To elucidate the regenerating process of junctional epithelium (JE) and discuss the functional aspects of regenerated JE (RJE), molar gingivae of 97 Wistar rats of 8-week-old were examined by EM at intervals up to 84 days following electrosurgery.
1. RJE was confirmed to derive from the oral epithelium (OE).
2. Undifferentiated keratinocytes migrating on the wound exhibited findings to indicate cellular motility, reconstruction and phagocytosis.
3. At 5 days, cells reaching the tooth surface near cemento-enamel junction formed hemidesmosome against intervening exudates.
4. At 7 days, epithelial attachment consisting of a basal lamina and hemidesmosomes was revealed. Cells with direct attachment to the tooth appeared to replace those with intervening exudates from apical to coronal. A sequence to form a long epithelial attachment typical to JE was traced on these cells. Elongated epithelial cells lateral to a juxta-tooth layer showed dilated intercellular spaces and began to contain prominent Golgi complexes and cytoplasmic vacuoles.
5. By 21 days, the epithelial architecture essential to rat molars was almost completely restored, but, after 14-28 days, the cells occupying the coronal portion of RJE were provided with organelles indicative of differentiation toward keratinized OE in addition to numerous cytoplasmic vacuoles.
6. After 42 days, the ultrastructure of RJE was indistinguishable from that before surgery. The cytoplasmic vacuoles, in particular, displayed the morphology, distribution and intimate relationship with lysosmes identical to those of controls, and were regarded to represent “phagosomes”. It seems that various findings specific to JE are due to the environmental rather than to a predetermined nature, and RJE might also play a defensive function through the endocytic-vacuolar system as suggested for normal JE.

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The object of present investigation was to examine the levels of various immunoglobulins (IgG, IgA, IgM) in dog gingiva at different stages of gingivitis and compare with those of healthy gingiva.
To obtain healthy gingiva, toothbrushing was continued for 6 weeks and mouth washing by 0.2% chlorhexidine (CHX) was carried out during the first week. After establishment of a clinically healthy gingiva in dog, the experimental gingivitis was induced by floss silk ligature in order to accelerate plaque accumulation for 1 week, 1 and 3 months. The excised gingiva from 4 dogs was prepared as follows: 1) powdering of the gingival tissues by adding liquid nitrogen, 2) dissolving in PBS, 3) freezing and thawing, 4) homogenization, 5) shaking, 6) sonication, 7) centrifugation. IgG, IgA, IgM and albumin were purified from dog serum by gel filtration and ion exchange chromatography, and specific antiserum was produced in rabbit.
The amounts of IgG and albumin in the gingival extracts were measured by single radial immunodiffusion, and those of IgA and IgM by electroimmunoassay.
The following conclusions were obtained:
1) The levels of IgG, IgA and IgM in each inflammatory stage were higher than those of the control, respectively, but the increase in IgA was statistically not significant. IgG level reached the maximum at the established lesion, and that of IgM at the initial lesion.
2) By correcting with gingival albumin, each amount of gingival immunoglobulins derived from serum was calculated. Consequently, the presence of IgG and IgA originated from the gingival tissue was confirmed.
3) The increased ratio of IgM to IgG at the initial lesion as compared with the control suggests the presence and enhancement of IgM originated from the gingival tissue.

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The metabolism of glycosaminoglycans (GAGs) was studied in the development of the periodontitis in dogs. Periodontitis was induced by silk ligature placement in the gingival crevices. The gingiva showed various signs of inflammation. Acute destructive gingivitis was observed shortly after ligature placement and developed into the complicated phase which consisted of less acute inflammatory responses in the gingiva and periodontium on day 7 and 10. And chronic periodontitis with alveolar bone destruction was established from day 20 to 90 after ligature placement.
The healthy gingiva contained much higher amounts of hyaluronic acid (HA) and dermatan sulfate (DS), and lower amounts of heparan sulfate (HS) and chondroitin sulfate (CS). HA content in the inflamed gingiva was lower than that in the control on day 3, 7 and 10. DS content was also lower in the inflamed gingiva on day 3 and 7. Then, HA and DS restored to the control levels. On the other hand, CS and HS content were always higher in the inflamed gingiva.
Insoluble collagen and total collagen decreased, but soluble collagen increased in the inflamed gingiva during the entire experiment. The increase of soluble collagen was drastic in acute destructive gingivitis.
These above findings suggested that the destruction of extracellular matrix happened in the acute destructive phase, and tissue repair and destruction coexisted in the complicated phase.
High activities of β-glucuronidase and UDP-glucose dehydrogenase and high amount of [³H]-glucosamine incorporation into GAGs were found on day 10. It was suggested that the degradation and the synthesis of GAGs might be markedly stimulated in the gingiva of the complicated phase.
Heparin was detected in the gingiva of the chronic inflammation with alveolar bone destruction, but was not detected in the healthy gingiva and in the acute destructive inflammatory gingiva. It was suggested that heparin might be one of the important bone-resorption stimulating factors.

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Two hundred and sixty-nine teeth were used for studying the relation between the level of existing periodontal supporting tissues and the area of the root surface. The new method developed by improving the so-called membrane technique is simple and easy to employ.
The root was coated with vinyl acetate solution twice. The same coating procedure was repeated with alpha-cyanoacrylate monomer. After setting, the membrane was stripped off from the root surface using a disposable blade. The outline of the removed membrane was drawn on the tracing paper and enlarged 10 times photographically. Transparent film with grids (2mm×2mm) was then laid on the enlarged membrane, and the area was calculated by counting the grids. Prior to this procedure, the reproducibility of this method was evaluated: acrylic cylindrical test body (8.0mm diameter, 10.0mm height) was measured 10 times on the same way described above.
The difference between measured and calculated value was 4.2±0.3% and the coefficient of variability was 0.27%. These results indicate that this method is highly reproducible.
The means of the total area of root surface were as follows: upper central incisor: 203.0mm², upper lateral incisor: 199.0mm², upper canine: 291.4mm², the upper first premolar: 252.1mm², the upper second premolar: 243.3mm², the upper first molar: 494.5mm², the upper second molar: 421.3mm², lower central incisor: 175.0mm², lower lateral incisor 193.0mm², lower canine: 246.0mm², the lower first premolar: 221.6mm², the lower second premolar: 234.1mm², the lower first molar: 390.9mm², the second molar: 347.1mm².
On the upper jaw, there were neither statistically different between the total area of root surface of central incisor and of lateral incisor, not between of the upper first premolar and of the upper second premolar. On the lower jaw no statistical differences were found between the total area of root surface of the canine and of the first premolar, nor between of the first premolar and of the second premolar.

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The purpose of this investigation was to study the relation between the level of existing periodontal supporting tissues when involved with periodontal disease and the area of root surface.
The root length from cemento-enamel junction to the apex of the root was divided into four equal parts. The root surface area of each divided part was measured by the method described in the part I.
The result were as follows:
1) In upper and lower premolars the proportion of the root surface area of each divided part to total root surface area decreased with approaching to the apex.
In other teeth than premolars the part of a quarter to half length of the root from cemento-enamel junction was the largest of all the four divided apex to a quarter length of the apex was the smallest.
2) The proportion of the root surface area corresponding with the distance from the apex to each divided part decreased more in upper and lower premolars than in any other teeth.
3) The root surface area from half length of the apex was approximately 43-44 % of the total root surface area.
4) The first and the second premolars in upper and lower were similar to each other in their total root surface area and in root surface area corresponding with the distance from the apex to each divided part.
5) The canine tooth in upper and lower jaws has the largest remaining root surface area corresponding with the decrease in attachment level of all the single rooted teeth.

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The purpose of this study was to investigate the clinical effect of K dentifrice containing three types of active agents on the improvement of periodontal disease. These agents are sodium chloride, ε-amino caproic acid and aluminium chlorohydroxy allantoinate. Also the effect of toothbrushes having different hardness of bristle was examined.
Forty-three outpatients were divided into 4 groups: Group 1, K dentifrice and S brush; Group 2, B dentifrice (placebo) and S brush; Group 3, K dentifrice and M brush; and Group 4, B dentifrice and M brush. The tooth-brushing was performed by all subjects with the Rolling method three times a day for two weeks.
The clinical effect was observed using analysis of variance for P-M-A index reduction ratio of the score at the initial examination to the score one and two weeks after.
The results showed a statistically significant (P<0.01) difference between K and B dentifrices. The K dentifrice was superior to the B dentifrice. After two weeks the mean P-M-A index reduction ratio of the K dentifrice and B dentifrice were 47.6% and 36.8%, respectively.
There was no difference between toothbrushes S and M. These results showed that K dentifrice containing sodium chloride, ε-amino caproic acid and aluminium chlorohydroxy allantoinate was effective for the improvement of periodontal disease.

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