Bruxism is understood to be started by the abnormal tension of the masticatory function, to often cause occlusal trauma and to make destructive influences on the masticatory muscles and the temporomandibular joint. Howevear, the cause and the relationship between the central and peripheral nervous systems remain unsolved. In this study, the condition of the central nervous system was evaluated by brain waves, and relationship between occurrence of grinding and depth of sleep, difference in occurrence of grinding by bite plate and muscle relaxant, relationship between total muscle activetime and depth of sleep were investigated. The results showed that the grinding occurred in stage 2 and REM. In these stages of sleep, depth of sleep was not influenced by grinding. With bite plate and muscle relaxant, decrease in number of grinding with reduced action potential, together with decrease in total muscle active time were observed. In non-REM stage, change in brain waves occurred preceding grinding and the central nervous system was thought to be predominant.

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The purpose of this study was to examine the interaction between plaque bacteria and polymorphonuclear leukocytes (PMNs) in periodontal pockets with adult periodontitis. Six teeth from six patients with severe periodontitis were examined in this study. Prior to the biopsy, alkyl-α-cyanoacrylate monomer was applied to subject teeth and surrounding gingival tissue. The tooth with its surrounding gingival tissue was then carefully extracted. Ultrastructural studies were carried out to examine the interaction between subgingival plaque and PMN layers in the apical part of the periodontal pocket. Subgingival plaque adjacent to the PMN layer was comprised of coccoid, rodshaped and fusiform bacteria. Many cells possessed characteristics of gram-negative bacteria with a cytoplasmic membrane, a periplasmic space, peptidoglycan and an outer membrane. Small numbers of spirochetes were also found in this region. The intercellular matrix, numerous vesicle like structures, fibrillar matrix and test-tube brush like formation were observed in this region. The layer of PMNs was observed between the plaque and the pocket epithelium. PMNs in the interface engulfed gram-negative bacteria. Lysosomal granules seemed to be released into phagosomes and were discharged into the extracellular space. PMNs in the enlarged intercellular spaces of the pocket epithelium contained many lysosomal granules. No bacterial invasion in the intercellular space was observed. These data suggested that the mechanism by which PMNs responding to plaque play a role in tissue injury as well as protective efficacy.

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The present study was initiated to assess the relationship of elevated antibody levels to Actinobacillus actinomycetemcomitans infection and serotype distribution in patients with adult periodontitis, and to further elucidate the antigens responsible for antibody responses.
The dominant A. actinomycetemcomitans serotype isolated was serotype c. As a result of immunoblotting with sonicated antigens and patient sera, reactivity with serotype-specific antigens of serotype c was most frequently observed. When serum IgG titers to A. actinomycetemcomitans Y 4 LPS and fimbriae antigen from A. actinomycetemcomitans 310-a were assessed by ELISA, elevation of IgG titers was noted for patient sera. Immunoblotting revealed that the reactivities were specific to the purified antigens. A. actinomycetemcomitans serotype c may play a greater role than other serotypes in the pathogenesis and progression of adult periodontitis. The presence of specific antibody against the surface antigens of A. actinomycetemcomitans was further confirmed.

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The purpose of this study was to evaluate gingival recession of both marginal and Interdental gingiva. Gingival recession was measured by the standardized photograph technique from plaster casts of 39 patients who were in the periodontal maintenance phase and 10 healthy subjescts.
The degree of marginal recession was 1.19 mm in maintenance parients (M) and 0.03 mm in healthy subjects (H). Interdental recession was 3.17 mm (M) and 1.02 mm (H). Their values for Filling Ratio of Interdental Gingiva (FRIG) were 77.24% M and 96.91% (H).
From these results, the gingival scalloped form was classified into 3 types; High Scallop, Average Scallop and Flat. Thus an Interdental Gingival Form Index (I.G.F. Index), which indicates individual gingival form, was devised.
The I.G.F. Index, marginal recession, and FRIG made it possible to evaluate the recessional form of gingiva through the entire dentition numerically. In conclusion, it became possible to objectively evaluate esthetic aspects in pre-and post-treatment stages.

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The compositions of glycosaminoglycans (GAGs) in subgingival dental calculus were compared with those in supragingival dental calculus. Samples were obtained from 107 patients with periodontitis. GAG was extracted with 4M guanidine hydrochloride/ 50mM Tris-HC1 (pH 8.0) under nondemineralized and demineralized conditions from sub- or supragingival dental calculus. Separation and quantification of GAGs were performed by two dimensional electorophoresis on celluose acetate membrane; chondroitin sulfate isomers were analyzed by high-performance liquid chromatography. Major components of GAG in supragingival dental calculus were hyaluronic acid (17.5. μg/g dry wt.) but no sulfated GAG was detected. In subgingival dental calculus, in addition to hyalronic acid (26.7 μg/g), chondroitin sulfate (18.2. μg/g). Eand dermatan sulfate (9.3. μg/g) were detected. Most of the chondroitin sulfate in subgingival dental calculus was present as the 4-sulfated type. These results suggest that GAGs in subgingival dental calculus originate from gingival clevicular fluide components.

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Antigenic proteins of Actinobacillus actinomycetemcomitans (Y 4) were studied by two-dimensional electrophoresis and Western blot using IgGs from patients with periodontitis. The cells were ultrasonically disrupted and divided into three fractions by centrifugation: P-25 fraction (precipitates by 25, 000. g for 30 min.), ribosomal fraction, and S -100 fraction (supernatants by 100, 000. g for 2 hours). Each fraction was analyzed by two-dimensional electrophoresis and Western blot. 218, 44, and 216 protein spots were observed at the P-25, ribosomal, and S-100 fractions by two-dimensional electrophoresis on silver stains. Antigenic characterizations were performed using purified IgGs from 13 healthy subjects and 27 periodontitis patients. The results of Western blotting assay demonstrated that a 64 kDa protein from the ribosomal fraction reacted with various parts. Edgeways of the lower arch and whole spots of the 64 kDa protein reacted with samples from both healthy subjects and periodontitis patients. But edgeways of the upper arch reacted with 44% of IgGs from patients with periodontitis. Two antigenic substances from the ribosomal fraction which were not spot form but showed large diffuse reactivity on Western blot, reacted only with samples from periodontitis patients at a frequency similar to that of the upper arch 64 kDa protein. There were no specific periodontal disease antigens in either the P-25 or S -100 fraction in this study .

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We studied the effects of initial treatment on clinical parameters and subgingival microflora in patients willing to exercise optimal plaque control. Eleven patients (5 males and 6 females, mean age: 52.2 years) with moderately advanced periodontitis participated in this study. Patients were instructed an oral hygiene, and scaling and root planing were performed. Probing depth (PD), attachment level (AL), bleeding on probing (BOP) and subgingival microflora were examined at the time of the first examination, when the level of O'Leary's plaque control record had reached about 10% and when the instrumentation had finished. Microbiological status was evaluated by phase contrast microscopy and was classified into five groups: coccoid cells, rods, motile rods, spirochetes and others. Total number of microorganisms and the relative proportions of each group were calculated.
The following results were obtained:
All examined pockets were divided into two groups according to probing depth at the first examination, shallow group (PD. <3mm) and deep group (PD. <4mm). Marked improvement of all clinical parameters was observed in the deep group, in contrast, the shallow group exhibited only a slight general improvement. The relative proportion of coccoid cells increased within the period of initial treatment, whereas motile rods and spirochetes were reduced. This tendency was obvious in cases in which remarkable pocket reduction had occurred.

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We studied the effects of lipopolysaccharide LPS) from Porphyromonas gingivalis, Prevotella intermedia and Porphyromonas gingivalis wild type, and interleukin-1 (IL-1) on production of fibronectin in cultured human fibroblasts. Fibroblasts were obtained from healthy gingiva, inflamed gingiva and healthy periodontal ligament. After the cells had reached confluence, they were further incubated with or without LPS (final concentration: 10. μg/ml) and/or IL-1 (final concentraion: 0.5-5. μg/ml) for up to 48 hours. Fibronectin levels in culture media were measured using enzyme linked immunosorbent assay. Fibronectin levels were increased by in fibroblasts stimulation with LPS or IL-1. Fibronectin levels stimulated by LPS+IL-1 were much increased compared to those stimulated by LPS or IL-1 alone. From these findings, it is suggested that LPS and/or IL-1 may promote fibronectin synthesis in fibroblasts of periodontal tissue in vivo.

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The purpose of this study was to elucidate the mineralizing process of nodules formed by human alveolar bone-derived cells, and changes in phosphatase activities following culture periods. The cells were obtained from human alveolar bone fragments, after the fragments had been treated with bacterial collagenase as described in a previous paper. The mineralized nodule formation and two phosphatase activities of the cells were determined on culture days 10, 14, 28 and 42 after seeding; the enzymes were alkaline phosphatase (ALPase) and acid phosphatase (ACPaes). Cell growth showed logarithmic patterns from day-3 to 10, and reached to confluence on day-14. After confluence, cell numbers increased gradually until day-42. The nodules began to form on day-14, and a small number of nodules, slightly stained by alizalin red S, appeared on day-28, indicating the initiation of the mineralization process. To determine phosphatase activity per 10⁴ cells, enzyme assay was directly carried out using the cells in each well of a 96-well microplate. ALPase activity increased daily, and the highest activity was shown on culture day-14, coinciding with nodule formation. On day-28 and 42, ALPase activity was drastically decreased. On the other hand, ACPase activity was about one tenth of ALPase activity during the culture periods and about one fifteenth on culture day-14.

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The purpose of this study was to evaluate the effects of Nd: YAG laser radiation on scaled and root-planed surfaces using scanning electron microscopy (SEM). The experimental materials were fifteen human teeth affected by severe periodontal disease, which had been extracted because of a hopeless prognosis. All of the teeth had at least 5 mm of attachment loss on the proximal surface tested. One proximal surface was scaled to remove all visible calculus using an ultrasonic scaler and the other proximal surface was root-planed with a Gracey curette. Specimens were cut from the scaled and root-planed proximal surfaces and divided into two groups: scaling group and root planing group. The Nd: YAG laser (power range 0-60 W, CW, 1064 nm) was used at a measured power output of 20 W. The irradiation time was 0.3, 0.5, 1, 2 or 3 s (3 mm beam diameter, distance from the tip to the specimen 5 cm), corresponding to an energy density of 84.93, 141.54, 283.09, 566.17 or 849.26 J/ cm², respectively. In both groups, the center of each specimen was used as the experimental area treated by laser irradiation and the peripheral area of the specimen served as a control. The specimens were then fixed and examined by SEM.
In the scaling group, the control area showed remaining calculus and cementum which had not been removed by the laser irradiation. The surface of the root-planed specimens was irregular, corresponding to the presence of a smear layer, and had an amorphous appearance. Root surfaces of the experimental area in the root planing group exhibited clear orifices of dentinal tubules and intertubular dentin without a smear layer.
The present results indicate that while Nd: YAG radiation is ineffective in removing residual calculus and cementum after scaling, it effectively removes the smear layer, uncovers dentinal tubules, and exposes collagen fibers on the root surface without widening the orifices of dentinal tubules after root planing.

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This study was designed to examine morphological changes of periodontally diseased root surfaces and determine the most effective root surface treatment for connective tissue reattachment and new cementum formation after flap operation.
Each of ten extracted human periodontally diseased teeth was split longitudinally into three pieces. The first group containing of ten root pieces was left untreated, the second was root-planed (RP) and the third was treated with (citric acid CA) following RP. The ultrastructure of the seroot surfaces was examined under transmission electron microscopy. The following results were obtained.
In untreated cementum, collagen fibers were frequently intact or whenever they were degraded, the change was limited to several micrometers in depth from the root surface. In the RP group, the number of specimens with cementum remaining was one -third of the total . In the CA group, the density of the denuded collagen fibers on the dentin surface was lower than that on the cementum surface, and the direction of denuded collagen fibers on cementum varied according to the surface structure. These findings show that collagen fibers of diseased root surfaces change a little morphologically and the almost intact collagen fibers lay bare on the CA treated root surfaces.

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The purpose of this study was to examine the morphological features of cell attachment to the root surface following root-planing (RP) and treatment with citric acid (CA). Each of ten extracted human periodontally diseased teeth was split longitudinally into three pieces for use as samples. The first group of samples was left untreated, the second was RP and the third was treated with CA following RP. Root fragments of the three groups were placed in 35-mm petridishes and seeded with human gingival fibroblasts. After incubation for 4 weeks, the morphological features of the root surfaces were observed by transmission electron microscopy.
The following results were obtained:
1. The fibroblasts accumulating in several layers were spread on the root surfaces of both the RP and CA groups.
2. Extracellular matrix and microfibrils were observed in the space between the root surface and fibroblasts of the CA group, in which the space was wider than that of the RP group.
3. The features of cell attachment on the treated cementum surfaces did not differ from those of treated dentin.

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The effects of Periocline ® administration in combination with scaling (group A) as compared with scaling alone (group B) were examined clinically and bacteriologically.
The results obtained were as follows:
1. Clinical findings, with the exception of plaque index, showed improvement in group A as cornpared with group B throughout the observation periods.
2. Phase contrast microscopically, both total bacterial count and spirochetal and motile rod incidences decreased in group A as compared with group B throughout the observation periods.

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