and all the experimental sites were subjected to histopathological observation using non-decalcified preparations.
The follwing results were obtained:
1. In Control Group and Group 1, little newly formed bone and connective tissue attachment was seen.
2. In Group 2, the apical extension of the junctional epithelium was reduced in comparison with group 1 and regeneration of bone and connective tissue attachment was seen.
3. In Group 3, the apical migration of the junctional epithelium was the least of the four groups . Furthermor, the glass ceramic granules had not dropped out. Bone regeneration was seen in a more coronary portion of the footh than in Group 2.
These results suggest that using glass ceramic granules with a fibrous collagen membrane, as part of the GTR technique, employed will provide effective periodontal treatment.

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The aim of this study was to investigate the effects of transforming growth factor-β A (TGF-β A) and on the regulation mechanisms of the differentiation of the periodontal ligament cells.
Periodontal ligament cells were isolated from 3 beagle's premolars. The cells which were subcultured on the eighth generation were used in this study. The cells were stimulated with various concentrations (0.01, 0.1, 1.0, 5.0, 10.0 ng/ml) of TGF-β A, and the cell proliferation and ALPase activity were assesed at 2, 4, 6 and 9 days following the treatment with TGF-β A. Immunoreactivity of and -proliferation cell nuclear antigen (PCNA) antibody and morphological cell-spreading were assessed at 5, 8, 12, 24 and 48 hours following the stimulation with 0.01 ng/ml TGF-β A.
Cell proliferation and ALPase activity were demonstrated bifunctional reaction, facilitated in lower concentrations (0.01, 0.1 ng/ml), conversely inhibited in higher concentrations (over 5.0 ng/ ml). The stimulation with 0.01 ng/ml TGF-β A immunoreactivity of PCNA were significantly higher than the control after 5 hours. Cellular processes tended to elongate axially by the treatment with TGF-β after 5 hours.
In summary, TGF-β may play as a regulatory factor and induce the differentiation of periodontal ligament cells into osteogenical cells. Therefore, it was suggested that TGF-β is involved in the mechanisms of the periodontal ligament homeostasis.

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The aim of this study was to examine the association of periodontal health with cigarette smoking. One hundred and sixty-seven male employees of a chemical factory in Osaka prefecture (20. `58 yr of age, 97 smokers, 15 ex-smokers and 55 non -smokers) participated in this study . The periodontal condition of the subjects was assessed with the CPITN. The subjects also answered a questionnaire on smoking habits and the frequency of toothbrushings. The percentage of persons affected was significantly associated with smoking habits (P< 0.05). Non-smokers showed a significantly greater mean number of sextants with code 0 than did smokers (P<0.001). The mean number of sextants with code 3 in smokers was greater than that in non-smokers (P<0.01). An increase in the mean number of sextants with code 3 was observed in younger smokers as compared to non-smokers. The mean numbers of DMF teeth and daily toothbrushings in smokers were similar to those in non-smokers. These results suggest that cigarette smoking is a risk factor which influences periodontal health.

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The purpose of the present study was to investigate histologically and histometrically the effect of periapical lesions on the state of periodontal lesions in rats.
Experimental animals were divided into Groups A, B, C, a, b and c. In all animals, a nylon thread was inserted into the interdental area between the right maxillary first and second molars (insertion side), whereas the interdental area of the left maxilla received no insertion (non-insertion side). Then, the animals of Groups A, B and C were killed at 4, 8 and 12 weeks after the nylon thread insertion, respectively. In Groups a, b and c, pulpal exposure was performed in both the right and left maxillary first molars, immediately after, 4 weeks after, and 8 weeks after the nylon insertion, respectively. The exposed area was left open. The animals of Groups a, b and c were killed at 4, 8 and 12 weeks after the nylon thread insertion, respectively. The interdental area between the right maxillary first and second molars, the periapical area of the distal root of the first molar, and the interradicular area of this root were examined histologically. Furthermore, the distance between the cementoenamel junc-tion and alveolar bone crest of the interdental area was measured histometrically.
Histological findings: In Groups A, B and C, the insertion sides showed slight periodontal lesions but no periapical changes, while the non-insertion sides exhibited no changes. In Group a, the insertion sides showed slight periodontal and periapical lesions, and inflammation and alveolar bone resorption in the interradicular area. In Groups b and c, the insertion sides exhibited moderate periodontal and periapical lesions, and inflammation and bone resorption in the interradicular area. In Groups a, b and c, the non-insertion sides showed periapical lesions but no periodontal changes.
Histometrical findings : On insertion sides, the distance between the cementoenamel junction and alveolar bone crest of the interdental area of Group a was the same as that of Group A, meanwhile the distance in Groups b and c was greater than that of Groups B and C, respectively.
The results of the present study suggest that periodontal lesions may develop when periapical lesions are present.

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The purpose of this study was to investigate the effects of differences in the vibration of an electric toothbrush and the hardness of electric toothbrush bristles on plaque removal and toothbrushing pressure. Nine electric toothbrushes, which differed in the frequency of vibrations (1, 000cpm, 2, 000cpm, 3, 000cpm) and bristle hardness (soft, mdium, hard) were used in this study.
Nine subjects participated in the experiment. Plaque scoring was carried out before and after toothbrushing, and the plaque removal rate was calculated. Toothbrushing pressure was determined. Side effects of their usage were also checked after toothbrushing.
The results were as follows:
1. Statistically significant differences in plaque removal from mesial tooth surfaces were found among the frequencies of vibrations and the hardness of electric toothbrush bristle (p<0.05).
2. Electric toothbrushes with a lower frequency of vibrations showed higher toothbrushing pressures (p<0.05).
3. The harder toothbrushes were used the lower PCR by O'Leary et al. (p<0.05).
4. Erectric toothbrushes with vibrations of 2, 000 cpm showes no gingival injury or bleeding.

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The application of Erbium YAG laser has been investigated recently in the dental field. The laser irradiation of Er: YAG does less damage to hard and soft tissues adjacent to the target site than that of CO₂ or Nd: YAG. Our previous experiments showed that this laser was able to remove subgingival calculus effectively at the energy density of 7.1-10.6J/cm² with water irrigation in vitro. The purpose of this study was to evaluate the bactericidal effect on periodontopathic bacteria at the energy density suitable for scaling. Porphyromonas gingivalis or Actinobacillus actinomycetemcomitans, which had been already spread over the surface of Tripticase-Soy Blood (TS) or Brain Heart Infusion (BHI) agar plates, was exposed to single pulse laser irradiation at the energy density of 0.04-2.6J/cm² and the growth of bacterial colonies was examined after anaerobic culture. One P. gingivalis colony was also exposed to single pulse laser irradiation at the energy density of 1.8, 3.5, 7.1, 10.6J/cm². Then the irradiated colonies were subcultured anaerobically and colony forming unit was counted . In results, the growth of P. gingivalis and A. actinomycetemcomitans was clearly inhibited at the irradiated site at the energy density of 0.3J/cm² and higher. In the case of single pulse laser irradiation to one P. gingivalis colony, the colony forming unit at the energy density of 7.1, 10.6J/cm² was significantly less than control. These results suggest that Er: YAG laser has a high potential of bactericidal effect on periodontopathic bacteria at the energy density suitable for scaling.

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Human and avian osteoclasts contain estrogen receptors and respond physiologically to estrogens. The evidence suggests that inhibition of bone resorption by estrogens is due to a direct estrogen effect on osteoclasts. To examine the possible involvement of estrogen in regulating the differentiation of hemopoietic stem cells into osteoclasts, hemopoietic stem cells from a mouse spleen were treated with 17 β-estradiol, and the proportion of multinucleated cells with a tartrate-resistant acid phosphatase (TRAP) activity was determined.
The proportion of TRAP-positive multinucleated cells was increased by exposure to 1 α, 25-dihydroxyvitamin D₃. The highest proportion was induced when the cells were cultured for 5 days and subsequently exposed to 1 α, 25-dihydroxyvitamin D₃ for 3 days. Simultaneous treatment of the cells with 17 β-estradiol for 3 days at physiological concentra- . A tions (10^-12-10^-9 M) resulted in a decrease in the proportion of TRAP-positive multinucleated cells in a dose-dependent manner.
The results indicate that treatment of hemopoietic stem cells from a mouse spleen with 17 β-estradiol at physiological concentrations inhib- . A ited differentiation of the cells into osteoclast-like cells. This suggests a direct response of estrogens to cells of the osteoclast lineage and the regulation of differentiation of these cells by estrogens.

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It has been suggested that in periodontal disease some bacteria can be regarded as suspected pathogens. The purpose of this study was to describe the microflora and clinical parameters of patients with adult periodontitis. Five patients 30 to 48 years of age were studied. All of them had a 5 mm or greater probing depth at a minimum of two sites, with a typical clinical picture of adult periodontitis. The DMDx ® Test was used to detect Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi). Enzyme -linked immuno sorbent assay was used to analyze peripheral blood antibody levels against Aa, Pg and Pi. As a result, all 5 patients responded well to initial treatment. The detected levels of Aa, Pg and Pi decreased, and the levels of antibody against them declined after initial treatment, which included plaque control and scaling. Thus, clinical status was well correlated with detected levels of pathogenic bacteria and systemic antibody production. Examination of subgingival microflora and host immuno responses may provide helpful information for clinical diagnosis and treatment.

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With recent advances in examination and treatment methods, it has become possible to treat and prevent periodontal disease. A new treatment modality (type I) which emphasizes etiology -related therapies more than conventional treat -ment (type II), was introduced into the Japanese Health Insurance Service System in 1985 . The purpose of this study was to compare the results of using these two treatment modalities .
All data used in this study were collected from 10 private practitioners. Twenty sets of X-ray films and protocols were randomly chosen from patient groups undergoing type I or type II periodontal treatment. Clinical parameters and measurements before and after treatment were compared .
The results were as follows:
1. O'Leary's Plaque Control Record after treatment was significantly lower in patients treated by the type I modality than in patients treated by the type II treatment modality .
2. Bleeding on probing was initially greater in patients receiving type I treatment. After treatment, there was no significant difference between the two groups.
3. Initial bone loss was greater in the patients undergoing type I treatment.
It was concluded from these results that type I treatment is effective despite the tendency for patients undergoing the type I modality to be more advanced than those treated by type II.

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This study was performed to detect patients at risk for future progression of periodontal disease and to examine the characterisitcs of such patients. Thirty-three subjects who had paticipated in an initial preparation and maintenance care program for five years after reevaluation were randomly selected. Clinical parameters were collected at the time of the baseline examination, re-evaluation examination and annual examinations during the maintenance phase. We defined deteriorated sites as sites with a greater than 2 mm increase in probing depth during the period of the study and a residual probing depth of more than 4mm at the examination five years after re-evaluation. The percentage of the deteriorated sites was calculated in each patient. The deterioration ratio ranged from 0% to 28.7%. Six patients (18.2%) had a deterioration ratio greater than 10%, and 57.7% of all deteriorative sites were concentrated in these patients. The outcome of clinical parameters in patients with high deterioration ratios was examined, but in the present study, no clinical parameter had the ability to predict patients at risk for future progression of periodontal disease.

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The purpose of this study was to clinicaly evaluate a biodegradable membrane purified from collagen, which has been used in the guided tissue regeneration technique (GTR technique) to treat vertical bone defects. The GTR technique was applied during routine flap surgery in 31 patients with vertical bone defects diagnosed as having periodontitis and requiring surgical treatment following initial preparation. After reflection and reversion with mucoperiosteal flaps, the collagen membrane was positioned on the bone defect, the gingival flap was restored, and then suturing was performed. The results of the clinial evaluations 3 and 6 months postoperatively were compared with preoperative findings. At 3 months there was an increase in bone change volume and attachment gain of 1.15 and 1.52±1.81 mm, respectively, and a decrease in pocket depth of 2.75±1.54 mm, while at 6 months there was an increase in bone change volume and attachment gain of 1.26 and 1.68±1.75 mm, respectively, a decrease in depth of 2.84±1.54 mm. The above results suggested that application of the collagen membrane to the GTR technique for the purpose of periodontal regeneration will be useful.

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