The effects of loss and restoration of occlusal function on periodontal tissues were investigated using rats as a model system. In the occlusal loss group, the left maxillary molars were reduced by cutting the crowns to produce loss of occlusion. In the occlusal restoration group, dental restoration was performed on the crown of the molars 21 days after cutting. Untreated normal rats were used as the control group. In all three groups, the periodontal tissues of the first molar on the left mandible were routinely prepared for histopathological and histometrical analysis.
Rapid atrophic change was seen in the periodontal ligament due to the loss of occlusal function, and almost total loss of the functional arrangement of the periodontal ligament was observed 2-3 days after cutting the crown. At 4-5 days after cutting, new bone formation on the alveolar surface narrowed the periodontal space to about half that of the control animals. At 21 days after cutting most normal functional structures of the tissues had been lost. In the restoration group, bone resorption due to an increased number of osteoclasts was observed 1-2, days after restoration. The bone resorption tendeci to advance from the bone marrow side toward the periodontal ligament side, and the width of the periodontal space was seen to increase slowly. The number of fibroblasts increased and regeneration of fibers in the periodontal ligament occurred soon after the crown was restored. The process of periodontal ligament regeneration after recovery of occlusal function was relatively slow, but by 28 days most of the functional structures in the periodontal tissues had been restored. Thus, the periodontal tissues responded rapidly to the changes in occlusal functions. The different activities of fibroblasts, osteoblasts, osteoclasts and cementblasts during changes in occlusal functions were observed, and each cell type appeared to play an important specific role during the occlusal loss and restoration processes.

View full abstract

The present study was undertaken to identify human junctional epithelial cells immunocytochemically and ultrastructurally and then to establish the culture system of these cells. Primary cultures of cells were obtained from attached tissue explanted on type I collagen-coated dishes and immersed in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (FBS). Cells were subcultured with conditioned keratinocyte medium (KERATINOCYTE ™-SFM 0.09mmol/l Ca²⁺) on dishes coated with the basement membrane Matrigel ™ Each colony from attached tissue in primary culture consisted of closely packed epithelial like cells, in a paving stone arrangement . Cell-doubling time was 40.5 h. Junctional epithelium and gingival epithelium were compared immunocytochemically using monoclonal antibodies to AE 1, AE 3, and desmoplakin I + II, and by staining with Dolichos biflorus agglutinin (DBA) followed by immunofluorescent microscopy . Positive DBA staining in gingival tissues was found only in junctional epithelium, whereas positive staining for keratin and desmoplakin I+II was observed in both junctional epithelium and gingival epithelium . In the culture cells, DBA also reacted with cells from the attached tissue, but did not stain cells from gingival tissue. Anti desmoplakin I+II reacted with both cells, but the staining pattern was different. DBA-positive cultured epithelial cells from the attached tissue were poor in tonofilament bundles but contained abundant cytoplasmic organelles .
These findings suggested that junctional epithelial cells can be cultured under improved conditions and isolated from human gingival tissue.

View full abstract

In 1991, Dr. Gene McCoy reported the concept of dental compression syndrome (D. C. S.). The aim of this study was to investigate the clinical manifestations ofD. C. S.. We especially concentrated on the common signs of D. C. S. observed in teeth, and investigated the relationship between D. C. S. and periodontal disease. We selected 10 subjects aged 35-75 years (5 males and 5 females) who had wedge-shaped defects, unusual alveolar bone morphology in the oral cavity, such as exostosis and/or abfractions (D. C. S. group) and another 10 subjects aged 26-47 years (4males and 6 females) who did not have symptoms of D. C. S. as the control group. The clinical parameters assessed in this study were tooth mobility (M), buccal and lingual probing attachment level (B-PAL, L-PAL), area of occlusal contact (OC) and occlusalforce (OF). Measurements of M and B and L-PAL were made by PERIOTEST ® and with Color Probe ® . Measurements of OC and OF were made by DENTAL PRESCALE ® and OCCLUZER ® . The values obtained forthese clinical parameters were as follows: in the control group, M, 4.6±5.3; B-PAL, 2.2±0.8mm; L-PAL, 2.1±0. 9mm; OC, 20.9±5. 9mm² and OF, 304. 9±49. 9N, and in the D. C. S. group, M, 7.0±6.3; B-PAL, 4.0±1.4mm; L -PAL, 3.4±1.9 mm, OC, 53.8 ±44.2 mm² and OF, 578.4 ±293.4 N. The differences between the M values in the two groups was not significant. The difference between the B-PAL values was significant (p<0.01, by Student's t-test). There were significant differences between the two groups in L -PAL values for the anterior and the molar teeth p<0.05, by Student's t-test and Welch'st-test). (There were also significant differences between the groups in OC and OF values (p<0.05, by Welch's t -test). In the D. C. S. group, there were correlations p<0.01) between M and L-PAL, OC and OF, OC and L-PAL, and B-PAL and L-PAL. In the D. C. S. group, all premolars had wedge-shaped defects. It was concluded that B-PAL and L-PAL on anterior and molar teeth, and OC and OF were larger in the D. C. S. group than in the control group.

View full abstract

The matrix metalloproteinases are thought to play an important role in the destruction of connective tissue in periodontal disease. The monovalent ionophore, monensin, has been used in a procedure to immunolocalize metalloproteinases in cultured fibroblasts. Specifically this study investigated the effects of monensin on the immunocytochemistry of matrix metalloproteinase 3 (MMP-3) by comparing immunolocalization and gene expression in human periodontal ligament (PDL) cells. Cultured PDL cells were treated with and without IL-1β (1000 pg/ml) for 24 hours . Monensin (5 mM) was added to half the PDL cells for the last 3 hours of the incubation period. Immunolocalization of MMP-3 was performed by the avidin-biotin -peroxidase complex method . Gene expression of MMP-3 was investigated by the reverse transcriptase polymerase chain reaction (RT-PCR). Immunolocalization of MMP-3 in PDL cells was not observed when cells were not treated with monensin, even when treated with IL-1β. According to the results of RT-PCR, monensin did not alter MMP-3 gene expression stimulated with IL-1β. The numbers of MMP-3 producing cells and the amount of MMP-3 mRNA present did not conflict. Our Findings suggest that monensin treatment of PDL cells is an effective method of immunocytochemically visualizing MMP-3 without affecting MMP-3 message synthesis.

View full abstract

Kamiseii-san (kampo) has been known to be effective for periodontal disease from ancient times . This study was performed to investigate the effect of kampo on the alveolar bone resorption associated with experimental periodontitis induced with Actinomyces viscosus ATCC 15987 in hamsters . The amount of the bone resorption in the experimental animals was about half that in the controls . Kamiseii-san did not display any effect on the growth of the bacteria either in vivo or in vitro. These findings suggest that this agent had an inhibitory effect on alveolar bone resorption without affecting tha bacteria, and supports the traditional story. While the mechanism of the inhibition still remains unclear, it seems that some indirect action of Kamiseii-san may on alveolar bone metabolism result in inhibition.

View full abstract

The purpose of this study was to identify the bacterial species which are active at the bottom of human periodontal pockets, especially in the “plaque-free zone”. Thirty teeth with severe advanced adult periodontitis were extracted, and the plaque-free zones were investigated with specific antibodies against four periodontal disease -associated bacteria by a scanning immunoelectron microscopy method.
In the plaque-free zones, a few bacteria were observed by secondary electron image modes: spirochetes and rods were predominant. Several rods directly adhered to the root surface, and other bacterial cells adhered to the root surface mediated by glycocalyx-like materials. Porphyromonas gingivalis was actually found in the plaque-free zones in four of the seven samples examined, and TrePonerna denticola was detected in five of nine samples. The findings suggested that these two bacterial species could be related to the progression of adult periodontitis.
Prevotella intermedia occurred in the plaque-free zone in only one of the seven samples examined, and Actinornyces viscosus was identified in four of the seven samples. Based on these results, A . viscosus may have participated in plaque formation not only in the shallow portions but at the bottom of the periodontal pockets.
More than half of the number of the spirochetes and rods detected by secondary electron imaging in the plaque-free zones did not react positively with the four specific antibodies examined by back-scattered electron imaging. This suggests that many unidentified microorganisms were present in the plaque-free zones in addition to the above four bacterial species.

View full abstract

The purpose of this study was to analyzed the morphological characteristics of healthy periodontal status and occlusal conditions and to identity correlations between of the factors from these data themselves, namely occlusal stress or occlusal contact area, in relation with the location or environment of the tooth in dental arch or from the adjacent teeth.
Nine persons, age range 22-25 years, with healthy and harmonized periodontal status in the dental arch were selected as subjects of this study. Morphological data on the lower premolars and molars were obtained by making measurements on the study models made for each individual. Occlusion was tested with pressure-sensitive film (Dental Prescale ®) and electrically conductive film (T -Scan ®).
The following results were obtained : The second molars were found to exhibit the many occlusal stress and occlusal contact area. No significant correlations were found between the ratio of the width of the alveolar bone / crown and occlusal stress or occlusal contact area. The teeth shown to be 2.0 mm or more from the occlusal plane were recognized as the deepest point on the Spee curve, and accounted for the contact area of the average of all teeth. Their axes were inclined in the mesial or distal direction. No premature contact of any teeth was found with a T-scan system. Malpositioned and rotated teeth received less occlusal stress than teeth in the normal position, and accounted for one third of the contact area, less than the others.
These findings suggest that there were correlations between the morphological characteristics of the teeth or their location in the dental arch, in environment of adjacent teeth and occlusal stress and occlusal contact area.

View full abstract

Mouth-rinsing with oxydized water containing electrolytically generated chlorine has been shown to hinder dental plaque formation. However, mouth-rinsing has been associated with the problem of accelerating the deterioration of metallic restorations in the mouth. This study was undertaken to provide information necessary to evaluate the effects of rinsing by measuring the electrode potentials of metallic restorations in clinical situations.
The subjects consisted of 21 healthy volunteers between 23 and 40 years of age. Each subject was given 10ml of the oxydized water, asked to rinse vigorously for 10 seconds and repeat rinsing three times. Electrode potential measurements on all of the metallic restorations in the mouth were made before and immediately after each rinsing with a simple device equipped with a platinum microprobe.
In all cases mouth-rinsing with the oxydized water shifted the electrode potential of the metallic restorations in the mouth toward noble values, indicating oxidation. This finding suggested that, although the extent of the oxydation was unknown, proper utilization of oxydized water is of particular importance.
Further investigations are needed to fully develop and evaluate the potential of this mouth-rinsing.

View full abstract

This study was carried out to evaluate improvements in occlusal force after stabilization with a temporary splint, which is one of the steps in the initial preparation of mobile teeth using Dental Prescale ® (Fuji Photo Film Co., Ltd., Tokyo).
Ten patients with adult periodontal disease underwent examination of their periodontal tissue, and their occlusal force was determined using Dental Prescale ® after toothbrushing instruction, scaling and root planing. Stabilization with a temporary splint was then performed. The examination was performed again 2 weeks and 4 weeks, after stabilization with the temporary splint, and differences between the values before and after stabilization with the temporary splint were determined and statistically analyzed.
The results showed improvement individual values in the periodontal tissue measured. Statistically significant differences were observed between the periodontal tissue individual values before and 4 weeks after stabilization with the temporary splint. Testing of occlusion revealed an increase in occlusal area and occlusal force values after 4 weeks.
Thus, the results suggest amelioration of occlusion as the condition of the periodontal tissure improves in response to stabilization with a temporary splint.

View full abstract

Japanese green tea has been known to have an anticarious action and a halitosis-preventing action. The active ingredient, catechin, has been reported to have antibacterial, plaque-f ormation-suppressant and gingivitis-preventing activity.
The purpuse of this study was to investigate the effect of periodontal pocket irrigation with tea extract on clinical signs and subgingival bacterial flora. After scaling and root planing, periodontal pocket irrigation with a green tea extract solution was performed on 10 patients with periodontitis, and changes in clinical parameters and bacterial flora were evaluated in comparison with patients irrigated with sterile distilled water.
The results showed significantly better clinical findings in terms of GI, GCF, BOP in the group treated with green tea extract than in the group treated with sterile distilled water. Changes in bacterial flora revealed a greater decrease in motile rods as a proportion of all bacteria in the green tea extract group than in the sterile distilled water group.
These findings indicate that periodontal pocket irrigation with green tea extract solution may serve as useful adjunctive therapy for periodontitis.

View full abstract

An examination of the general condition and periodontal status, based on CPITN, of persons 40 to 45 years of age, was conducted in, Hatoyarna -machi, Hiki-gun, Saitama, to determine if there is a connection between the occurrence of periodontitis and life style or environment Information on life-style and environment was obtained by questionnaire A total of 184 adults were examined and asked to fill out the questionnaire in 1992 and 1993
The results of the examinations for these two years showed, 6 0% of the, subjects to be in code 0, 6 5% in code 1, 41 3% in code 2, 38 6% in code 3 and, 7 6% in code 4 in CPITN There were significant differences (x² test, p<0 05) between the CPITN code 0, 1 and 2 groups and the CPITN code 3 and 4 groups in the (1) living area and (2) sex items The results of the epidemiological investigation show that the occurrence and the progression of periodontitis are connected with life-style and general conditions.

View full abstract